Dnr: SEE 2021-0089

Report on the activities in 2020 of The Swedish National Infrastructure for

This report presents the activities at Onsala Space Observatory (OSO) during 2020, including the usage of the instruments for scientific purposes, according to the “särskilda villkor” in the contract for operation of OSO between the Swedish Research Council (VR) and Chalmers.

ALMA image of the molecular jet from the nucleus of galaxy NGC 1377 (Aalto et al. 2020); one example of the many ALMA results processed and supported by the Nordic ALMA Regional Centre node at OSO. Left: CO (3–2) integrated intensity image where emission close to systemic is shown in grey scale. The high-velocity (±80 to ±160 km s−1) emission from the molecular jet is shown in contours, with the red and blue showing the velocity reversals. Right: Chart of the various components of the molecular structure of NGC 1377.

Onsala, 15th April 2021

John Conway Director, Onsala Space Observatory

Contents

This report is divided into the following sections. The sections or subsections contain (where relevant) a reference to the corresponding modules defined in OSO’s March 2017 infrastructure proposal to VR. A financial account is provided separately to VR.

1. Operations 2. Key numbers 3. Selected scientific highlights 4. Instrument upgrades and technical &D 5. SKA – The 6. Computers and networks 7. Frequency protection 8. Membership of international committees 9. EU projects 10. Conferences, workshops, schools, etc 11. Education 12. Outreach 13. Changes in organisation 14. Importance to society 15. Importance to industry Acronyms Publications 2020 Key numbers (nyckeltal)

1 Operations

During 2020 Onsala Space Observatory (OSO) operated the following facilities:

– The Onsala 20 m telescope for astronomical Very Long Baseline (VLBI), geodetic VLBI and single-dish astronomy (the latter is not part of VR funded national infrastructure activities but is funded by Chalmers-only sources). – The Onsala 25 m telescope for astronomical VLBI – The Onsala LOFAR station as part of the International LOFAR Telescope (ILT) and in stand-alone mode – The Atacama Pathfinder Experiment telescope (APEX) used for mm wave single-dish astronomy and mm-VLBI – The Nordic ARC node (the Atacama Large Millimeter/sub-millimeter Array Regional Centre node for the Nordic, and Baltic, countries) – The Onsala Twin Telescope (OTT) for geodetic VLBI – The Onsala gravimeter laboratory for absolute and relative gravimetry – The Onsala GNSS stations – The tide gauges at Onsala – Two water vapour radiometers (WVRs) to support space geodesy – The Onsala aeronomy station for observations of H2O, CO, and O3 in the middle atmosphere (funded by Chalmers only) – The Onsala seismometer station – The Onsala time & frequency laboratory

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Operations using the above facilities are described in more detail below under Telescopes (Sect. 1.1), Nordic ARC node (Sect. 1.2), and Geophysical instruments (Sect. 1.3), resp.

1.1 Telescopes [Modules 3, 4 and 5]

In general, all telescopes have operated according to the 2020 activity plan without any major problems, details are given below:

Onsala 20 m telescope: The 20 m telescope was used in accordance with the 2020 activity plan except for a partial one-month stand-down in March-April where only geodetic activities were carried out (any receiver changes were suspended to reduce the risk of SARS CoV-2 transmission). The telescope participated in 44 geodetic 24-hour campaigns, 11 astronomical single-dish projects, 5 extended astronomical VLBI sessions, 10 24-hours astronomical eVLBI sessions, several extended geodetic test runs in synchronisation with the Onsala Twin Telescopes, and 1 teaching/outreach observation. Maintenance (including non-upgrade related technical on-sky observations and equipment repair) were at a mostly normal level except for a persistent cryogenic problem that caused some short interruptions in observations in the autumn of 2020 requiring repeated warmup/cooldown cycles of the 3/4mm receiver. Upgrade-targeted technical activities included: a major undertaking of installing and evaluating new optical sensors for the subreflector tracking system while still fulfilling our commitments by participating in VLBI observations August–December 2020. In addition, the most advanced features in the new Bifrost control system became operational in complex Single-Dish projects leading to some amount of bug-fixing as well as opportunities to find further improvements and higher degrees of automation. Starting in December 2020, the lion’s share of winter science projects were for the first time executed in service mode via observations that were mostly scripted in advance with a single local staff member overseeing multiple projects at once.

Onsala 25 m telescope: The Onsala 25 m telescope was used for astronomical VLBI as planned without any major problems during the year.

Onsala Twin Telescope (OTT): In 2020, The OTT was used for 49 VGOS sessions of different kinds, for a total observing time of approximately 660 hours. See Sect. 1.3 for details.

Figure 1.1. The Onsala Twin Telescope (OTT) and the 25 m telescope. Credit: Magnus Thomasson

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APEX: Swedish APEX observations, during 2020, were conducted on 11 days (less than normal, due to the pandemic), organized in one major observing run in October and a smaller run in late December. To perform service mode observations, OSO normally sends an observing team to Chile for every run. This year no travelling to Chile, from March and onwards, was possible, all observations had to be performed remotely from Sweden with local support at APEX. Several new receivers were installed at APEX in February before the pandemic hit. Two of the receivers cover the 230 GHz and 460 GHz bands and one receiver, the SEPIA 345 GHz receiver, was installed by the GARD/OSO team. None of the receivers could be commissioned fully in March but after intensive remote work with the aid of APEX local support, all the new receivers could be used for scientific work when the observations opened up in September.

LOFAR: The Onsala LOFAR station operates in two main modes: International LOFAR Telescope (ILT) mode and Local mode. In ILT mode, the station is controlled centrally by ASTRON in the . In Local mode the station is controlled by OSO; this observing time is partially allocated via an Onsala open Call-for-Proposals basis and partially via ILT Call-for-Proposals that run in Local mode. In both cases the Local mode time is devoted to pulsar research.

VLBI: Very Long Baseline Interferometry observations were conducted using the Onsala 25 m and 20 m telescopes, and OTT (Onsala Twin Telescope) as part of international networks of telescopes for astronomy and geodesy. The astronomical VLBI observations were scheduled based on recommendations from time allocation committees [for the 20m and 25 telescopes theses TACs are the European VLBI Network TAC and the Global Millimetre VLBI Array (GMVA) TAC]. Geodetic VLBI observations using Onsala telescopes (20 m and OTT) were scheduled by the International VLBI Service (IVS).

The usage of the above telescopes was distributed in the following way:

– The Onsala 20 m telescope: 39 days of astronomical VLBI 44 days of geodetic VLBI 81 days of single-dish astronomy

– The Onsala 25 m telescope: 46 days of regular astronomical VLBI (in addition, observations were carried out on 90 days for the VLBI-campaign PRECISE and magnetar monitoring, see Sect. 4.3)

– The Onsala Twin Telescope: 40 days of geodetic VLBI (for details, see Sect. 1.3)

– The APEX telescope: 11 days of single-dish astronomy on Swedish time

– The LOFAR station: 295 days (ILT), 71 days (local)

Note that time for “normal” technical service, pointing, etc. are not included in the above figures. These service activities amounted to about 16 and 8 days on the 20 m and 25 m telescopes respectively. Test and commissioning observations that are not related to routine maintenance and repairs are not included.

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1.2 Nordic ARC node [Module 2]

The Nordic ALMA Regional Centre (ARC) node provides support to the Nordic community of astronomers to carry out scientific analysis of data taken with ALMA. In this challenging year the node has adapted its activities to continue supporting the user community remotely, from proposal preparation to data reduction and advanced analysis of PI and Archival data. The start of the Covid-19 pandemic coincided with the opening of ALMA Cycle 8 Call for Proposals on March 17th, 2020 (deadline April 15th, 2020). The Nordic ARC had organized visits to the major astronomy institutes in the region, but in order to follow the safety recommendations from our institutions, we adapted our activities to full-online events and offered remote support for proposal preparation by all possible means. The Cycle 8 Call for Proposals was in the first instance extended for at least one month until May 19th, 2020. However, given the situation of the pandemic worldwide, a final decision was taken later on April 17th to suspend the Call for Proposals for one year until 2021. At the same time due to the Covid-19 spread of infections in Chile, ALMA array operations were suspended on March 19th, 2020 to protect the safety of the ALMA staff, which put the Science Observations of Cycle 7 on hold until further notice. The array went to a complete shutdown and shifts of reduced caretaker teams in charge of the safety of the ALMA equipment and infrastructure were organized. For most of ALMA staff work continued remotely. The situation allowed to continue efforts in data reduction and development for the rest of 2020. The ALMA telescope remained closed for the rest of the year. As a consequence, new science observations were not delivered to PIs during this period. Data reduction and quality assessment of the majority of PI observations obtained before the suspension of operations was carried out using the ALMA Science Pipeline by the Joint ALMA Observatory (JAO) in Chile or at ESO. Nordic ARC staff contributed to the data reduction effort of one non-standard Nordic project that was not manageable by the Pipeline and required manual expert intervention. In the past year the Node has supported a total of 19 One-to-one visits of researchers from Swedish institutions to support the analysis of their ALMA projects. The provided support covered aspects from data reduction to advanced analysis, as well as archive mining. Since March 2020 all these ‘visits’ have been virtual and provided online. Each support case has consisted of a first week, on average, of intense support followed by intermittent supervision for a longer period of time. After that, a handful of users continue their processing of ALMA data on the node computing resources. Staff of the Node also participated in providing advice to the Nordic led ESO ALMA Development study “High-Cadence Imaging of the Sun”. The Nordic ARC staff were the initiators and coordinators of I-TRAIN with the European ARC Network, a new regular series of Interactive Training in Reduction and Analysis of INterferometric data. These training sessions cover a wide range of topics of interest to the ALMA user community with the aim of helping users to gain expertise in working with interferometric data. The first events in December 2020 were extremely successful, with 160 participants in the first event and 80 participants in the second. The materials and presentations of the training sessions are available online under the ALMA Science Portal (https://almascience.org/tools/eu-arc-network/i-train), and the videos were put in a YoutTube channel of the European ARC Network. This series of trainings will serve as platform to showcase the use of some of our advanced software tools (https://www.oso.nordic- alma.se/software-tools.php) in future I-TRAIN sessions in 2021. Related to our software tools, UVMULTIFIT has remained as our most widely used tool, with frequent request for support from users worldwide. Our software developers have put

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effort into providing stable installation-packages for the different operating systems as well as to start its migration to CASA 6 in Python 3. As for new developments, the node is actively involved in a project to provide High- level Data Products in the ALMA Science Archive, in particular leading a project aiming at generating new polarization products that will be potentially ingested in the Archive and become available to the public. Nordic node staff contributed to the organization of a Special Session during the last EAS 2020 conference: Special Session 13 "Eight years of ALMA ground-breaking results: A joint venture between the ALMA user community and the ALMA Regional Centres", which served as a unique event to engage with our ALMA user community during the pandemic. During 2020, special efforts from the European ARC Network were directed to reach out to the ALMA user community and to set up online communication channels to maintain users well informed and allow remote interactions. Besides Nordic ARC and EAS 2020 virtual events mentioned above, a European virtual community assembly was organized and all the news were broadcasted by the Nordic ARC through their mailing list that counts with about 80 subscribers. All interactions and meetings among European ARC Network staff also took place online, including our annual EU ARC All-hands in October 2020. Upon request of the ALMA integrated Science Operations Team, the Node lead an investigation on the ALMA End-to-end user experience, and provided recommendations on many aspects that can be improved in the user experience. Nordic ARC staff (3.1 FTE in total) have remained stable during this period at a level below optimum. Unfortunately, recruitment in general has not been possible due to the Chalmers hiring freeze initiated from January 2020 to deal with the university economy imbalance, which has prevented the hiring of new personnel in the OSO Observational Support group and ARC node.

1.3 Geophysical instruments [Module 6]

Geodetic VLBI: The geodetic VLBI observing sessions 2020, using the 20 m telescope with its S/X receiver system, were 24 h long and included regular IVS sessions in the R1-, RD-, RV-, T2-series. In total 44 sessions in the IVS program were observed during 2020. All sessions were recorded with the DBBC2 in vdif-format on the FlexBuff recorder for geodetic VLBI. These data were then e-transferred to the respective correlator. The Onsala twin telescopes (OTT) were used for 24 international broadband VGOS (VO) operational sessions of 24 h duration each, 15 European broadband VGOS (EV) sessions of 4–6 h duration each, and 10 VGOS-B (VB) sessions of 1 h duration. During all these sessions both OE and OW were used in parallel and all data were recorded with the corresponding DBBC3 backends in vdif-format on dedicated FlexBuff recorders. While the international VT- sessions were observed in networks of up to 7 VGOS partner stations, the EV-sessions were observed primarily with two European partner stations, i.e. Yebes and Wettzell. The VB- sessions were observed together on one baseline with station Ishioka in Japan. The VO-sessions are correlated at the MIT/Haystack correlator, the EV-sessions at the correlator, and the VB-sessions at the Onsala correlator. The goal of the VB-sessions is to determine UT1-UTC parallel to simultaneously observed IVS-Intensive sessions with legacy S/X systems. Three out of the 44 S/X-sessions and international 24 VGOS-sessions were common, so-called mixed-mode sessions, where Onsala contributed with all three antennas, On, Oe, Ow.

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Additionally during 2020 sixteen local interferometry sessions were observed using the On-Oe-Ow cluster, with the goal to connect the twin telescopes to the 20 m telescope. These so-called ONTIE-sessions were all planned, scheduled, observed, correlated, fringe-fitted, and analysed at Onsala.

For the other geoscience facilities, the activities are summarised as follows:

GNSS stations: OSO’s primary GNSS station, called ONSA, has operated continuously during 2020. This is a station in the SWEPOS network operated by Lantmäteriet, the Swedish mapping, cadastral and land registration authority. ONSA is also one of the fundamental reference sites used in the global IGS network, as well as in the European EUREF network. An additional station, ONS1, has also delivered data continuously the same networks network. In addition to ONSA and ONS1, the six GNSS stations close to the Onsala twin telescopes were all running continuously during the year.

Gravimeter laboratory: The main purpose of the gravimeter laboratory at Onsala is to maintain a gravity reference and calibration facility co-located with space geodetic techniques. The facility is one component of the Fundamental Geodetic Station. The laboratory is furnished with platforms for visiting absolute gravimeters (AGs), which happens on average one to three times per year. The laboratories primary instrument is a superconducting gravimeter (SCG, model GWR 054). In international context the instrument is called OSG054 and has been operated continuously with very few breaks in recording (less than 10 days) since its installation in June 2009. In 2020 OSG054 has recorded data over 366 days at 1 Hz sampling rate (no missing data). There was one AG campaign from 22–24 June 2020, performed by Andreas Engfeld (Lantmäteriet). A few outliers were found in the residual of the tide analysis on 24 August 2020 when the coldhead was changed. From October 07–10 and 28–31, the dewar was refilled with liquid helium from 81 % to 94 %.

Tide gauges: The Onsala tide gauge station ran uninterrupted for the entire year, excluding the yearly cleaning of the well, causing a data gap of less than 2 hours on the 17th of August. The sea level observations are available from the official web site of national sea level data operated by Swedish Meteorological and Hydrological Institute (SMHI). Onsala’s other GNSS-based tide gauge was also operated continually over the year proving observations with a sampling rate of 1 Hz. Data are stored in Receiver Independent Exchange Format (RINEX) format and include multi-GNSS (i.e. GPS, GLONASS, Galileo, Beidou) code- and carrier-phase obser- vations as well as signal-to-noise ratio (SNR) measurements.

Figure 1.2. The GNSS-based tide gauge in Onsala. Credit: Magnus Thomasson

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Water Vapour Radiometers: The two water vapour radiometers, Astrid and Konrad, are designed to measure the sky brightness temperatures at 21 GHz and 31 GHz from which the radio wave propagation delay in the atmosphere can be inferred. However, during 2020 both instruments were unfortunately not working properly. Astrid needs a major upgrade since its data acquisition system is obsolete. Konrad was operating more or less continuously, but the data quality was impacted by gain jumps. The cause of these jumps has been investigated in the electronics lab at several occasions, but is so far not fully understood.

Aeronomy station: The aeronomy station consists of two radiometers: 1) The single sideband H2O system (water vapour) that measures the sky brightness temperature at 22 GHz, and 2) the double sideband CO/O3 system (carbon monoxide and ozone) that measures the sky brightness temperatures at 111 and 115 GHz. Spectra from both radiometer systems are used to retrieve vertical profiles of the observed molecules in the middle atmosphere. During 2020 both radiometers operated without problems, which means that we have about 340 days of collected H2O and CO/O3 measurements.

Seismometer station: OSO hosts a seismograph station in the Svenska nationella seismiska nätverket (SNSN) led by Uppsala University. We have data access to the local seismometer and keep a continuous archive of its recordings. The station's waveform files are used in delay calibration of the superconducting gravimeter and for noise reduction in absolute gravity measurements. The seismological centre in Uppsala noticed irregular signals unlikely to be due to earthquakes. The site was checked, a crack on the pillar was repaired and a young tree next to it cut, no more irregular records were observed since then.

Time and frequency laboratory: The time and frequency laboratory hosts the hydrogen maser, necessary for VLBI observations, but which also contributes to the universal atomic time. OSO also collaborates with RISE (Research Institutes of Sweden) on a Swedish time-keeping system. RISE owns a second hydrogen maser and a cesium clock that are installed at Onsala. These instruments are used for comparison measurements and provide redundancy of accurate reference time (and frequency) for the VLBI observations (both astronomy and geodesy) at the observatory.

2 Key numbers

2.1 Astronomy [Modules 2, 3, 4, 5]

Detailed key numbers for the astronomy activities are given in tables at the end of this report and in a separate excel file. Here we give only a few comments, a summary of the publication statistics, and some key numbers for single-dish observations with the 20 m telescope.

Users of the astronomy research infrastructure The ALMA user project/user statistics given at the end of this report and in the associated excel file are for Proposal Cycle 7; that is for observations covering the period October 2019 – September 2020. In conjunction with the annual ALMA deadline the Nordic ARC node is very active in advertising the use of ALMA in Sweden and the Nordic countries and a significant

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number of Nordic/Swedish ALMA project proposals are generated by these Nordic ARC publicity efforts. We note that for ALMA, APEX, astronomical VLBI, and LOFAR taken together, about 28 % of the Swedish users (individuals) were from other institutions than Chalmers. The Swedish non-Chalmers users were affiliated with Stockholm University and Uppsala University. About 25 % of the users in 2020 were women. There was this year a small difference in success rate (fraction of applications for telescope time which are observed) between men and women. All users did research in the subject area 103 Physical Sciences.

Number of refereed scientific papers The associated excel file gives a list for each instrument of papers in refereed journals published in 2020 (see also the publication list at the end of this report). Conference publications are not included (except for a few geoscience publications). Below are given summary statistics of papers for each instrument/activity. For each instrument two figures are given; in most cases the first number is the total number of instrument-related publications while the second is the number of publications with at least one Swedish author. In contrast for ALMA the first number is the number of papers with at least one Nordic author. The Nordic ARC provides standard support for all projects with Nordic PIs, and further dedicated support upon request. The level and type of Nordic ARC node support for each publication is described in the accompanying excel file. Alongside the raw numbers for ALMA publications below, on the same line, we give the total number of papers with at least one Nordic/Swedish author that have received dedicated Nordic ARC node support. The bulk of publications that received dedicated Nordic ARC support are lead by first authors with Nordic/Swedish affiliation (and vice-versa nearly all Swedish-led proposals get dedicated ARC node support). In contrast no Nordic ARC support is generally given to ALMA publications which have Nordic/Swedish affiliated co-authors but which are lead by first authors from other countries. For APEX, publications based on all partners’ observing time are counted because OSO contributes to the full APEX operations costs and because Swedish receivers are used by all partners. The numbers for astronomical VLBI include observations with EVN, GMVA, EHT and users of JIVE. Publications by OSO staff on technical R&D are also presented. A publication list is found at the end of this report.

• ALMA 82/46, Nordic ARC node dedicated support 17/13 (Nordic/Swedish) • APEX 67/5 total/Swedish) • Astronomical VLBI 30/13 (total/Swedish) • LOFAR 77/9 (total/Swedish) • 20 m telescope, single-dish 6/2 (total/Swedish) • Technical publ. by OSO staff 8

In addition, in 2020 there was one publication using astronomical data from the satellite Odin (now operating mainly in aeronomy mode), and 5 publications using data from the Swedish- ESO Submillimetre Telescope SEST (closed in 2003).

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Onsala 20 m telescope, single-dish observations Single-dish observations with the 20 m telescope in Onsala are not supported by VR (but by Chalmers funding) and key numbers for them are therefore not given in the tables at the end of this report. We note that in 2020, there were proposals for 11 projects, out of which 10 were observed, plus one from a previous proposal cycle. There were 11 female and 20 male users on the observed projects. Of these, 11 were Swedish (all from Chalmers).

Figure 2.1. The radome with the 20 m telescope in Onsala. Credit: Magnus Thomasson

2.2 Geosciences [Module 6]

Users of the geoscience research infrastructure The OSO geoscience instruments, including the geodetic VLBI observations as the major activity, do not have individual scientific users who apply for observing time. Rather the geoscience instruments make long-term measurements of Earth parameters – which are thereafter stored in international databases with open access. Since these databases are open access, it is impossible for us to acquire detailed insight in the user groups in terms of which universities or other organisations they belong to and the gender distribution of the users. The data and derived products such as station positions, Earth’s orientation/rotation rate and gravity field are then used both by the global geophysics community for scientific purposes and by civil society for a variety of practical applications including supporting accurate geo-location services and monitoring of global change. As far as we know, all use of the data for scientific purposes was within the subject area 105 Earth and Related Environmental Sciences.

Number of refereed scientific papers We have identified 8 papers with one or more Swedish authors and 15 papers with non-Swedish authors published during 2020 where the use of data or services from OSO are specifically stated. In addition, there are significantly more papers making use of OSO data products, especially those using GNSS reference data from OSO via IGS/EUREF, that cannot be identified because the inclusion of the OSO station is not explicitly mentioned. It is also likely that there are papers published that we simply are not aware of. A publication list is found at the end of this report. We are not aware of any patents originating directly from our geoscience activities. No user has been rejected to use OSO geoscience data. This is in any case not a readily computable statistic since as described above virtually all of the OSO geoscience data are automatically distributed via open data bases.

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Data submissions Geodesy VLBI: The geodetic VLBI observations are carried out within the framework of the International VLBI Service for Geodesy and Astrometry (IVS), http://ivscc.gsfc.nasa.gov. In total 44 experiments, each one with a length of 24 h and rather evenly spread over the year, were carried out during 2020 with the Onsala 20 m telescope. Additionally, we have been observing with the Onsala twin telescopes during several VGOS sessions, both international (24 sessions, 24 h each) and European (15 sessions, 4–6 h each) ones, plus 10 one-baseline intensive sessions (1 h long). During three so-called mixed-mode sessions, both the 20 m telescope and the OTT were observing. Correlated VLBI observations are provided via the IVS data archives and are available free of charge. The IVS registers its data also under the umbrella of the World Data System (WDS), which is an Interdisciplinary Body of the International Council for Science (ICSU). Databases as well as products are supplied to users around the globe with minimum latency in order to guarantee that operation critical information, in particular Earth orientation parameters from VLBI observations, are available for satellite operators, space agencies, and other stakeholders. These databases are fundamental for many scientific disciplines with Geophysics. Given also that global navigation satellite systems like GPS, would not be operable without the Earth orientation parameters provided from VLBI measurements, the true value chain and the number of users of products emerging from data collected at globally distributed VLBI sites, like Onsala, has significant economic value to society; given that everybody relying on GNSS positioning and navigation has in the end use of the data.

GNSS: The two major GNSS reference stations at OSO, i.e. ONSA and ONS1, are nodal points for the Swedish permanent GNSS network, SWEPOS, hosted by Lantmäteriet. All data acquired continuously are openly distributed via the data archives of IGS https://webigs.ign.fr/gdc/en/, and EUREF http://www.epncb.oma.be/. These archives serve thousands of users every year. Additionally, GNSS data are recorded with six stations distributed around the Onsala twin telescopes, called OTT1 to OTT6 with data stored at Lantmäteriet. It should be noted that the need for using GNSS data from OSO is motivated by the fact that the stations are co-located with one of the most accurately determined VLBI stations world-wide. Therefore, indirectly also the VLBI data are used via the GNSS data from OSO. Many cases are found in the research community where GNSS data are used with OSO acting as a reference site in global, regional and local studies. A vast majority of the downloads, that occur from the international databases operated by IGS and EUREF, are by universities and research agencies for studies of, e.g., plate tectonics, crustal deformation, space weather, sea level, climate, meteorological monitoring, et cetera. Thus, OSO provides both the national and international user communities with a robust and accurate link to the international reference frame. Also during 2020 the GNSS station OSOI has been operated and contributed to ESA’s ionospheric monitor network.

Gravimeter Laboratory: Gravimeter data with one-second samples and maximum with a two-minutes latency is publicly available, see http://holt.oso.chalmers.se/hgs/SCG/monitor-plot.html. The records are also submitted to the archive of IGETS (International Geodynamics and Earth Tide Service) at GeoForschungsZentrum (GFZ) Potsdam (), on a monthly routine. OSO delivers 1- minute down-sampled data, raw and “corrected”, i.e. cleaned from earthquake signatures. IGETS is a service under the auspices of the International Association of Geodesy (IAG). During 2020 one visit with an absolute gravimeter, Lantmäteriet's FG5, took place.

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Ocean tide loading service: Since 2002, OSO provides a computing service for ocean tide loading effects in application to surface displacements and gravity (http://holt.oso.chalmers.se/loading). Being endorsed by the IERS, its main purpose is to provide consistent reduction of these effects to VLBI, GNSS and SLR analysis centres in their preparation of products that maintain the ITRF. Apart from this, the service’s logbook hints at a large number of users peripheral or outside the ITRF community in their analysis of GNSS observations. Loading-induced displacements are computed from a range of global ocean tide maps, using 28 sources featuring 8 to 11 tide species each.

Tide gauges: The data from the super tide gauge are transferred to SMHI in near-real time. These are available to the public through the SMHI web pages.

Aeronomy station: During 2020 OSO collected about 340 days of H2O data derived from its aeronomy station. These data are being processed to be delivered to the Network for the Detection of Atmospheric Composition Change (NDACC; see http://www.ndsc.ncep.noaa.gov ). During 2020 OSO has collected 340 days of CO/O3 data.

3 Selected scientific highlights

Below follows a list of scientific highlights selected to illustrate the different instruments and science areas covered by OSO. In the listed publications Swedish authors are shown underlined.

Astronomy

Especially highlighted in this section are papers from Swedish astronomers using OSO telescopes or receiving user support provided at OSO (via for instance by the Nordic ARC Node). In addition, some interesting international results that make use of OSO telescopes and/or instrumentation are listed.

3.1 ALMA [Module 2]

ALMA resolves the remarkable molecular jet and rotating wind in the extremely radio-quiet galaxy NGC 1377

Aalto, S.; Falstad, N.; Muller, S.; Wada, K.; Gallagher, J. S.; König, S.; Sakamoto, K.; Vlemmings, W.; Ceccobello, C.; Dasyra, K.; Combes, F.; García-Burillo, S.; Oya, Y.; Martín, S.; van der Werf, P.; Evans, A. S.; Kotilainen, J. Astronomy & , Volume 640, page 204 (2020)

Summary: Studying outflows, winds, jets and other mechanical feedback processes in galaxies is important to our understanding of how galaxies evolve both in the local and distant Universe. Feedback from active galactic nuclei (AGN) and starbursts may for example help limit the growth of massive galaxies and of supermassive black holes (SMBHs).

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Figure 3.1. Left: CO (3–2) integrated intensity image where emission close to systemic is shown in grey scale. The high-velocity (±80 to ±160 km s−1) emission from the molecular jet is shown in contours, with the red and blue showing the velocity reversals. Right: Chart of the various components of the molecular structure of NGC 1377: the molecular jet and narrow wind, the slow wind and the suggested bow shocks.

With very high-resolution (20 by 30 mas (2×3 pc)) ALMA observations of CO (3–2), HCO+

(4–3), vibrationally excited HCN (4–3) ν2=1f, and continuum, Aalto et al. studied the remarkable, extremely radio-quiet, molecular jet and wind of the lenticular galaxy NGC 1377 (Fig. 3.1). The outflow structure is resolved, revealing a 150 pc long, clumpy, high-velocity (< 600 km s−2), collimated molecular jet where the molecular emission is emerging from the spine of the jet with an average diameter of 3-7 pc. A narrow-angle (50°−70°), misaligned and rotating molecular wind surrounds the jet, and both are enveloped by a larger-scale CO-emitting structure at near-systemic velocity. The jet and narrow wind have steep radial gas excitation gradients and appear turbulent with high gas dispersion (σ > 40 km s−1). The jet shows velocity reversals that Aalto el al. propose are caused by precession, or more episodic directional changes. Aalto el al. further suggest that an important process for the molecular jet and narrow wind is likely magneto-centrifugal driving. An asymmetric, nuclear r < 2 pc dust structure with 24 −2 a high inferred molecular column density N(H2) >10 cm is detected in continuum and vibrationally excited HCN. The nuclear dust emission is hot (Td >180 K) and its luminosity is likely powered by a buried AGN. Aalto el al. suggest that the SMBH of NGC 1377 is at the end of an intense phase of accretion and evolving from a state of more extreme nuclear obscuration. The nuclear growth may be fuelled by low-angular momentum gas inflowing from the gas ejected in the molecular jet and wind. Such a feedback-loop of cyclic outflows and central accretion would be an effective process in growing the nuclear SMBH and thus would constitute an important phase in the evolution of NGC 1377. This also invites new questions as to SMBH growth processes in obscured, dusty galaxies.

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DEATHSTAR, first results: CO envelope sizes and asymmetries

Ramstedt, S.; Vlemmings, W. H. T.; Doan, L.; Danilovich, T.; Lindqvist, M.; Saberi, M.; Olofsson, H.; De Beck, E.; Groenewegen, M. A. T.; Höfner, S.; Kastner, J. H.; Kerschbaum, F.; Khouri, T.; Maercker, M.; Montez, R.; Quintana-Lacaci, G.; Sahai, R.; Tafoya, D.; Zijlstra, A. Astronomy & Astrophysics, Volume 640, page 133 (2020)

When solar-like reach the end of their lives they develop massive winds. Over time, the wind will remove the entire stellar atmosphere and lead to the death of the . Material that is enriched with new elements formed inside the star is thereby recycled in the galaxy and will make up new stars and planets. This process is well established, but the accuracy of current measurements is insufficient to properly constrain stellar wind and evolutionary models. DEATHSTAR is a large project aimed at improving the accuracy of stellar wind- parameter measurements. Significant uncertainty is related to assumptions made regarding the size and shape of the circumstellar envelope created by the wind. By mapping the envelopes, this uncertainty is reduced or even removed. The DEATHSTAR sample consists of 180 nearby (< 1 kpc) stars on the asymptotic giant branch (AGB). In this paper by Ramstedt et al., the circumstellar envelopes of 42 southern stars have been mapped in two CO transitions, J=2–1 and 3–2 with ALMA ACA.

Figure 3.2. Comparison between measured CO(2–1) envelope sizes (triangles) and expected sizes (lines) from photodissociation models plotted against a measure of the circumstellar density. Carbon stars are red. M-type stars are blue. Filled symbols are Mira variables. The dashed and dotted lines show the predicted full photodissociation diameter from models [Mamon et al. ApJ 328, 797 (1988); Saberi et al. A&A 625, A81 (2019)]. The solid lines show the expected Gaussian full-width half- maximum (FWHM) of the CO(2–1) emission determined from radiative transfer modeling of the recent photodissociation from Saberi et al. (2019).

First results include that about one third of the envelopes show strong signs of anisotropy and cannot have been created by a smooth wind. Furthermore, the envelope sizes are significantly different from what has previously been assumed, probably mainly due to discrepancies in the CO abundance. For carbon stars (C/O > 1), the envelopes can be up to a factor of 2 larger and for M-type stars (C/O < 1), the maps show the opposite trend (see Fig. 3.2). To a first

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approximation, this will translate into the opposite change in mass-loss rate, i.e., current mass- loss rate estimates for carbon and M-type stars could be too large and too small by up to a factor of 2, respectively. The CO- abundance of circumstellar envelopes of different spectral types are estimated from chemical models, but this is the first time it can be constrained observationally.

3.2 APEX [Module 3]

Submillimetre water masers at 437, 439, 471, and 474 GHz towards evolved stars. APEX observations and radiative transfer modelling

P. Bergman and E. M. L. Humphreys Astronomy & Astrophysics 638, A19 (2020)

Summary: This study describes submillimetre spectral line observations in the 400 GHz regime using the Swedish Heterodyne Facility Instrument (SHFI) at the APEX telescope. The study aimed to detect high-frequency water masers towards several evolved stars. One of the detections is shown in Fig. 3.3. The observations were interpreted by means of radiative transfer modelling of the emission from water molecules. It was found (see Fig. 3.3) that the observed 9 water masers can become very strong in gas clouds/clumps with high density (~10 H2 molecules per cm3) and high temperature (~1000 K) especially if mixed with somewhat cooler (Tdust ~ Tgas/2) dust particles.

Figure 3.3. Left: APEX SHFI observations in the 400 GHz regime toward the evolved star U Her (a Mira type variable star) on two different epochs. Top spectra are from CO while the water maser lines are indicated by their frequencies (437, 439, 471, and 474 GHz). Some SiO lines are shown (but not detected in this source). Right: Radiative transfer model results to determine the physical conditions (H2 density, gas kinetic temperature, and dust properties) when water masers become strong. The contour diagrams depict the maser (line frequency in GHz indicated) intensity relative the ground state non- masing water line at 557 GHz using a logarithmic scale. The four panels describe different dust properties (dust temperature and gas-to-dust mass ratio). It is found that a high gas H2 density (~109 cm−3) and high kinetic temperature (~1000 K) is needed to produce strong maser emission. Also, having less warm dust (Tdust < Tgas) seems to boost the maser action further. Another important find is that these models do not predict strong 437 GHz masers which is contrary to what is observed (see left figure) and it is clear that the models have to refined using a better physical description of the inner region of these stars. In addition, effects of line overlap may have to be taken into account.

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The surprisingly carbon-rich environment of the S-type star W Aql

E. De Beck and H. Olofsson Astronomy & Astrophysics 642, A20 (2020)

Summary: A detailed APEX study of the S-type star W Aql. An S-type star is a special kind of Asymptotic Giant Branch (AGB) star with as much carbon as oxygen in its atmosphere. W Aql was studied using spectroscopy over the very large frequency band 159-268 GHz. The lower part of this band was covered by the Swedish-ESO SEPIA B5 receiver. In total 84 spectral lines were detected and most of them were identified with about 25 different molecular species (when also counting isotopic variants). Despite the equal amounts of carbon and oxygen in the stellar atmosphere the chemistry in the more extended circum-stellar envelope seems more similar of carbon-rich stars implying that the current chemical models have to be refined for this kind of stars.

3.3 Astronomical VLBI [Module 4]

Accreting intermediate-mass black holes: more jets could be detectable in dwarf galaxies

J. Yang, L.I. Gurvits, Z. Paragi, S. Frey, J. Conway, X. Liu, L. Cui, MNRAS, 495, L71, 2020

Summary: Nuclei in optically faint dwarf galaxies may host relatively light black holes with 6 masses < 10 M☉, i.e. intermediate mass black holes (IMBHs). With VLBI observations, Yang et al. 2020 have discovered a rarely seen powerful IMBH jet in the dwarf galaxy J0906+5610, Fig. 3.4. This finding indicates that more IMBH jets could be detectable in particular in nearby dwarf galaxies with the existing radio facilities. IMBHs are very rare objects in the local Universe because of the rapid growth of galaxies and black holes. Finding these nearby faint “leftover” objects would shed light on the formation and growth of seed black holes and jet activity in the very early Universe. To date, jetted radio-emitting outflows compact on sub-pc scales have been revealed in only one dwarf galaxy, NGC 4395. The dwarf elliptical galaxy J0906+5610 host an IMBH with 5 a mass of about 4x10 M☉ at ~93 Mpc. The recent VLBI observations of J0906+5610 reveal two 1 mJy extended jet components. Compared to the first IMBH jet in NGC 4395, the second IMBH jet in J0906+5610 has ~160 times larger structure and ~100 000 times higher radio luminosity. In Fig. 3.4, the yellow cross and circle mark the central position and the error circle of the optical counterpart. The northern feature in the top region is located in the yellow circle and most likely represents the inner jet base or emerging jet component launched by the accreting IMBH. The southern elongated feature might be a dying jet component ejected in the early time. Owing to no significant stellar activity in the host galaxy, the observed radio structure can only result from the central IMBH jet activity.

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Figure 3.4. A two-component brightness distribution found by the EVN at 1.66 GHz in the dwarf galaxy SDSS J0906+5610 hosting an accreting IMBH. The yellow cross and circle mark the optical (Gaia DR2) centroid and the error circle.

A repeating fast radio burst source localized to a nearby spiral galaxy

B. Marcote, K. Nimmo, J. W. T. Hessels, S.P. Tendulkar, C.G. Bassa, Z. Paragi, A. Keimpema, M. Bhardwaj, R. Karuppusamy, V.M. Kaspi, C.J. Law, D. Michilli, K. Aggarwal, B. Andersen, A.M. Archibald, K. Bandura, G.C. Bower, P.J. Boyle, C. Brar, S. Burke-Spolaor, B.J. Butler, T. Cassanelli, P. Chawla, P. Demorest, M. Dobbs, E. Fonseca, U. Giri, D.C. Good, K. Gourdji, A. Josephy, A.Y. Kirichenko, F. Kirsten, T.L. Landecker, D. Lang, T. J.W. Lazio, D.Z. Li, H.- H. Lin, J. D. Linford, K. Masui, J. Mena-Parra, A. Naidu, C. Ng, C. Patel, U.-L. Pen, Z. Pleunis, M. Rafiei-Ravandi, M. Rahman, A. Renard, P. Scholz, S.R. Siegel, K.M. Smith, I.H. Stairs, K. Vanderlinde, A.V. Zwaniga. Nature, 577, 190, 2020

Summary: Fast radio bursts (FRBs) are brief, bright, radio flashes. Their physical origin still remains unknown and today dozens of possible models have been proposed. Using the EVN, Marcote et al. (2020) reported the precise localisation of a second repeating FRB source, FRB 180916.J0158+65, Fig. 3.5. This source was originally discovered in 2018 by the CHIME telescope in Canada. With this location the team were able to conduct observations with the 8 m Gemini North on Mauna Kea in Hawaii. Examining the environment around the source revealed that the bursts originated from a spiral galaxy at redshift of ~0.0337, specifically, from the apex of a prominent v-shaped star-forming region. The location is radically different from the previously located repeating FRB, but also different from all previously studied FRBs. Marcote et al. (2020) suggest that repeating FRBs may have a wide range of luminosities and originate from diverse host galaxies and local environments.

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Figure 3.5. Each individual burst is imaged by using the EVN gated visibility data (a, b, c and d). e: Image using the full span of the EVN observation and 2-s integration time; no significant (>3σ) persistent radio emission is detected at the positions of the bursts (denoted by the red cross) and no signal above the 4σ level is detected anywhere within the full field. f: The positions derived from each individual burst and their associated 1σ uncertainties (orange), with respect to the weighted-average burst position (black).

The case against gravitational millilensing

S. Asadi, E. Zackrisson, E. Varenius, E. Freeland, J. Conway, K. Wiik, MNRAS, 492, 742, 2020

Summary: VLBA observations of the quasar B1152+199 at 5 GHz in 2001 revealed two images of a strongly lensed jet with seemingly discordant morphologies; see top row of Fig. 3.6. Whereas the jet appears straight in image A, image B exhibits slight curvature on milliarcsecond scales. This is unexpected from the lensing solution and has been interpreted as possible evidence for secondary, small-scale lensing (millilensing) by a compact object, with a mass of 5 10 M☉, located close to the curved image (Rusin et al. 2002; Metcalf 2002). The probability for such a superposition is extremely low unless the millilens population has very high surface number density. Asadi et al. (2020) revisit the case for millilensing in B1152+199 by combining new global VLBI data at 8.4 GHz with two data sets from the EVN at 5 GHz (archival), and the previously published 5 GHz VLBA data. They find that 5 GHz EVN data, with a more circular synthesized beam, exhibits no apparent milliarcsecond-scale curvature in image B (Fig. 3.6; middle row). Various observations of the object spanning ~15 yr apart enable them to improve the constraints on lens system. Asadi et al. (2020) argue that the only plausible explanation for the apparent curvature in the original VLBA images is artificial, due to the particular combination of the shape of the synthesized beam and the relative angle and structure of the radio jet.

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Figure 3.6. The two macrolensed images of B1152+199 from the re-imaged 2001 VLBA 5 GHz dataset (top row), the 2012 EVN 5 GHz data-set (middle row), and the 2015 Global VLBI array 8.4 GHz data set (bottom row). In each case, the beam size is indicated in the lower left corner.

3.4 LOFAR [Module 5]

Direct Radio Discovery of a Cold Brown Dwarf

Vedantham, H.K., Callingham, J.R., Shimwell, T.W., Dupuy, T., Best, W.M.J., Liu, M.C., Zhang, Z., De, K., Lamy, L., Zarka, P., Röttgering, H.J.A., and Shulevski, A. Astrophysical Journal Letters 903, page L33 (2020)

Summary: This paper presents the first tentative detection of cyclotron radio emissions from a brown dwarf. Radio cyclotron emissions come from magnetized plasma around objects such as our Sun, brown dwarves or exoplanets with magnetic fields. Such a direct detection opens the door to e.g., the direct detection of magnetized exoplanets. Having a magnetic field would give exoplanets an important feature in common with the Earth, a feature that has been speculated to facilitate the establishment of life.

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LOFAR4SpaceWeather (LOFAR4SW) – Increasing European Space-Weather Capability with Europe’s Largest : Beyond the Detailed Design Review (DDR)

Bisi, M. M., Ruiter, M., Fallows, R. A., Vermeulen, R., Robertson, S. C., Vilmer, N., Rothkaehl, H., Matyjasiak, B., Verbiest, J., Gallagher, P. T., Olberg, M., Carozzi, T., Lindqvist, M., Carley, E., Krüger, P., Mevius, M., Baldovin, C., and Barnes, D. EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14948, https://doi.org/10.5194/egusphere-egu2020-14948 (2020)

Summary: The LOFAR4SW project was presented to the general geophysical society at the European Geophysical Union’s online conference. It announced the fundamental features and capabilities with regards to space weather that an enhanced LOFAR could provide. Science cases include monitoring of heliospheric radio bursts, ionospheric scintillation, and coronal mass ejections in the solar wind.

3.5 Onsala 20 m telescope single dish

2020 was a productive year in terms of scientific single dish observations. Among other things, a two-year collaborative Bonn-Onsala observational campaign was concluded in March 2020 and led to a featured A&A article in early 2021 (Jacob et al., A&A 647, A42, to be presented in more detail in the forthcoming Activity Report). Several comets were also observed and this multi-year effort had now accumulated enough data to allow the production of a paper that is in a near-submission state (Bergman et al., A&A, in prep.). Below, we show two articles that were published during the calendar year of 2020 using Onsala 20 m telescope data.

A Survey of High Mass Star Forming Regions in the Lines of Deuterated Molecules

Trofimova, E.A., Zinchenko, I.I., Zemlyanukha, P.M., Thomasson, M. Astronomy Reports, 64, 244-258 (2020)

Summary: By observing 60 Giant Molecular Clouds in deuterated species in the 4 mm band + + (DCN, DNC, DCO , N2D ), deuteration degrees were estimated and some important conclusions could be drawn, such as a temperature variation in the DCO+ relative abundance whereas the HCN deuteration degree – and DCN/DNC abundance ratio – is approximately constant in the 15−55 K range.

NGC 7538 IRS1 – an O Star Driving an Ionized Jet and Giant N-S Outflow

Sandell, G., Wright, M., Güsten, R., Wiesemeyer, H., Reyes, N., Mookerjea, B., and Corder, S. Astrophysical Journal, 904, 139 (2020)

Summary: Details about the embedded young O star NGC 7538 IRS1 and its associated ionized and molecular outflows could be revealed using a multitude of observations with different telescopes (Fig. 3.7). These results lead the authors to suggest that IRS1 is a single O star and that O stars can form in a similar manner to low-mass stars. They further suggest that the high accretion rate is quenching the formation/expansion of a classical HII region and the ionising flux can only escape into the jets.

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Figure 3.7: Onsala 20 m telescope mapping of the 13CO 1-0 transition was used to fill in the large scale emission structure in these CARMA interferometry contour maps of the low (L), intermediate (I), and high (H) velocity components of the molecular outflow.

3.6 Geosciences [Module 6]

Below are listed a selection of papers utilizing data produced by the Onsala geophysical instruments as part of international networks.

On the organization of CONT17

Behrend, D., Thomas, C., Gipson, J., Himwich, E., Le Bail, K. Journal of Geodesy 94, 100, (2020)

Summary: The Continuous Very Long Baseline Interferometry (VLBI) Campaign 2017 (CONT17) was observed from November 28 to December 12, 2017 and featured three independent observing networks. Two legacy S/X networks of nominally 14 stations each observed in parallel for the full 15 days of the campaign. One of them was made possible in large part by the participation of the ten-station network of the long baseline observatory. Furthermore, for the 5-day period from December 4 to 8, 2017, a six- station broadband network continuously recorded VLBI global observing system data. The different networks will help probe the accuracy of the VLBI estimates of the Earth orientation parameters and investigate possible network biases. We describe the organizational efforts undertaken to realize CONT17, including the analysis of resources such as recording media, electronic data transfer, and correlation, the assignment of stations to the three networks, and source selection and schedule writing.

The third realization of the International Celestial Reference Frame by very long baseline interferometry

Charlot, P., Jacobs, C., Gordon, D., Lambert, S., de Witt, A., Böhm, J., Fey, A., Heinkelmann, R., Skurikhina, E., Titov, O., Arias, F., Bolotin, S., Bourda, G., Ma, C., Malkin, Z., Nothnagel, A., Mayer, D., MacMillan, D., Nilsson, T., Gaume, R. Astronomy & Astrophysics 644, A159 (2020)

Summary: A new realization of the International Celestial Reference Frame (ICRF) is presented based on the work achieved by a working group of the International Astronomical Union (IAU) mandated for this purpose. This new realization, referred to as ICRF3, is based on nearly

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40 years of data acquired by very long baseline interferometry. The ICRF3 includes positions at 8.4 GHz for 4536 sources, supplemented with positions at 24 GHz for 824 sources and at 32 GHz for 678 sources, for a total of 4588 sources. A subset of 303 sources among these, uniformly distributed on the sky, are identified as "defining sources" and as such serve to define the axes of the frame. Source positions are reported for epoch 2015.0 and must be propagated for observations at other epochs for the most accurate needs, accounting for the acceleration toward the Galactic center, which results in a dipolar proper motion field of amplitude 0.0058 milliarcsecond/yr (mas/yr). The frame shows a median positional uncertainty of about 0.1 mas in right ascension and 0.2 mas in declination, with a noise floor of 0.03 mas in the individual source coordinates. A subset of 500 sources is found to have extremely accurate positions at 8.4 GHz, in the range of 0.03 to 0.06 mas. Comparing ICRF3 with the Gaia Celestial Reference Frame 2 in the optical domain, there is no evidence for deformations larger than 0.03 mas between the two frames. Significant positional offsets between the three ICRF3 frequencies are detected for about 5 % of the sources. Moreover, a notable fraction (22 %) of the sources shows optical and radio positions that are significantly offset. There are indications that these positional offsets may be the manifestation of extended source structures. This third realization of the ICRF was adopted by the IAU at its 30th General Assembly in August 2018 and replaced the previous realization, ICRF2, on January 1, 2019.

SNR-based GNSS reflectometry for coastal sea-level altimetry: results from the first IAG inter-comparison campaign

Geremia-Nievinski, F., Hobiger, T., Haas, R., Liu W., Strandberg, J., Tabibi, S., Vey, S., Wickert, J., Williams, S. D. P. Journal of Geodesy 94, 70 (2020)

Summary: Ground-based Global Navigation Satellite System Reflectometry (GNSS-R) is quickly maturing toward the objective of becoming a viable alternative for operational coastal sea-level (SL) altimetry in a geocentric reference frame. SL has immense societal implications related to climate change. Of particular interest is the exploitation of existing coastal GNSS sites for reflectometry by means of signal-to-noise ratio (SNR) observables. We report results from the first inter-comparison campaign on SNR-based GNSS-R. The goal was to cross- validate retrieval solutions from independent research groups under comparable conditions. This action was an initiative of the International Association of Geodesy working group 4.3.9 (2015–2019 term). Data collected at the Onsala Space Observatory for a 1-year period (2015– 2016) were compared to a co-located tide gauge (TG). SNR data for the GPS L1-C/A signal were processed by four groups, in Sweden, Luxembourg/ Brazil, Germany, and the UK. Semidiurnal tidal constituents showed good agreement between TG and all GNSS-R groups. SL variations at diurnal and longer periods were also well captured by all series. Most GNSS- R solutions exhibited spurious tones at integer fractions of one sidereal day, the satellite revisit time of the particular GNSS employed (GPS). Band-pass filtering between 3 h and 30 h confirmed that the dominant tidal components were well captured by most GNSS-R solutions. Higher-frequency SL variations (periods < 3 h) are poorly represented by GNSS-R as a consequence of its low temporal resolution. The solution with the worst agreement neglects a correction associated with the rate of change in sea level and uses narrower satellite elevation ranges per retrieval. Overall, there was excellent agreement, with correlation coefficients exceeding 0.9 and RMSE smaller than 5 cm.

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3.7 Device and Terahertz technology [Module 8]

Waveguide-to-substrate transition based on unilateral substrateless finline structure: Design, fabrication, and characterization

López, C., Desmaris, V., Meledin, D., Pavolotsky, A., Belitsky, V. IEEE Transactions on Terahertz Science and Technology 10, 668 (2020)

Summary: We report on a novel waveguide-to-substrate transition with prospective use for broadband mixer design. The transition employs a substrateless finline, i.e., a unilateral finline structure with the substrate removed between the fins. This distinctive feature diminishes the overall insertion loss and facilitates matching with the waveguide. The transition is designed on a thin silicon substrate covered by a superconducting niobium thin layer. An auxiliary Au layer situated on top of the Nb layer provides grounding for the fins and facilitates the mounting process in the split-block waveguide mount. Aiming to compare simulations with measurements, a back-to-back transition arrangement for the 211−373 GHz frequency band was designed, fabricated, and characterized at cryogenic temperatures. The simulation results for the back-to-back structure show an insertion loss of less than 0.6 dB in the whole band, i.e., 0.3 dB per transition. Furthermore, a remarkable fractional bandwidth of 55 % with a return loss better than 15 dB is predicted. Experimental verification shows consistent results with simulations. For the sake of comparison between simulations with measurements, a test structure comprising two transitions in a back-to-back arrangement was designed. In order to facilitate mounting and improve the mechanical strength of the assembly, silicon tips were introduced in the structure, as depicted in Fig. 3.8. These tips extend from the primary substrate and fit inside cavities located in the lower half of the split block. The simulation results for the performance of the back-to-back structure at 4 K are depicted in Fig. 3.9. For cryogenic temperature, an insertion loss less than 0.6 dB and a return loss better than 15 dB is achieved over the whole band.

Figure 3.8. Back-to-back arrangement. The upper and lower halves of the block are depicted separately. The structure incorporates lateral silicon tips to facilitate mounting.

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Figure 3.9. Simulated scattering parameters for the back-to-back arrangement. The S11 magnitude is better than 15 dB, and the insertion loss is below 0.6 dB in the 211–375 GHz frequency band.

4 Instrument upgrades and technical R&D

4.1 ALMA [Modules 2 & 8]

Several aspects of the ALMA Observatory development roadmap towards 2030 (https://www.almaobservatory.org/en/publications/the-alma-development-roadmap/) continued their progress in 2020. Work progressed for the new correlator technical specifications. Unfortunately, testing and deployment of new receivers suffered delays due to Covid-19. Despite the situation, Band 2 pre-production contracts were signed in May and limited testing started. The production of Band 1 receivers on the other hand was well advanced although their installation was halted by the Observatory lab closure. Among many parallel developments, one can highlight the progress done by the ALMA Development project ARI-L (https://almascience.eso.org/alma-data/aril), which reached a milestone in producing and ingesting its first 60,000 data cubes and continuum images in the ALMA Science Archive by re-imaging Cycle 2–4 observations with the ALMA Imaging Pipeline. With respect to R&D on ALMA receivers, during 2020 GARD completed a three-year ESO funded project as part of ALMA Update Program. The first par of this project related to the development of a new type of superconducting tunnel junctions, SIS, with AlN tunnel barrier. This part was completed with high-quality junctions being fabricated using GARD dedicated equipment in the Chalmers Clean Room Facility, MC2. The specific capacitance of these junctions was studied and characterized leading to a possibility using the new SIS junctions in a demonstration mixer. Such demonstrator SIS mixer employing Nb-AlN-Nb SIS junction and operated in the frequency range of 270-375 GHz was successfully designed and built by GARD. This mixer was tested and experimentally confirmed low noise performance close to 4 times of the quantum noise, hf/k, where f is frequency and h and k are Planck and Boltzmann constants respectively. In addition, completing the second part of the ESO project, GARD demonstrated that the new SIS junctions could provide broadband IF performance, 3.5–

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15.5 GHz, an improvement of a factor of 3 improvement in bandwidth over the current ALMA receivers. Following the successful completion of the above described above project, GARD received funding by ESO for two new research projects as part of ALMA Update Program. The new projects largely are a continuation of the earlier project and aim to further develop technology for AlN SIS junctions with reduced area and ultra-wideband SIS mixer operation between 200 and 400 GHz. During this period, Onsala Space Observatory has continued its involvement in the RadioNet JRA RINGS, in particular working on full polarisation and beam modelling for polarisation calibration with ALMA (and LOFAR). The Nordic ARC has also continued providing advice for the ALMA Development Study “High-Cadence Imaging of the Sun” (PI: S. Wedemeyer).

4.2 APEX [Modules 3 and 8]

Like for society in general, the operation of the APEX telescope was affected by the pandemic in 2020. For instance, from mid-March to the end of the year no international travels could be made to Chile. Also, the travel within Chile was quite restricted and between late March and early September only a very limited-sized crew was allowed at APEX just to keep the instrumentation safe. During this time, no sky access was possible but some technical tests of the instruments could be performed. Early in the year and before the pandemic outbreak, instrument teams from Max Planck Institute (MPI) for Radio Astronomy and GARD/OSO installed three different receivers. MPI started the installation of the two nFLASH receivers working in the 230 GHz and 460 GHz bands, respectively. The GARD/OSO team installed the SEPIA 345 GHz receiver which occupies the third slot in the SEPIA cryostat (the other two slots being used by the SEPIA 180 GHz and 660 GHz receivers). Most of the installations, including the receiver control software, could be completed in February but only limited sky-tests could be performed before the APEX lock-down in March. Throughout the entire lock-down period, technical receiver tests and evaluations were performed remotely with the aid of the remaining APEX lock-down crew and several receiver problems could be remedied together with minor upgrades of the receiver control software. In order to improve the SEPIA345 receiver tuning, GARD provided an external RF signal source, which was installed at the receiver and it provides extended functionality allowing to verify sideband rejection and fine-tune the SEPIA345 for best performance. Additionally, a script run on the SEPIA control software for room temperature and cold receiver integrity check was tested in the lab and now could be used a APEX. In mid-September, the APEX operations were ramped-up and, by the end of the month, technical and scientific observations could start. The observations were at first limited to 10 hrs during Chilean night-time with the help from remote observers in Europe. Later, in November, this was expanded to 15 hrs per day to also include morning observations. The sky tests with the SEPIA345 receiver could continue and the first science observations were done in October. Its exact status as an APEX instrument will be determined in May 2021 but it was demonstrated that the sensitivity of the SEPIA345 receiver was better than or near the specification requirements in the lower half of the frequency band. Going to higher frequencies, it showed a decline in sensitivity but still being useable for most science observations. It should be noted that in November 2020, the last Laboca bolometer array observations were made and this bolometer array will be decommissioned and hence not available in 2021.

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4.3 Astronomical VLBI [Module 4]

OSO is involved in the VLBI related H2020 project JUMPING JIVE. During the reporting period, OSO has continued its involvement in work package 7, (WP7, The VLBI future) and work package 8 (WP8, Global VLBI interfaces). The main deliverable of WP 7 was completed in 2020 in the form of a White Paper addressing several relevant points in setting the future priorities of VLBI science capabilities. WP8 addresses two main issues, the first is scheduling of observations and the second is the continuous monitoring of the status of stations participating in VLBI sessions. The BRoad-bAND (BRAND) RadioNet project developed a revolutionary decade frequency range (1.5-15.5 GHz) receiver for VLBI. OSO led the feed design for the first prototype which was optimised for the prime-focus geometry of the Effelsberg 100 m telescope. The feed was sent in 2019 to Effelsberg in Germany for integration in the receiver cryostat. Due to the Covid-19 pandemic completion of this receiver has been delayed. During 2020, OSO has been investigating a solution for wideband feeds on secondary configured reflectors, with high f /D geometry, which is very common among the EVN telescopes. A concept developed for the Onsala 20 m utilizes dual-offset mirrors plus feed for the frequency range of 4–15.5 GHz (CXKu-band); sooverlapping the BRAND-frequencies down to 4 GHz. This feed is based on the BRAND 1.5–15.5 GHz feed and Onsala has been investigating how in general to modify such a feed to make suitable for use on high f /D reflectors. OSO was involved in the RadioNet JRA Radio Interferometry Next Generation Software (RINGS). The main objective for RINGS was to deliver advanced calibration algorithms for the next generation of radio astronomy facilities, characterized by a high sensitivity, a high bandwidth and long baselines. During 2020, OSO completed WP7.5. It dealt with an advanced calibration algorithm for radio interferometry data. In particular, an algorithm for robust self- calibration that applies to full-polarization visibility data and implements direction dependent effects corrections has been implemented. The algorithm has been implemented in a python module called RobVisCal, which utilises casacore functionality, and has been made publicly available on Github. Since May 2019 the Onsala 25 m telescope has taken part in a VLBI-campaign (PRECISE) that regularly observes Fast Radio Bursts that have been reported to repeat as discovered by the CHIME telescope in Canada. The ad-hoc array is composed of most of the smaller (<40 m) telescopes that also take part in EVN-observations viz Onsala, Torun, Irbene, Medicina, Noto, Badary, Svetloe, Zelenchukskaya, Urumqi, Shanghai, and Westerbork. Since January 2020, the telescopes in Effelsberg and Sardinia also take part in a subset of the observations. The 25 m telescope has been used for 34 days in 2020. In addition to that, OSO has been monitoring magnetars and HMXBs as potential galactic sources of FRBs. This is work is done in collaboration with Westerbork and Torun. In total, the 25 m telescope was used for 56 days in 2020. For data recording and data processing purposes, a dedicated server ('flexbuff') was purchased. This machine contains ~120 TB of disk space for data recording, another ~30 TB of disk space, 20 CPUs and one GPU for data processing. OSO has developed an end- to-end processing pipeline that converts raw baseband data stored as VDIF to filterbank format (i.e. channelised Stokes I time series). Subsequently, the pipeline searches the filterbank files for bright, short duration bursts (e.g. fast radio bursts, single pulses from pulsars), classifies the found candidates via a neural network either as RFI or real. In the latter case plots of the candidates are sent to a dedicated Slack-channel. In this way, required human interaction is kept to a minimum. Besides searching the data taken with the 25 m dish at Onsala, we also search the data taken with Effelsberg, the , Westerbork-RT1, and Torun. The data from those stations are streamed to the very same server at OSO, are searched, and

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baseband data are deleted in case of no detections. The generated filterbanks are down sampled and stored for archival purposes. Both Wb-RT1 and Torun will invest in purchasing/upgrading infrastructure to run the pipeline we developed locally. In this way, turn-around times will be shorter, and the workload be spread more evenly between the participating stations.

4.4 LOFAR [Module 5]

Last year saw the completion of the EU funded project RINGS in which OSO was tasked with researching advanced radio astronomy techniques, with special focus on LOFAR. In particular, OSO developed a robust method for calibrating fully polarimetric visibility data from LOFAR. A report was written and delivered to the EU. The technique allows the calibration of station interferometric data even in the presence of noise by using singular value decomposition to isolate statistically significant flux components in visibility data. Also during last year, OSO led the design of software for LOFAR4SW, which also is an EU financed project. We completed the Detailed Design Review (DDR) which was done completely virtually. The DDR documents and the work that went into them were heavily based on the software development carried out at OSO on the iLiSA. An import part of the work on LOFAR4SW has been outreach activities, since LOFAR4SW is about space physics not radio astronomy. OSO is a national infrastructure geared mainly towards radio astronomy and therefore has well established connections with the astronomical community in Sweden, but it does not as many connections with the space physics community, which is quite considerable in Sweden. Therefore, we have initiated liaisons with, e.g., the Swedish Institute for Space Physics (Institutet för Rymdfysik, IRF) by giving presentations of LOFAR4SW. This outreach across national science communities has re- enforced the case LOFAR4SW, namely that relatively cheap upgrades of LOFAR could open additional infrastructure exploitation possibilities also for space sciences. Finally, OSO continues to exploit the Swedish LOFAR station for local use. We support a long running pulsar survey lead by a PI in Paris, and a VLBI like pulsar study by a PI in Bonn. We are also exploring the technical possibilities for doing fast radio burst (FRB) observations, and hope to see more of these in the future, since low frequency of LOFAR is a unique window on these sources.

4.5 The Onsala 20 m telescope [Modules 4,6]

During summer 2020 a new set of linear sensors were deployed for the 20 m antenna sub- reflector positioning system. These new sensors have higher accuracy then the former and was chosen to improve the system. The two sensors in X- and Y-axis uses mechanical sensors, while the three in Z-axis uses laser sensors. The use of laser-based sensors was mainly due to mechanical reasons, the sensor type used in X- and Y-axis would not fit, but another reason for using laser sensors was to remove any mechanically caused errors. After extensive telescope testing in the fall of 2020, the system behaviour is now being evaluated long-term during normal observations. The main problem with the previous sensor suite – short scale non-linearities that led to Z-position dependent pointing errors that the pointing model cannot compensate for – seems to have been eliminated. However, there are two other issues that are not fully understood yet; an increased random pointing error in the vertical direction, and an elevation dependent longterm pointing drift. The former is likely related to transient oscillations in the subreflector vertical tilt that is more noticeable during short integrations such as pointings. The latter could be a “settling effect” with the new hardware, or in the worst case, it could be a thermal/seasonal

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variation introduced by the new hardware (that would be revealed by a drift in the opposite direction over the next 6 months). On the software side, the most important improvement in 2020 likely is the ability of the Bifrost control system to automatically switch between different science projects. This feature was crucial in our response to the Covid-19 pandemic where – with rare exceptions – we ran all projects in service mode with only one Astronomer-On-Duty managing the observations.

4.6 Geoscience [Module 6]

Two new systems have been installed on the OTT. A shutter system to block RF from entering the receiver when the system is not in use, and a focal finder used to find the best placement along the Z-axis of the receiver in the receiver cabin. The shutter system uses a metal-based jalousie placed directly in front of the window of the receiver cryostat. The system can presently only be operated at 0° elevation, but future improvements will be made to be able to open and close it at any other angles. The system has been incorporated on the Ow telescope, and will be incorporated on the Oe telescope during 2021. The focal finder consists of a small stepper motor operated system that can move the receiver around the supposed best Z-axis placement of the receiver. The idea is to use this system to find the best placement, and then using shims to permanently set the receiver in the correct position along the Z-axis. The system is presently used in the Oe telescope but will be moved to the Ow telescope during 2021.

4.7 Development of new millimetre/sub-millimetre devices [Module 8]

R&D activities at GARD were largely affected by the Covid-19 pandemic. GARD work include effort with equipment, e.g., in the laboratories and Chalmers Clean Room facility. Because of Covid-19, the staff presence and work were limited following the recommendations by Swedish authorities and Chalmers administration. GARD continued its R&D work anyways but we had to change the way we work to appropriate the constrains and circumstances. During 2020, GARD worked on several internal and external projects. Staff successfully completed and commissioned the new computer control system for the GARD sputter tool in the MC2 Clean Room. A significant effort was made to improve technology of installing chips and mounting circuits in the cryogenic blocks operating at 4 K physical temperature. Serious efforts were made to improve and modify the wire-bonding technology used for cryogenic mixers and amplifiers. GARD designed and built a laboratory cryostat for 4 K operation aiming at replacing the use of cryostats with extremely expensive liquid helium. GARD has mainly completed its commitment within H2020 RadioNet AETHRA program, the new receiver, SEPIA345, with IF broadband SIS mixers, 4–12 GHz and RF 270–375 GHz, was developed, built, installed at APEX and recently completed commissioning. Some insignificant part of AETHRA was descoped because of the Covid-19 pandemic. GARD successfully completed the project on ALMA Upgrade Program, by developing a new type of SIS junctions with AlN tunnel buried and demonstrated these SIS junctions in the mixer with ultra-wideband IF performance. In the Spring 2020, ESO approved the ALMA Band 2 Development and pre- production project. GARD owns the role of the cold cartridge designer in this prestigious international project with partner institutions from the Netherlands (NOVA, Groningen), and Italy (INAF, Palermo). During 2020, the preparation technical and component work and building ALMA Band 2 Consortium activities took place. As example of the development of

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Terahertz components, we present here the publication by C. López, V. Desmaris, D. Meledin, A. Pavolotsky, V. Belitsky, “Design and Implementation of a Compact 90-degree Waveguide Twist With Machining Tolerant Layout” (IEEE Microwave and Wireless Components Letters, vol. 30, p. 741, 2020). Figure 4.1 demonstrates the idea behind this novel device and its performance.

Figure 4.1. Left: Proposed waveguide twist. (a) Cross section view and waveguide ports. (b) Photo- graph of the fabricated twist. (c) Waveguide twist layout. Right: Measured and simulated scattering parameters for the fabricated twist.

5 SKA – The Square Kilometre Array [Module 9]

5.1 Introduction

The Square Kilometre Array is the next major step forward in centimetre and metre wave radio astronomy, consisting of two new interferometric arrays with greatly enhanced sensitivity and sky survey speed compared to existing radio telescopes. SKA will be built in two phases with phase 1 (SKA1) construction scheduled to start in Q3 2021 with its completion expected by 2028. The part of SKA1 operating at cm wavelengths (SKA1-mid) will be constructed in South Africa by adding 133 dishes to the existing 64 dish MeerKAT array (inaugurated in July 2018). The metre wavelength part (SKA1-low) will be built in Australia utilizing the infrastructure of the MWA SKA precursor telescope. The global headquarters of the SKA project are located at Jodrell Band in the UK. Chalmers University of Technology, representing Sweden, has since 2012 been a member of the SKA Organisation (SKAO), a non-profit UK company tasked with designing the SKA telescope. OSO Director John Conway is the Swedish scientific member of the SKAO board together with Swedish voting member Lars Börjesson (Advisor to Chalmers Rektor on national and international infrastructures). An international convention to establish a new SKA Observatory inter-governmental organisation (IGO) before the end of 2020 was signed and ratified by six countries (though not yet Sweden) which is a sufficient quorum to allow the new international organsiation to be called into existence. It is planned that the new SKA Observatory will begin operating in January 2021 with its first council meeting planned for

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early February. During 2021 the new IGO will gradually take over the functions of the SKA Organisation with the goal that the latter organisation can be disbanded during the year. In Sweden following on from a proposal submitted to VR which was very positively evaluated, it was agreed by VR in principle in late 2019 that Sweden should join the SKA Observatory and would contribute to construction and operations subject to assembling within Sweden all the necessary funding. During 2020 such funding discussions were concluded between VR and VINNOVA on jointly providing the Swedish part of construction funding (the vast majority of which will return to Sweden as contracts for industry). At the end of August 2020 VR formally applied to the government for Sweden to join the new SKA Observatory international organisation; at the time of writing this application is being processed by the government with a final decision likely before mid-2021. In parallel with these actions Chalmers and VR during 2020 finalised a new contract covering the period 2021–2025 which will finance both the radio astronomy activities at OSO and the future Swedish annual contributions to SKA. This contract will come into force and replace the present VR – OSO contract (covering 2018–2021) as soon as possible in 2021 when Swedish membership of the new SKA Observatory is confirmed.

5.2 Swedish industrial contributions to SKA1 constructions

During the year there were extensive discussions between SKA partner countries and SKAO on the allocation of the industrial work packages for SKA construction. These discussions were coordinated on behalf of Sweden by the Swedish Industrial Liaison Officer (ILO), Patrick Carlsson of Chalmers Industrial Technology (CIT). The conclusion of these discussions was that Sweden was defined as the ‘Level 1’ lead for two work packages, namely for the SKA1- mid Band 1 receiver and for SKA1-mid Digitizers. Discussions were also held between Sweden countries interested in committing Level 2 deliverables within those two work packages. In addition, a Swedish company (Low Noise Factory) was identified as a Level 2 supplier of Low Noise Amplifiers to at least one other SKA1-mid receiver band in addition to Band 1. For the digitizer work that Sweden leads at Level 1 a procurement was executed in mid- 2020 for a company to work on industrialization of the Band 1,2,3 Digitizer design. This procurement was run by Chalmers Industrial Technology (CIT) on behalf of OSO and was won by Quamcom AB, a local Gothenburg company. Quamcom started work on the Digitizer development in September 2020.

5.3 SKA Observatory Development Programme

The proposed SKA Observatory construction plan provides, once constructions has begun in earnest (2022 onward), for an Observatory Development Programme (ODP) developing future SKA technology. Via the ODP SKA Observatory central funding will be available to fund studies and prototyping. The ODP will initially be at a moderate level but will grow in scope toward the end of the SKA1 construction phase (mid-to-late 2020’s). OSO has for many years been leading SKA efforts in wideband receiver technology. OSO during 2020 coordinated with leaders of the Phase Array Feed SKA interest group in setting up an open collaboration on SKA receivers and front-end digital electronics which will coordinate efforts in this technology area (including holding annual technical meetings) – especially by acting as a bridge to when ODP funding becomes fully available.

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5.4 SKA Regional Centre planning and SKA Data Challenges

A vital component of the SKA project will be a network of SKA Regional Centres (SRCs) which will collectively form the archive of the data that SKA users will access. At computer centres close to the SKA1-mid and SKA1-low telescopes in South Africa and Australia raw SKA data will first be converted into Observatory Data Products (such as data cubes of radio intensity versus spatial coordinates and frequency) – which will then be transferred to the distributed SRC sites. At SRC sites these ODPs will be converted into Advanced Data Products (ADPs) such as catalogues of sources (requiring AI and Machine Learning processing). Sweden is expected to provide its share of SRC resources in terms of data storage and computation, most likely as part of a coordinated European effort. During 2020 Sweden fully participated in the SRC Steering Committee (SRCSC) whose mission is to plan in detail the worldwide SRC network. During the year the SRCSC set up a set of six working groups to plan in detail the implementation of the SRC; with each working group containing representatives from each SKA country. The appointed Swedish SRCSC-WG representatives are drawn from a mixture staff from OSO (4 people), members of the new Chalmers e-Commons organisation (3 people) and from SNIC (1 person). A vital aspect of future SRC future functionality will be applying Machine Learning (ML) and Artificial Intelligence (AI) techniques to the analysis of SKA data. In order to gain experience with ML techniques in the SKA context OSO during 2020 executed a joint project with the Chalmers Fraunhofer Centre for Industrial Mathematics in which one of the published algorithms developed for the SKA Data Challenge 1 (SDC1) competition in 2019, involving automatic source recognition in simulated SKA continuum data, was implemented and improved. This work was carried out partly in preparation for a joint OSO plus Fraunhofer team to formally enter the competition for SKA Data Challenge 2 (SDC2) during the first half of 2021; with SDC2 consisting of a challenge to accomplish automatic source recognition in simulated 3D atomic hydrogen spectral line cubes.

6 Computers and networks [Module 10]

During 2020, the OSO cluster at the SNIC–C3SE, (SNIC: Swedish National Infrastructure for Computing; C3SE: Chalmers Centre for Computational Science and Engineering) node at Chalmers had its 100 TB Lustre file allocation migrated to a dedicated NFS storage server with a new capacity of 410 TB enabling the processing of ever larger data sets from ALMA and LOFAR, (earlier dimensioned to allow an international LOFAR data set, 40 TB, plus two large ALMA data sets, 20 TB, to be processed). At OSO, a new 20-core computer was installed, including a Tesla T4 GPU, dedicated to searching for Fast Radio Bursts (FRB). For processing highly RAM dependent data sets, a new NAFCI, (NAtional Computer InfraStructure) machine was installed at Onsala equipped with 48 cores capable of speeds up to 4 GHz, 1.5 TB RAM and 50 TB storage, with space available for further storage. Three computers located at OSO were moved to a data centre at Chalmers dedicated for use by the Astronomy group. As well, a new backup system was implemented for the NAFCI machines at Onsala, providing a full backup of home-directories as well as Python scripts used for processing ALMA data located on the large storage partitions on the machines. Network connections to OSO presently support the transmission needs of geodetic VLBI (1 Gbit/s), astronomical VLBI (1–4 Gbit/s) and LOFAR (3 Gbit/s). OSO is a fully-fledged node of SUNET. Presently OSO rents multiple 10 Gbit/s fibre connections to SUNET, used for ordinary network traffic, plus a dedicated lightpath to the Netherlands for transfer of LOFAR

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and astronomical VLBI data. There is also an option to transmit data in IP format, used for sending data to other stations/correlators. Major work has been done with various control systems for OSO telescopes and equipment.

7 Frequency protection [Module 10]

On behalf of European radio astronomers, the Committee on Radio Astronomy Frequencies (CRAF, https://www.craf.eu) of the European Science Foundation coordinates activities to keep the frequency bands used by radio astronomy and space sciences free from interference. CRAF has Member Institutes (radio observatories, national academies or funding agencies) in 20 countries, sometimes more than one per country. CRAF has a chairman and a secretary, and it employs a full-time Frequency Manager. Sweden is represented in CRAF via OSO. From June 2019 the chairman is from OSO. In addition, OSO is also contributing to the expenses of the CRAF Frequency Manager, currently stationed at JIVE, The Netherlands. CRAF represents European Radio astronomy at international meetings where possible threats to radio astronomy occur. During 2020, work in CRAF has been fully reorgainsed into several small teams, so- called Work Item (WI) teams, which deal with well-defined topics such as satellite services (including the so-called mega-) or questions of spectrum engineering. Some of the WI teams are active on both International Telecommunication Union Radiocommunication Sector (ITU-R) and European Conference of Postal and Telecommunications Administrations Correspondance Group (CEPT) related issues. Preparations for the World Radio Conference 2023 (WRC23) study cycle has started at both the ITU-R and CEPT levels in 2020. The agenda items of most importance at this preliminary stage of the cycle are the use of the high-altitude platform stations as International Mobile Telecommunications Service (IMT) base stations (HIBS), non-safety aeronautical mobile applications and space research services (SRS) applications. Other agenda items regarding the global maritime services (GMDSS) and space weather sensors are also of interest and are currently being tracked. The decision to upgrade the radio astronomy service (RAS) secondary band 608–614 MHz to a primary allocation is under consideration depending on the demand for this band in Europe. CRAF is participating in meetings, submitting documents, at all levels (including national) in order to get the support from the adminstrations. CRAF contributed to a report, Fig. 7.1, presented at the workshop Dark and Quiet Skies for Science and Society. The report contained two recommendations: (1): Non-Geostationary Satellite Systems (GSO) satellites should be required to be able to avoid direct illumination of radio telescopes and radio-quiet zones, especially the radar and other high-power satellite applications that are capable of burning out a radio astronomy receiver. (2): Non-GSO satellites should be required to have sidelobe levels that are low enough that their indirect illuminations of radio telescopes and radio-quiet zones do not interfere, individually or on aggregate. Those recommendations, along with others discussed during the meeting for protecting, will be debated at a series of United Nation subcommittees in 2021 before going to United Nations Office for Affairs (UNOOSA) and, ultimately, the U.N. General Assembly for approval. CRAF was one of organiser of the 5th The Scientific Committee on Frequency Allocations for Radio Astronomy and Space Science (IUCAF) School on Spectrum Management for Radio Astronomy. It was held in Stellenbosch in South Africa from March 2nd to March 6th, 2020. The event website is at http://www.iucaf.org/sms2020/. The school

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attracted a record number of 53 participants from Europe, Asia, the USA, Australia and South Africa.

Figure 7.1. Cover of Dark & Quiet Skies report.

The OSO CRAF member, apart from being the chairman and being involved points above, focuses also on interference issues at local and national levels (e.g., via contacts with the Swedish Post- och telestyrelsen, PTS). One example of an issue during 2020 has been seeting terms of coordination with OSO for indoor usage of 5G around Onsala/Kungsbacka in the 24.25–25.1 GHz band.

8 Memberships of International Committees

During 2020 OSO was represented on the following international boards and coordinating committees. The OSO Infrastructure Director John Conway serves on many of these boards.

– The European VLBI Network (EVN) for astronomical VLBI (the Director was until July chairman of the board, and Michael Lindqvist is member of the Programme Committee) – The Joint Institute for VLBI ERIC (JIVE), a European Research Infrastructure Consortium that operates the EVN correlator in Dwingeloo (NL) and supports the EVN activities (the Director is a council member and since June 2019 Chairman of the Council). – The APEX project board – representing the three partners that operate the 12 m diameter sub-mm telescope APEX in northern Chile (the Director is a board member)

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– The International LOFAR Telescope (ILT) Board, which oversees the operation of the ILT (the Director is a board member) – Jumping JIVE, an EU-financed Horizon 2020 project to develop European VLBI (the Director is a board member) – RadioNet, an EU-financed Horizon 2020 project, which coordinates all of Europe's leading radio astronomy facilities (The Director is a board member, Michael Lindqvist is leading the Networking Activity Dissemination) – The SKA Organisation (SKAO), the British company that is responsible for the SKA project in its pre-construction phase (the Director and Lars Börjesson, Chalmers, are board members) – SKA Regional Centre Steering Committee (The Director is a member). – SKA communications steering committee (Robert Cumming is a member) – International Astronomical Union Office for Astronomy Outreach (Robert Cumming is the IAU National Outreach Coordinator for Sweden) – LOFAR for Space Weather (LOFAR4SW), an EC funded (H2020 INFRADEV) design project (the Director represents Chalmers in the project) – International VLBI Service for Geodesy and Astrometry (IVS), which operates geodetic VLBI (Rüdiger Haas is a Directing board member) – International Earth Rotation and Reference Frame Service (IERS) (Rüdiger Haas is a board member) – The European VLBI Group for Geodesy and Astrometry (EVGA) (Rüdiger Haas is Chairman) – Inter-Commission Committee on Marine Geodesy (ICCM) (Rüdiger Haas is an IERS Representative to the Steering Committee) – Inter-Commission Committee on Geodesy for Climate Research (ICCC) (Gunnar Elgered is a member of JWG C.2 Quality control methods for climate applications of geodetic tropo- spheric parameters) – Galileo Scientific Advisory Committee (GSAC) of the European Space Agency (Gunnar Elgered is a member) – ESF Committee on Radio Astronomy Frequencies (CRAF) for the protection of the radio band for radio astronomical use (Michael Lindqvist is chairman)

9 EU projects [Modules 2, 4, 5, 8, 9]

During the year OSO participated in three EU Horizon 2020 projects (proposals submitted in 2016 and 2017): RadioNet, JUMPING JIVE and LOFAR4SW.

9.1 RadioNet

RadioNet joins together 28 partners, amongst them institutions operating world-class radio telescopes, as well as organisations performing cutting-edge research, education, and development in a wide range of technology fields that are important for radio astronomy. OSO is part of the Transnational Access (TA) program via APEX and the EVN, and participates in the Networking Activities. OSO also plays an important role in all three of its Joint Research Activities (JRA) which includes both software and hardware development. RadioNet includes the following JRAs:

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• Advanced European Technologies for Heterodyne Receivers for Astronomy (AETHRA) aims at exploiting new technologies, such as highly integrated microelectronic semi- or superconducting circuits, to significantly improve the next generation receivers of mm and sub-mm wavelength telescopes, reinforcing European technological and scientific leadership by considerably improving the receiver performance and observing speed of the European-owned world leading facilities ALMA, APEX, NOEMA and PV. (See also Sect. 4.7.)

• BRoad bAND EVN (BRAND EVN) is developing and building a prototype broad-band digital receiver, which will cover a frequency range from 1.5 GHz to 15.5 GHz. The BRAND receiver when deployed at a majority of EVN telescopes has the potential to catapult EVN to new levels of performance not achievable with any other astronomical VLBI network. The BRAND receiver might even become the next generation VGOS receiver for geodesy VLBI due to its superior sensitivity, its wider bandwidth, and the possibility to choose parts of the spectrum still uncontaminated by RFI. (See also Sect. 4.3.)

• Radio Interferometry Next Generation Software (RINGS) will deliver advanced calibration algorithms for the next generation of radio astronomy facilities, characterized by a high sensitivity, a high bandwidth and long baselines. The functionality delivered by RINGS will be incorporated in the CASA software package. (See also Sect. 4.4.)

RadioNet started January 2017 and ended December 2020.

9.2 JUMPING JIVE

Joining up Users for Maximising the Profile, the Innovation and the Necessary Globalisation of JIVE (JUMPING JIVE) aims to prepare and position European VLBI for the SKA era, and to plan the role of the ERIC JIVE, as well as the EVN, in the future European and global landscape of research infrastructures. On a European scale, the proposed activities are designed to raise the profile of JIVE/EVN among scientists and operators of radio astronomical facilities, by widely advocating its science capabilities and its role as research infrastructure provider within the international radio astronomy community. These activities focus on outreach and on reinforcing science cases for the next decade. (See also Sect. 4.3.) JUMPING JIVE started December 2016 and will run for four years. In 2020, the project was extended to 31 July 2021, in order to minimise the impact of Covid-19 into the project activities.

9.3 LOFAR4SW

The LOFAR for Space Weather (LOFAR4SW) project will deliver the full conceptual and technical design for creating a new leading-edge European research facility for space weather science. It also supports outreach and dialogue with a range of stakeholders in the space weather community, regarding the possible subsequent implementation, potential future use, and governance aspects of a LOFAR4SW data monitoring facility. Designing for LOFAR a significant upgrade in hardware, algorithms, and software will allow to create, at a fraction of the cost of building a new facility, a large-scale cutting-edge research facility providing simultaneous independent access to both the radio astronomy and the space weather research communities. LOFAR4SW will in particular address capabilities to monitor Solar dynamic spectra, scintillation measurements of densities and velocities in the

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inner heliosphere, and high-resolution measurements of Total Electron Content (TEC) variations in the Earth’s ionosphere. A strong point of the LOFAR4SW is to uniquely enable provision of the missing link of global measurements of the interplanetary magnetic field – a key parameter in forecasting the severity of geomagnetic storms. (See also Sect. 4.4.) LOFAR4SW started December 2017 and will run for 3.5 years. In 2020, the project was extended to 28 February 2022, in order to minimise the impact of Covid-19 into the project activities.

10 Conferences, workshops, schools, etc.

European ARC Network Special Session 13 in the European Astronomical Society Annual Meeting 2020

Nordic ARC node staff contributed to the organization of a Special Session during the last EAS 2020 conference. In particular Special Session 13 "Eight years of ALMA ground-breaking results: A joint venture between the ALMA user community and the ALMA Regional Centres". The aim of the Special Session was to bring together the European ALMA users and the researchers providing support at the different European ARC Nodes. It was a great opportunity for users of ALMA to present new scientific results and share observation and data reduction strategies, foster collaborations and brainstorm on future developments. Scientific talks were complemented with contributions from experts from the European ARC Network. Participation in the session was competitive. Three time slots of 1.5 h duration each scheduled a total of 16 presentations (invited & contributed) and 15 posters. A panel discussion was also held on the topic of ALMA user needs. The SOC ensured contribution from origin and diversity and seniority. The session was very well attended (54–60 attendees in all time slots). The EAS 2020 conference was held online for the first time due to the Covid-19 situation. It was a very successful event in number of participants and countries of origin.

Figure 10.1. The Nordic ARC node contributed to the organization of a Special Session 13 “Eight years of ALMA ground-breaking results” during the EAS 2020 conference.

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11 Education

The OSO national infrastructure staff do not generally take part in the academic teaching at Chalmers (except for, e.g., a few guest lectures on specialized radio astronomy observing techniques or current research). The infrastructure does however support teaching by making a small fraction of the time on its telescopes available for exercises by students on Chalmers and other Swedish academic courses. The staff are also sometimes involved in teaching and providing exercises at specialised graduate level schools that are organised from time to time at the Observatory. Specifically, at Chalmers, the 20 m telescope and SALSA were used in astronomy and physics courses, the 25 m telescope in a satellite-communication course, GNSS equipment in a satellite-positioning course, and laboratory equipment in courses on microwave, millimetre wave, and THz technology. Students in the Engineering physics programme at Chalmers made a virtual visit (due to the pandemic) to the Observatory as part of the course Experimental physics.

12 Outreach

With the exception of the project SALSA för högstadiet (see below), outreach activities at OSO are funded entirely by Chalmers and not part of the national infrastructure’s VR funding. During 2020, only 280 people visited Onsala Space Observatory, its telescopes and exhibition, most of them school students visiting as part of ten guided tours held in January and February. After that, visits were restricted according to Chalmers and Folkhälsomyndigheten’s recommendations, and only two visits, for six persons or fewer, were carried out. Public events were cancelled. Instead, we supported Chalmers and Onsala scientists’ participation in digital events, in particular Sweden’s Day and Night of Astronomy in September and the rescheduled Gothenburg Science Festival in October. During the year planning continued for a new visitor centre at the observatory. A project working group involvimg OSO staff worked on coordinating the project in collaboration with Chalmers’s fundraising office, Chalmersfastigheter and our host department at Chalmers (Space, Earth and Environment, SEE). In parallel we have begun to develop digital alternatives to physical guided tours. The project Rymdskolan, developed by astronomers Kiana Kade and Chiara Ceccobello at our host department, organises digital interactive lessons in astronomy aimed at high-school (gymnasium) students in Gothenburg schools in areas with low socioeconomic status. Also, a five-minute film of aerial footage from the observatory was made available on Youtube and launched on the Day and Night of Astronomy. From October 1, a reorganisation of outreach staff was implemented. A team of six PhD students (each at 0.1 FTE) is led by Robert Cumming (1.0 FTE). Our two small SALSA radio telescopes were booked for an average of nearly 45 hours per week, with on average 2 h per booking, by students, teachers and amateur astronomers from 23 countries, among them Sweden, Romania, India, Mexico, Ghana and Australia. Most users study the movements of interstellar gas in the Milky Way, and we provided supervision for a small number of Swedish high school projects of this kind. During 2020 we noted increased interest in using the the telescopes as part of online meetings and events directed at the public, astronomy clubs and student audiences. At Chalmers and at universities in Italy, Germany and the US we know of online sessions being run by teachers to replace and complement physics laboratory exercises. In October we started the VR-funded MINT project SALSA för högstadiet,

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aimed at developing SALSA’s user interface and projects to suit younger schoolchildren (years 7–9). We communicated news from Onsala facilities and research by Chalmers scientists to the media in collaboration with Chalmers press office and partner organisations. We reported for example on new discoveries in the field of fast radio bursts, the citizen science project Zoo: LOFAR and new results from ALMA. The staff handled media enquiries on astronomical topics and were regularly quoted in news media. We also supported department scientists who gave a number of public talks during the year. In particular, several took part in events in the series Astronomy on Tap organised in Gothenburg, which took place both live and online during the year.

13 Changes in organisation [Module 1]

There were no significant changes in organisation within OSO during 2020. There were no changes to the membership of the OSO Steering Committee (see http://www.chalmers.se/en/centres/oso/about-us/Pages/Organization.aspx). The above page also lists the current membership of the OSO Time Allocation Committee (evaluating APEX and 20 m telescope proposals) and the LOFAR-Sweden time allocations committee which provides input to the international LOFAR time allocation process.

14 Importance to society

Onsala Space Observatory supports basic research within astronomy and geoscience. Both astronomy and geoscience research have a strong appeal to the curiosity of people of all ages, and this is used in our outreach activities as described above. In addition, geoscience is of importance for understanding the system “Earth”, and therefore of importance for e.g. climate applications, such as monitoring of ozone in the atmosphere and determining changes in the absolute sea level. Geodetic VLBI provides the fundamental terrestrial reference frame, which is the basis for all navigational applications. As a by-product of its VLBI activities, the observatory also contributes to establishing the official Swedish time and international time, through two hydrogen maser clocks and one cesium clock. The OSO staff and instruments are also involved in education at all levels from bachelor to graduate studies at Chalmers, and through organised schools.

15 Importance to industry

Currently the major industrial impact of OSO’s work is connected with the SKA project. The SKA is on such a scale that its components must be provided by industry. The planned for Swedish involvement in SKA construction will have a large financial payback to Swedish companies. During 2020 Patrik Carlsson of Chalmers Industrial Technology and Big Science Sweden continued to fulfil the Swedish SKA Industrial Liaison Officer (ILO) role. Big Science Sweden (https://www.bigsciencesweden.se) is an organisation which promotes technological and industrial return to Sweden from international Big Science infrastructures. During 2020 Chalmers Level 1 leadership of the SKA1-mid Band 1 and SKA1-mid Digitizer work packages was confirmed. During the year discussions led by CIT have occurred

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with several Swedish companies that could act as prime contractors for supplying Band 1 while a competative procurement led to the selection the Quamcom company for work on industrialization of the SKA-mid Band 1,2,3 Digitizer design. Separate procurements for Digitizer production will be made in the coming years. In addition, a Swedish company (Low Noise Factory) will be a Level 2 supplier of Low Noise Amplifiers to other receiver bands in addition to Band 1. Another potential future area of industrial involvement in SKA is in AI and machine learning, in which Chalmers has a leading position within Sweden. OSO started involvement in this area by executing a joint project with Chalmers Fraunhofer Centre of Industrial Mathemetics on ML supported automatic source finding in simulated SKA data. Some of the technical developments for SKA (in Digitizers and AI/ML) also have the potential to provide future industrial return as part of a planned upgrade of ALMA which is planned to be completed by 2030.

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Acronyms

A&A Astronomy & Astrophysics (a scientific journal) ACA Atacama Compact Array AETHRA Advanced European Technologies for Heterodyne Receivers for Astronomy (part of RadioNet) AGB Asymptotic Giant Branch (AGB stars are giant evolved stars) AGN AI Artificial Intelligence ALMA Atacama Large Millimeter/ (Chile) APEX Atacama Pathfinder Experiment (Chile) ApJ Astrophysical Journal (a scientific journal) ARC ALMA Regional Centre ASTRON Netherlands Institute for Radio Astronomy AU Astronomical Unit (the distance between the Sun and Earth)

BRAND BRoad bAND EVN (part of RadioNet)

C3SE Chalmers Centre for Computational Science and Engineering CEPT European Conference of Postal and Telecommunications Administrations Correspondance Group CIT Chalmers Industrial Technology CO Carbon monoxide (molecule frequently observed by radio telescopes) CRAF Committee on Radio Astronomy Frequencies (ESF)

DBBC Digital Base Band Converter (equipment for VLBI observations)

EAS European Astronomical Society EC European Commission ERIC European Research Infrastructure Consortium ESO European Southern Observatory EUREF IAG Reference Frame Sub-Commission for Europe EVGA The European VLBI Group for Geodesy and Astrometry EVN European VLBI Network

FRB Fast radio burst FTE Full-time equivalent

GARD Group for Advanced Receiver Development (part of OSO) GMVA Global Millimeter VLBI Array GNSS Global Navigational Satellite Systems GPS Global Positioning System GPU Graphics Processor Unit GSAC Galileo Scientific Advisory Committee of the European Space Agency

HMXB High-mass X-ray binary HST Hubble Space Telescope

IAG The International Association of Geodesy IAU International Astronomical Union

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ICCC Inter-Commission Committee on Geodesy for Climate Research ICCM Inter-Commission Committee on Marine Geodesy ICRF International Celestial Reference Frame ICSU International Council for Science IERS International Earth Rotation and Reference Frame Service IF Intermediate frequency IGETS International Geodynamics and Earth Tide Service IGO Inter-governmental organisation IGS The International GNSS Service ILO Industrial Liaison Officer ILT International LOFAR Telescope IMBH Intermediate mass I-TRAIN Interactive Training in Reduction and Analysis of INterferometric data (activity within the European ARC Network) ITRF International Terrestrial Reference Frame ITU International Telecommunication Union IVS International VLBI Service for Geodesy and Astrometry

JIVE Joint Institute for VLBI in Europe (NL) JRA Joint Research Activity (part of RadioNet)

LOFAR Low Frequency Array LOFAR4SW LOFAR for Space Weather (EU Horizon 2020 project) mas milliarcsecond MC2 Department of Microtechnology and Nanoscience at Chalmers ML Machine Learning MNRAS Monthly Notices of the Royal Astronomical Society (a scientific journal) MWA Murchison Widefield Array

NDACC Network for the Detection of Atmospheric Composition Change NOVA Nederlandse Onderzoekschool Voor Astronomie (The Netherlands Research School for Astronomy)

ODP Observatory Development Programme (for SKA) OSO Onsala Space Observatory OTT Onsala Twin Telescope

PI Principal Investigator

RadioNet Advanced Radio Astronomy in Europe (EU Horizon 2020 project) RFI Radio Frequency Interference RINGS Radio Interferometry Next Generation Software (part of RadioNet) RISE Research Institutes of Sweden

SALSA Small antennas at OSO for education and outreach SCG Superconducting Gravimeter SEE Department of Space, Earth and Environment (OSO’s host department at Chalmers) SEPIA Swedish ESO PI receiver for APEX

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SEST Swedish-ESO Submillimetre Telescope (Chile) SKA Square Kilometre Array SKAO Square Kilometre Array Organisation SLR Satellite Laser Ranging SMBH Supermassive black hole SMHI Sveriges meteorologiska och hydrologiska institut (Swedish Meteorological and Hydrological Institute) SNIC Swedish National Infrastructure for Computing SNR Signal-to-Noise Ratio SNSN Svenska nationella seismiska nätverket SRC SKA Regional Centre SUNET Swedish University Computer Network SWEPOS The Swedish permanent GNSS network, hosted by Lantmäteriet

TAC Time Allocation Committee TDE Tidal Disruption Event TEC Total Electron Content TG Tide gauge

UT1 The principal form of Universal Time (which is based on Earth’s rotation) UTC Coordinated Universal Time (an atomic timescale that approximates UT1)

VGOS VLBI Geodetic Observing System VINNOVA Sweden’s innovation agency VLBA Very Long Baseline Array VLBI Very Long Baseline Interferometry VR Vetenskapsrådet, The Swedish Research Council

WDS World Data System, an Interdisciplinary Body of the International Council for Science (ICSU) WP Work Package

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Publications 2020

This section lists publications in refereed journals 2020 enabled by the Onsala infrastructure, divided by instrument and separated in two groups: with or without a Swedish author. For more detailed information about the publication list, see Sect. 2.1. The number of publications per instrument is given below. Two figures are given: total number of publications/number of publications with at least one Swedish author (for ALMA, the first figure is instead the number of papers with at least one Nordic author).

• ALMA observations, publications with Nordic authors (82/46) (Nordic/Swedish) thereof with explicit Nordic ARC node support (17/13) (Nordic/Swedish) • APEX observations (all APEX partners’ observing time) (67/5) (total/Swedish) • Astronomical VLBI obs. w. EHT, EVN or GMVA, or using JIVE (30/13) (total/Swedish) • LOFAR observations (77/9) (total/Swedish) • Geoscience (OSO instruments specifically stated) (23/8) (total/Swedish) • Onsala 20 m telescope, single-dish observations (6/2) (total/Swedish) • Technical publications about, e.g., receiver development, by OSO staff (8)

In addition to the publications listed below, in 2020 there was 1 publication using astronomical data from the satellite Odin (now operating mainly in aeronomy mode), and 5 publications using data from the Swedish-ESO Submillimetre Telescope SEST (closed in 2003).

Note: - The publications are separated in two groups: with or without a Swedish author - In each section, the references are sorted by first author. - An excel file with the publications is provided separately. - For information about the level of ARCnode support for the ALMA publications, see the separate excel file. - For information about which of the APEX publications are based on observations on Swedish time, see the separate excel file.

Acronyms: A&A Astronomy & Astrophysics Adv. Space Res. Advances in Space Research AJ Astronomical Journal ApJ Astrophysical Journal Astropart. Phys. Astroparticle Physcis JCAP Journal of Cosmology and Astroparticle Physics J. Geod. Journal of Geodesy JSTARS IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing JSWSC Journal of Space Weather and Space Climate MNRAS Monthly Notices of the Royal Astronomical Society PASA Publications of the Astronomical Society of Australia PASP Publications of the Astronomical Society of the Pacific Phys. Rev. Lett. Physical Review Letters Publ. DGPF Publikationen der Deutschen Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation (DGPF) e.V. Space Sci. Rev. Space Science Reviews

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ALMA, publications in refereed journals 2020, with Nordic authors

Swedish authors (ALMA)

ALMA resolves the remarkable molecular jet and rotating wind in the extremely radio-quiet galaxy NGC 1377. Aalto, S., Falstad, N., Muller, S., Wada, K., Gallagher, J. S., König, S., Sakamoto, K., Vlemmings, W., Ceccobello, C., Dasyra, K., Combes, F., Garcia-Burillo, S., Oya, Y., Martin, S., van der Werf, P., Evans, A. S., & Kotilainen, J. A&A 640, A104 (2020)

ALMA uncovers the [C II] emission and warm dust continuum in a z = 8.31 Lyman break galaxy. Bakx, T. J. L. C., Tamura, Y., Hashimoto, T., Inoue, A. K., Lee, M. M., Mawatari, K., Ota, K., Umehata, H., Zackrisson, E., Hatsukade, B., Kohno, K., Matsuda, Y., Matsuo, H., Okamoto, T., Shibuya, T., Shimizu, I., Taniguchi, Y., & Yoshida, N. MNRAS 493, 4294 (2020)

Gravity and Rotation Drag the Magnetic Field in High-mass Star Formation. Beuther, H., Soler, J. D., Linz, H., Henning, T., Gieser, C., Kuiper, R., Vlemmings, W., Hennebelle, P., Feng, S., Smith, R., & Ahmadi, A. ApJ 904, 168 (2020)

The Surprisingly Low Carbon Mass in the Debris Disk around HD 32297. Cataldi, G., Wu, Y., Brandeker, A., Ohashi, N., Moor, A., Olofsson, G., Abraham, P., Asensio-Torres, R., Cavallius, M., Dent, W. R. F., Grady, C., Henning, T., Higuchi, A. E., Hughes, A. M., Janson, M., Kamp, I., Kospal, A., Redfield, S., Roberge, A., Weinberger, A., & Welsh, B. ApJ 892, 99 (2020)

Gas Kinematics of the Massive Protocluster G286.21+0.17 Revealed by ALMA. Cheng, Y., Tan, J. C., Liu, M., Lim, W., & Andersen, M. ApJ 894, 87 (2020)

The multi-thermal chromosphere. Inversions of ALMA and IRIS data. da Silva Santos, J. M., de la Cruz Rodriguez, J., Leenaarts, J., Chintzoglou, G., De Pontieu, B., Wedemeyer, S., & Szydlarski, M. A&A 634, A56 (2020)

ALMA observations of transient heating in a solar active region. da Silva Santos, J. M., de la Cruz Rodriguez, J., White, S. M., Leenaarts, J., Vissers, G. J. M., & Hansteen, V. H. A&A 643, A41 (2020)

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Ultracompact H II regions with extended emission: the case of G43.89-0.78 and its molecular environment. de la Fuente, Eduardo; Tafoya, Daniel; Trinidad, Miguel A.; Porras, Alicia; Nigoche-Netro, Alberto; Kemp, Simon N.; Kurtz, Stanley E.; Franco, José; Rodríguez-Rico, Carlos A. MNRAS 497, 4436 (2020)

(Sub)stellar companions shape the winds of evolved stars. Decin, L., Montarges, M., Richards, A. M. S., Gottlieb, C. A., Homan, W., McDonald, I., El Mellah, I., Danilovich, T., Wallström, S. H. J., Zijlstra, A., Baudry, A., Bolte, J., Cannon, E., De Beck, E., De Ceuster, F., de Koter, A., De Ridder, J., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Lagadec, E., Kervella, P., Khouri, T., Menten, K., Millar, T. J., Müller, H. S. P., Plane, J. M. C., Sahai, R., Sana, H., Van de Sande, M., Waters, L. B. F. M., Wong, K. T., & Yates, J. Science 369, 1497 (2020)

The extended molecular envelope of the asymptotic giant branch star π1 Gruis as seen by ALMA. II. The spiral-outflow observed at high-angular resolution. Doan, L., Ramstedt, S., Vlemmings, W. H. T., Mohamed, S., Höfner, S., De Beck, E., Kerschbaum, F., Lindqvist, M., Maercker, M., Paladini, C., & Wittkowski, M. A&A 633, A13 (2020)

Super Star Clusters in the Central Starburst of NGC 4945. Emig, K. L., Bolatto, A. D., Leroy, A. K., Mills, E. A. C., Jiminez Donaire, M. J., Tielens, A.G.G.M., Ginsburg, A., Gorski, M., Krieger, N., Levy, R. C., Meier, D. S., Ott, J., Rosolowsky, E., Thompson, T. A., & Veilleux, S. ApJ 903, 50 (2020)

A CO molecular gas wind 340 pc away from the Seyfert 2 nucleus in ESO 420-G13 probes an elusive radio jet. Fernandez-Ontiveros, J. A., Dasyra, K. M., Hatziminaoglou, E., Malkan, M. A., Pereira- Santaella, M., Papachristou, M., Spinoglio, L., Combes, F., Aalto, S., Nagar, N., Imanishi, M., Andreani, P., Ricci, C., & Slater, R. A&A 633, A127 (2020)

SMM J04135+10277: a distant QSO-starburst system caught by ALMA. Fogasy, J., Knudsen, K. K., Drouart, G., Lagos, C. D. P., & Fan, L. MNRAS 493, 3744 (2020)

Gas kinematics of key prebiotic molecules in GV Tau N revealed with an ALMA, PdBI, and Herschel synergy. Fuente, A., Trevino-Morales, S. P., Le Gal, R., Riviere-Marichalar, P., Pilleri, P., Rodriguez- Baras, M., & Navarro-Almaida, D. MNRAS 496, 5330 (2020)

Verification of Radiative Transfer Schemes for the EHT. Gold, R., Broderick, A. E., Younsi, Z., Fromm, C. M., Gammie, C. F., Moscibrodzka, M., Pu, H.-Y., Bronzwaer, T., Davelaar, J., Dexter, J., Ball, D., Chan, C.-.kwan ., Kawashima, T., Mizuno, Y., Ripperda, B., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S.,

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Broguiere, D., Byun, D.-Y., Carlstrom, J. E., Chael, A., Chatterjee, K., Chatterjee, S., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Freeman, B., Friberg, P., Gomez, J. L., Galison, P., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C.-W. L., Huang, L., Hughes, D. H., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Keating, G. K., Kettenis, M., Kim, J.-Y., Kim, J., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C.-Y., Lauer, T. R., Lee, S.-S., Li, Y.-R., Li, Z., Lico, R., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W.-P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R.-S., MacDonald, N. R., Markoff, S., Mao, J., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, I., Moran, J. M., Moriyama, K., Müller, C., Nagai, H., Nakamura, M., Nagar, N. M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Ortiz-Leon, G. N., Oyama, T., Özel, F., Palumbo, D. C. M., Park, J., Patel, N., Pen, U.-L., Pesce, D. W., Plambeck, R., Pietu, V., PopStefanija, A., Porth, O., Preciado-Lopez, J. A., Psaltis, D., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schuster, K. F., Schloerb, F. P., Shao, L., Shen, Z., Small, D., Sohn, B. W., SooHoo, J., Tiede, P., Tazaki, F., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, T., Trippe, S., Tsuda, S., van Langevelde, H. J., van Bemmel, I., van Rossum, D. R., Wagner, J., Wardle, J., Wex, N., Weintroub, J., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Yoon, D., Young, K., Young, A., Yuan, F., Yuan, Y.-F., Zensus, J. A., Zhao, G., Zhao, S.-S., Zhu, Z., & Collaboration. ApJ 897, 148 (2020)

Missing water in Class I protostellar disks. Harsono, D., Persson, M. V., Ramos, A., Murillo, N. M., Maud, L. T., Hogerheijde, M. R., Bosman, A. D., Kristensen, L. E., Jørgensen, J. K., Bergin, E. A., Visser, R., Mottram, J. C., & van Dishoeck, E. F. A&A 636, A26 (2020)

Mapping Circumstellar Magnetic Fields of Late-type Evolved Stars with the Goldreich- Kylafis Effect: CARMA Observations at λ1.3 mm of R Crt and R Leo. Huang, K.-Y., Kemball, A. J., Vlemmings, W. H. T., Lai, S.-P., Yang, L., & Agudo, I. ApJ 899, 152 (2020)

ALMA 0"02 Resolution Observations Reveal HCN-abundance-enhanced Counter-rotating and Outflowing Dense Molecular Gas at the NGC 1068 Nucleus. Imanishi, M., Nguyen, D. D., Wada, K., Hagiwara, Y., Iguchi, S., Izumi, T., Kawakatu, N., Nakanishi, K., & Onishi, K. ApJ 902, 99 (2020)

AGN X-Ray Irradiation of CO Gas in NGC 2110 Revealed by Chandra and ALMA. Kawamuro, T., Izumi, T., Onishi, K., Imanishi, M., Nguyen, D. D., & Baba, S. ApJ 895, 135 (2020)

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Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution. Kim, J.-Y., Krichbaum, T. P., Broderick, A. E., Wielgus, M., Blackburn, L., Gomez, J. L., Johnson, M. D., Bouman, K. L., Chael, A., Akiyama, K., Jorstad, S., Marscher, A. P., Issaoun, S., Janssen, M., Chan, C.-.kwan., Savolainen, T., Pesce, D. W., Özel, F., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Boland, W., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D.-Y., Carlstrom, J. E., Chatterjee, S., Chatterjee, K., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga- Encinas, R., Friberg, P., Fromm, C. M., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gomez-Ruiz, A. I., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C.-W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., James, D. J., Jannuzi, B. T., Jeter, B., Jiang, W., Jimenez- Rosales, A., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C.-Y., Lauer, T. R., Lee, S.-S., Li, Y.-R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W.-P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R.-S., MacDonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Musoke, G., Müller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Palumbo, D. C. M., Park, J., Patel, N., Pen, U.-L., Pietu, V., Plambeck, R., PopStefanija, A., Porth, O., Prather, B., Preciado- Lopez, J. A., Psaltis, D., Pu, H.-Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A.W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Schloerb, F. P., Schuster, K.-F., Shao, L., Shen, Z., Small, D., Sohn, B. W., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R.P.J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Wardle, J., Ward-Thompson, D., Weintroub, J., Wex, N., Wharton, R., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y.-F., Zensus, J. A., Zhao, G., Zhao, S.-S., Zhu, Z., Algaba, J.-C., Allardi, A., Amestica, R., Anczarski, J., Bach, U., Baganoff, F. K., Beaudoin, C., Benson, B. A., Berthold, R., Blanchard, J. M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Dominguez, E., Chang, C.-C., Chang, S.-H., Chang, S.-C., Chen, C.-C., Chilson, R., Chuter, T.C., Rosado, R. C., Coulson, I. M., Crowley, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K. A., Dzib, S. A., Eckart, A., Eckert, C., Erickson, N. R., Everett, W. B., Faber, A., Farah, J. R., Fath, V., Folkers, T. W., Forbes, D. C., Freund, R., Gale, D. M., Gao, F., Geertsema, G., Graham, D. A., Greer, C. H., Grosslein, R., Gueth, F., Haggard, D., Halverson, N. W., Han, C.-C., Han, K.-C., Hao, J., Hasegawa, Y., Henning, J.W., Hernandez-Gomez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y.-D., Violette Impellizzeri, C. M., Jiang, H., John, D., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R. A., Leitch, E.M., Li, C.T., Lin, L. C.-C., Liu, C.-T., Liu, K.-Y., Lu, L.-M., Marson, R. G., Martin-Cocher, P. L., Massingill, K. D., Matulonis, C., McColl, M. P., McWhirter, S. R., Messias, H., Meyer- Zhao, Z., Michalik, D., Montana, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Neilsen, J., Nguyen, C. H., Nishioka, H., Norton, T., Nowak, M.A., Nystrom, G., Ogawa, H., Oshiro, P., Oyama, T., Parsons, H., Penalver, J., Phillips, N. M.,

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Poirier, M., Pradel, N., Primiani, R. A., Raffin, P. A., Rahlin, A. S., Reiland, G., Risacher, C., Ruiz, I., Saez-Madain, A. F., Sassella, R., Schellart, P., Shaw, P., Silva, K. M., Shiokawa, H., Smith, D. R., Snow, W., Souccar, K., Sousa, D., Sridharan, T. K., Srinivasan, R., Stahm, W., Stark, A. A., Story, K., Timmer, S. T., Vertatschitsch, L., Walther, C., Wei, T.-S., Whitehorn, N., Whitney, A. R., Woody, D. P., Wouterloot, J. G. A., Wright, M., Yamaguchi, P., Yu, C.-Y., Zeballos, M., Zhang, S., Ziurys, L., & Event Horizon Telescope Collaboration. A&A 640, A69 (2020)

The ALMA Survey of 70 um Dark High-mass Clumps in Early Stages (ASHES). II. Molecular Outflows in the Extreme Early Stages of Protocluster Formation. Li, S., Sanhueza, P., Zhang, Q., Nakamura, F., Lu, X., Wang, J., Liu, T., Tatematsu, K., Jackson, J. M., Silva, A., Guzman, A. E., Sakai, T., Izumi, N., Tafoya, D., Li, F., Contreras, Y., Morii, K., & Kim, K.-T. ApJ 903, 119 (2020)

Atacama Compact Array observations of the pulsar-wind of SNR 0540-69.3. Lundqvist, P., Lundqvist, N., Vlahakis, C., Björnsson, C.-I., Dickel, J. R., Matsuura, M., Shibanov, Y. A., Zyuzin, D. A., & Olofsson, G. MNRAS 496, 1834 (2020)

Molecular outflows in local galaxies: Method comparison and a role of intermittent AGN driving. Lutz, D., Sturm, E., Janssen, A., Veilleux, S., Aalto, S., Cicone, C., Contursi, A., Davies, R. I., Feruglio, C., Fischer, J., Fluetsch, A., Garcia-Burillo, S., Genzel, R., Gonzalez- Alfonso, E., Gracia-Carpio, J., Herrera-Camus, R., Maiolino, R., Schruba, A., Shimizu, T., Sternberg, A., Tacconi, L. J., & Weiß, A. A&A 633, A134 (2020)

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293- 2422 A. Manigand, S., Jørgensen, J. K., Calcutt, H., Müller, H. S. P., Ligterink, N. F. W., Coutens, A., Drozdovskaya, M. N., van Dishoeck, E. F., & Wampfler, S. F. A&A 635, A48 (2020)

The Formation Height of Millimeter-wavelength Emission in the Solar Chromosphere. Martinez-Sykora, J., De Pontieu, B., de la Cruz Rodriguez, J., & Chintzoglou, G. ApJ 891, L8 (2020)

ALMA full polarization observations of PKS 1830-211 during its record-breaking flare of 2019. Marti-Vidal, I., Muller, S., Mus, A., Marscher, A., Agudo, I., & Gomez, J. L. A&A 638, L13 (2020)

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VALES VI: ISM enrichment in star-forming galaxies up to z≈0.2 using 12CO(1-0), 13CO(1-0), and C18O(1-0) line luminosity ratios. Mendez-Hernandez, H., Ibar, E., Knudsen, K. K., Cassata, P., Aravena, M., Michalowski, M. J., Zhang, Z.-Y., Lara-Lopez, M. A., Ivison, R. J., van der Werf, P., Villanueva, V., Herrera-Camus, R., & Hughes, T. M. MNRAS 497, 2771 (2020)

All good things come in threes: the third image of the lensed quasar PKS 1830-211. Muller, S., Jaswanth, S., Horellou, C., & Marti-Vidal, I. A&A 641, L2 (2020)

Detection of deuterated molecules, but not of lithium hydride, in the z = 0.89 absorber toward PKS 1830-211. Muller, S., Roueff, E., Black, J. H., Gerin, M., Guelin, M., Menten, K. M., Henkel, C., Aalto, S., Combes, F., Martin, S., & Marti-Vidal, I. A&A 637, A7 (2020)

Spirals inside the millimeter cavity of transition disk SR 21. Muro-Arena, G. A., Ginski, C., Dominik, C., Benisty, M., Pinilla, P., Bohn, A. J., Moldenhauer, T., Kley, W., Harsono, D., Henning, T., van Holstein, R. G., Janson, M., Keppler, M., Menard, F., Perez, L. M., Stolker, T., Tazzari, M., Villenave, M., Zurlo, A., Petit, C., Rigal, F., Möller-Nilsson, O., Llored, M., Moulin, T., & Rabou, P. A&A 636, L4 (2020)

ALMA and VLA reveal the lukewarm chromospheres of the nearby red supergiants Antares and . O'Gorman, E., Harper, G. M., Ohnaka, K., Feeney-Johansson, A., Wilkeneit-Braun, K., Brown, A., Guinan, E. F., Lim, J., Richards, A. M. S., Ryde, N., & Vlemmings, W. H. T. A&A 638, A65 (2020)

Cold molecular gas and free-free emission from hot, dust-obscured galaxies at z ~ 3. Penney, J. I., Blain, A. W., Assef, R. J., Diaz-Santos, T., Gonzalez-Lopez, J., Tsai, C.-W., Aravena, M., Eisenhardt, P. R. M., Jones, S. F., Jun, H. D., Kim, M., Stern, D., & Wu, J. MNRAS 496, 1565 (2020)

DEATHSTAR: Nearby AGB stars with the Atacama Compact Array. I. CO envelope sizes and asymmetries: A new hope for accurate mass-loss-rate estimates. Ramstedt, S., Vlemmings, W. H. T., Doan, L., Danilovich, T., Lindqvist, M., Saberi, M., Olofsson, H., De Beck, E., Groenewegen, M. A. T., Höfner, S., Kastner, J. H., Kerschbaum, F., Khouri, T., Maercker, M., Montez, R., Quintana-Lacaci, G., Sahai, R., Tafoya, D., & Zijlstra, A. A&A 640, A133 (2020)

Discovery of a complex spiral-shell structure around the oxygen-rich AGB star GX Monocerotis. Randall, S. K., Trejo, A., Humphreys, E. M. L., Kim, H., Wittkowski, M., Boboltz, D., & Ramstedt, S. A&A 636, A123 (2020)

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Characterizing the radio continuum nature of sources in the massive star-forming region W75N (B). Rodriguez-Kamenetzky, A., Carrasco-Gonzalez, C., Torrelles, J. M., Vlemmings, W. H. T., Rodriguez, L. F., Surcis, G., Gomez, J. F., Canto, J., Goddi, C., Kim, J. S., Kim, S.-W., Anez- Lopez, N., Curiel, S., & van Langevelde, H. J. MNRAS 496, 3128 (2020)

SYMBA: An end-to-end VLBI synthetic data generation pipeline. Simulating Event Horizon Telescope observations of M 87. Roelofs, F., Janssen, M., Natarajan, I., Deane, R., Davelaar, J., Olivares, H., Porth, O., Paine, S. N., Bouman, K. L., Tilanus, R. P. J., van Bemmel, I. M., Falcke, H., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D., Carlstrom, J. E., Chael, A., Chan, C., Chatterjee, S., Chatterjee, K., Chen, M., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., De Laurentis, M., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J., Kim, J., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C., Lauer, T. R., Lee, S., Li, Y., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R., MacDonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Müller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Özel, F., Palumbo, D. C. M., Patel, N., Pen, U., Pesce, D. W., Pietu, V., Plambeck, R., PopStefanija, A., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K., Shao, L., Shen, Z., Small, D., Won Sohn, B., SooHoo, J., Tazaki, F., Tiede, P., Titus, M., Toma, K., Torne, P., Traianou, E., Trent, T., Trippe, S., Tsuda, S., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y., Zensus, J. A., Zhao, G., Zhao, S., & Zhu, Z. A&A 636, A5 (2020)

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Rapid compact jet quenching in the Galactic black hole candidate X-ray binary MAXI J1535- 571. Russell, T. D., Lucchini, M., Tetarenko, A. J., Miller-Jones, J. C. A., Sivakoff, G. R., Krauß, F., Mulaudzi, W., Baglio, M. C., Russell, D. M., Altamirano, D., Ceccobello, C., Corbel, S., Degenaar, N., van den Eijnden, J., Fender, R., Heinz, S., Koljonen, K. I. I., Maitra, D., Markoff, S., Migliari, S., Parikh, A. S., Plotkin, R. M., Rupen, M., Sarazin, C., Soria, R., & Wijnands, R. MNRAS 498, 5772 (2020)

ALMA observations of CS in NGC 1068: chemistry and excitation. Scourfield, M., Viti, S., Garcia-Burillo, S., Saintonge, A., Combes, F., Fuente, A., Henkel, C., Alonso-Herrero, A., Harada, N., Takano, S., Nakajima, T., Martin, S., Krips, M., van der Werf, P. P., Aalto, S., Usero, A., & Kohno, K. MNRAS 496, 5308 (2020)

Shaping the Envelope of the Asymptotic Giant Branch Star W43A with a Collimated Fast Jet. Tafoya, D., Imai, H., Gomez, J. F., Nakashima, J.-. ichi ., Orosz, G., & Yung, B. H. K. ApJ 890, L14 (2020)

Salt, Hot Water, and Silicon Compounds Tracing Massive Twin Disks. Tanaka, K. E. I., Zhang, Y., Hirota, T., Sakai, N., Motogi, K., Tomida, K., Tan, J. C., Rosero, V., Higuchi, A. E., Ohashi, S., Liu, M., & Sugiyama, K. ApJ 900, L2 (2020)

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Protostars. II. A Statistical Characterization of Class 0 and Class I Protostellar Disks. Tobin, J. J., Sheehan, P. D., Megeath, S. T., Diaz-Rodriguez, A. K., Offner, S. S. R., Murillo, N. M., van 't Hoff, M. L. R., van Dishoeck, E. F., Osorio, M., Anglada, G., Furlan, E., Stutz, A. M., Reynolds, N., Karnath, N., Fischer, W. J., Persson, M., Looney, L. W., Li, Z.-Y., Stephens, I., Chandler, C. J., Cox, E., Dunham, M. M., Tychoniec, L., Kama, M., Kratter, K., Kounkel, M., Mazur, B., Maud, L., Patel, L., Perez, L., Sadavoy, S. I., Segura-Cox, D., Sharma, R., Stephenson, B., Watson, D. M., & Wyrowski, F. ApJ 890, 130 (2020)

Temperature profiles of young disk-like structures. The case of IRAS 16293A. van 't Hoff, M. L. R., van Dishoeck, E. F., Jørgensen, J. K., & Calcutt, H. A&A 633, A7 (2020)

The Sun at millimeter wavelengths. I. Introduction to ALMA Band 3 observations. Wedemeyer, S., Szydlarski, M., Jafarzadeh, S., Eklund, H., Guevara Gomez, J. C., Bastian, T., Fleck, B., de la Cruz Rodriguez, J., Rodger, A., & Carlsson, M. A&A 635, A71 (2020)

Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope. Wielgus, M., Akiyama, K., Blackburn, L., Chan, C.-. kwan ., Dexter, J., Doeleman, S. S., Fish, V. L., Issaoun, S., Johnson, M. D., Krichbaum, T. P., Lu, R.-S., Pesce, D. W., Wong, G. N., Bower, G. C., Broderick, A. E., Chael, A., Chatterjee, K., Gammie, C. F., Georgiev, B., Hada, K., Loinard, L., Markoff, S., Marrone, D. P., Plambeck, R., Weintroub, J., Dexter, M., MacMahon, D. H. E., Wright, M., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Ball, D., Balokovic, M., Barausse, E., Barrett, J.,

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Bintley, D., Boland, W., Bouman, K. L., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D.-Y., Carlstrom, J. E., Chatterjee, S., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., Laurentis, M. D., Deane, R., Dempsey, J., Desvignes, G., Dzib, S. A., Eatough, R. P., Falcke, H., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Galison, P., Garcia, R., Gentaz, O., Goddi, C., Gold, R., Gomez, J. L., Gomez-Ruiz, A. I., Gu, M., Gurwell, M., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. W. L., Huang, L., Hughes, D. H., Inoue, M., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J.-Y., Kim, J., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C.-Y., Lauer, T. R., Lee, S.-S., Li, Y.-R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W. P., Lobanov, A. P., Lonsdale, C., MacDonald, N. R., Mao, J., Marchili, N., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Müller, C., Musoke, G., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz- Leon, G. N., Oyama, T., Özel, F., Palumbo, D. C. M., Park, J., Patel, N., Pen, U.-L., Pietu, V., PopStefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H.-Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. F., Shao, L., Shen, Z., Small, D., Sohn, B. W., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., Bemmel, I. van ., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Wardle, J., Ward-Thompson, D., Wex, N., Wharton, R., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y.-F., Zensus, J. A., Zhao, G., Zhao, S.-S., & Zhu, Z. ApJ 901, 67 (2020)

High-resolution Near-infrared Polarimetry and Submillimeter Imaging of FS Tau A: Possible Streamers in Misaligned Circumbinary Disk System. Yang, Y., Akiyama, E., Currie, T., Dong, R., Hashimoto, J., Hayashi, S. S., Grady, C. A., Janson, M., Jovanovic, N., Uyama, T., Nakagawa, T., Kudo, T., Kusakabe, N., Kuzuhara, M., Abe, L., Brandner, W., Brandt, T. D., Bonnefoy, M., Carson, J. C., Chilcote, J., Rich, E. A., Feldt, M., Goto, M., Groff, T. D., Guyon, O., Hayano, Y., Hayashi, M., Henning, T., Hodapp, K. W., Ishii, M., Iye, M., Kandori, R., Kasdin, J., Knapp, G. R., Kwon, J., Lozi, J., Martinache, F., Matsuo, T., Mayama, S., Mcelwain, M. W., Miyama, S., Morino, J.-I., Moro- Martin, A., Nishimura, T., Pyo, T.-S., Serabyn, E., Suto, H., Suzuki, R., Takami, M., Takato, N., Terada, H., Thalmann, C., Turner, E. L., Watanabe, M., Wisniewski, J. P., Yamada, T., Takami, H., Usuda, T., & Tamura, M. ApJ 889, 140 (2020)

Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and Its Hot Corino. Yang, Y.-L., Evans, N. J., Smith, A., Lee, J.-E., Tobin, J. J., Terebey, S., Calcutt, H., Jørgensen, J. K., Green, J. D., & Bourke, T. L. ApJ 891, 61 (2020)

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Nordic authors (ALMA)

Infalling gas in a Lyman-alpha blob. Ao, Y., Zheng, Z., Henkel, C., Nie, S., Beelen, A., Cen, R., Dijkstra, M., Francis, P. J., Geach, J. E., Kohno, K., Lehnert, M. D., Menten, K. M., Wang, J., & Weiss, A. Nature Astronomy 4, 670 (2020)

The ALPINE-ALMA [CII] survey: Data processing, catalogs, and statistical source properties. Bethermin, M., Fudamoto, Y., Ginolfi, M., Loiacono, F., Khusanova, Y., Capak, P. L., Cassata, P., Faisst, A., Le Fevre, O., Schaerer, D., Silverman, J. D., Yan, L., Amorin, R., Bardelli, S., Boquien, M., Cimatti, A., Davidzon, I., Dessauges-Zavadsky, M., Fujimoto, S., Gruppioni, C., Hathi, N. P., Ibar, E., Jones, G. C., Koekemoer, A. M., Lagache, G., Lemaux, B. C., Moreau, C., Oesch, P. A., Pozzi, F., Riechers, D. A., Talia, M., Toft, S., Vallini, L., Vergani, D., Zamorani, G., & Zucca, E. A&A 643, A2 (2020)

The [C II]/[N II] ratio in 3 < z < 6 sub-millimetre galaxies from the South Pole Telescope survey. Cunningham, D. J. M., Chapman, S. C., Aravena, M., De Breuck, C., Bethermin, M., Chen, C.-C., Dong, C., Gonzalez, A. H., Greve, T. R., Litke, K. C., Ma, J., Malkan, M., Marrone, D. P., Miller, T., Phadke, K. A., Reuter, C., Rotermund, K., Spilker, J. S., Stark, A. A., Strandet, M., Vieira, J. D., & Weiß, A. MNRAS 494, 4090 (2020)

GRB 190114C in the nuclear region of an interacting galaxy. A detailed host analysis using ALMA, the HST, and the VLT. de Ugarte Postigo, A., Thöne, C. C., Martin, S., Japelj, J., Levan, A. J., Michalowski, M. J., Selsing, J., Kann, D. A., Schulze, S., Palmerio, J. T., Vergani, S. D., Tanvir, N. R., Bensch, K., Covino, S., D'Elia, V., De Pasquale, M., Fruchter, A. S., Fynbo, J. P. U., Hartmann, D., Heintz, K. E., van der Horst, A. J., Izzo, L., Jakobsson, P., Ng, K. C. Y., Perley, D. A., Rossi, A., Sbarufatti, B., Salvaterra, R., Sanchez-Ramirez, R., Watson, D., & Xu, D. A&A 633, A68 (2020)

In pursuit of giants. I. The evolution of the dust-to-stellar mass ratio in distant dusty galaxies. Donevski, D., Lapi, A., Malek, K., Liu, D., Gomez-Guijarro, C., Dave, R., Kraljic, K., Pantoni, L., Man, A., Fujimoto, S., Feltre, A., Pearson, W., Li, Q., & Narayanan, D. A&A 644, A144 (2020)

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP). II. Survey Overview: A First Look at 1.3 mm Continuum Maps and Molecular Outflows. Dutta, S., Lee, C.-F., Liu, T., Hirano, N., Liu, S.-Y., Tatematsu, K., Kim, K.-T., Shang, H., Sahu, D., Kim, G., Moraghan, A., Jhan, K.-S., Hsu, S.-Y., Evans, N. J., Johnstone, D., Ward- Thompson, D., Kuan, Y.-J., Lee, C. W., Lee, J.-E., Traficante, A., Juvela, M., Vastel, C., Zhang, Q., Sanhueza, P., Soam, A., Kwon, W., Bronfman, L., Eden, D., Goldsmith, P. F., He, J., Wu, Y., Pelkonen, V.-M., Qin, S.-L., Li, S., & Li, D. ApJ Supplement Series 251, 20 (2020)

52

The Sun at millimeter wavelengths. II. Small-scale dynamic events in ALMA Band 3. Eklund, H., Wedemeyer, S., Szydlarski, M., Jafarzadeh, S., & Guevara Gomez, J. C. A&A 644, A152 (2020)

ALMA characterizes the dust temperature of z ~ 5.5 star-forming galaxies. Faisst, A. L., Fudamoto, Y., Oesch, P. A., Scoville, N., Riechers, D. A., Pavesi, R., & Capak, P. MNRAS 498, 4192 (2020)

GOODS-ALMA: Using IRAC and VLA to probe fainter millimeter galaxies. Franco, M., Elbaz, D., Zhou, L., Magnelli, B., Schreiber, C., Ciesla, L., Dickinson, M., Nagar, N., Magdis, G., Alexander, D. M., Bethermin, M., Demarco, R., Daddi, E., Wang, T., Mullaney, J., Inami, H., Shu, X., Bournaud, F., Chary, R., Coogan, R. T., Ferguson, H., Finkelstein, S. L., Giavalisco, M., Gomez-Guijarro, C., Iono, D., Juneau, S., Lagache, G., Lin, L., Motohara, K., Okumura, K., Pannella, M., Papovich, C., Pope, A., Rujopakarn, W., Silverman, J., & Xiao, M. A&A 643, A53 (2020)

GOODS-ALMA: The slow downfall of star formation in z = 2-3 massive galaxies. Franco, M., Elbaz, D., Zhou, L., Magnelli, B., Schreiber, C., Ciesla, L., Dickinson, M., Nagar, N., Magdis, G., Alexander, D. M., Bethermin, M., Demarco, R., Daddi, E., Wang, T., Mullaney, J., Sargent, M., Inami, H., Shu, X., Bournaud, F., Chary, R., Coogan, R. T., Ferguson, H., Finkelstein, S. L., Giavalisco, M., Gomez-Guijarro, C., Iono, D., Juneau, S., Lagache, G., Lin, L., Motohara, K., Okumura, K., Pannella, M., Papovich, C., Pope, A., Rujopakarn, W., Silverman, J., & Xiao, M. A&A 643, A30 (2020)

The ALPINE-ALMA [CII] survey. Dust attenuation properties and obscured star formation at z ~ 4.4-5.8. Fudamoto, Y., Oesch, P. A., Faisst, A., Bethermin, M., Ginolfi, M., Khusanova, Y., Loiacono, F., Le Fevre, O., Capak, P., Schaerer, D., Silverman, J. D., Cassata, P., Yan, L., Amorin, R., Bardelli, S., Boquien, M., Cimatti, A., Dessauges-Zavadsky, M., Fujimoto, S., Gruppioni, C., Hathi, N. P., Ibar, E., Jones, G. C., Koekemoer, A. M., Lagache, G., Lemaux, B. C., Maiolino, R., Narayanan, D., Pozzi, F., Riechers, D. A., Rodighiero, G., Talia, M., Toft, S., Vallini, L., Vergani, D., Zamorani, G., & Zucca, E. A&A 643, A4 (2020)

A3COSMOS: the dust attenuation of star-forming galaxies at z = 2.5-4.0 from the COSMOS- ALMA archive. Fudamoto, Y., Oesch, P. A., Magnelli, B., Schinnerer, E., Liu, D., Lang, P., Jiminez- Andrade, E. F., Groves, B., Leslie, S., & Sargent, M. T. MNRAS 491, 4724 (2020)

Truth or Delusion? A Possible Gravitational Lensing Interpretation of the Ultraluminous Quasar SDSS J010013.02+280225.8 at z = 6.30. Fujimoto, S., Oguri, M., Nagao, T., Izumi, T., & Ouchi, M. ApJ 891, 64 (2020)

53

The ALPINE-ALMA [C II] Survey: Size of Individual Star-forming Galaxies at z = 4-6 and Their Extended Halo Structure. Fujimoto, S., Silverman, J. D., Bethermin, M., Ginolfi, M., Jones, G. C., Le Fevre, O., Dessauges-Zavadsky, M., Rujopakarn, W., Faisst, A. L., Fudamoto, Y., Cassata, P., Morselli, L., Maiolino, R., Schaerer, D., Capak, P., Yan, L., Vallini, L., Toft, S., Loiacono, F., Zamorani, G., Talia, M., Narayanan, D., Hathi, N. P., Lemaux, B. C., Boquien, M., Amorin, R., Ibar, E., Koekemoer, A. M., Mendez-Hernandez, H., Bardelli, S., Vergani, D., Zucca, E., Romano, M., & Cimatti, A. ApJ 900, 1 (2020)

Efficient Methanol Production on the Dark Side of a Prestellar Core. Harju, J., Pineda, J. E., Vasyunin, A. I., Caselli, P., Offner, S. S. R., Goodman, A. A., Juvela, M., Sipilä, O., Faure, A., Le Gal, R., Hily-Blant, P., Alves, J., Bizzocchi, L., Burkert, A., Chen, H., Friesen, R. K., Güsten, R., Myers, P. C., Punanova, A., Rist, C., Rosolowsky, E., Schlemmer, S., Shirley, Y., Spezzano, S., Vastel, C., & Wiesenfeld, L. ApJ 895, 101 (2020)

Megaparsec-scale structure around the protocluster core SPT2349-56 at z = 4.3. Hill, R., Chapman, S., Scott, D., Apostolovski, Y., Aravena, M., Bethermin, M., Bradford, C. M., Canning, R. E. A., De Breuck, C., Dong, C., Gonzalez, A., Greve, T. R., Hayward, C. C., Hezaveh, Y., Litke, K., Malkan, M., Marrone, D. P., Phadke, K., Reuter, C., Rotermund, K., Spilker, J., Vieira, J. D., & Weiß, A. MNRAS 495, 3124 (2020)

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP). I. Detection of New Hot Corinos with the ACA. Hsu, S.-Y., Liu, S.-Y., Liu, T., Sahu, D., Hirano, N., Lee, C.-F., Tatematsu, K., Kim, G., Juvela, M., Sanhueza, P., He, J., Johnstone, D., Qin, S.-L., Bronfman, L., Chen, H.-R. V., Dutta, S., Eden, D. J., Jhan, K.-S., Kim, K.-T., Kuan, Y.-J., Kwon, W., Lee, C. W., Lee, J.-E., Moraghan, A., Rawlings, M. G., Shang, H., Soam, A., Thompson, M. A., Traficante, A., Wu, Y., Yang, Y.-L., & Zhang, Q. ApJ 898, 107 (2020)

High Molecular Gas Masses in Absorption-selected Galaxies at z ≈ 2. Kanekar, N., Prochaska, J. X., Neeleman, M., Christensen, L., Møller, P., Zwaan, M. A., Fynbo, J. P. U., & Dessauges-Zavadsky, M. ApJ 901, L5 (2020)

ALMACAL VII: first interferometric number counts at 650 μm. Klitsch, A., Zwaan, M. A., Smail, I., Peroux, C., Biggs, A. D., Chen, C.-C., Ivison, R. J., Popping, G., Lagos, C., Bethermin, M., Swinbank, A. M., Hamanowicz, A., & Dutta, R. MNRAS 495, 2332 (2020)

ATOMS: ALMA three-millimeter observations of massive star-forming regions - II. Compact objects in ACA observations and star formation scaling relations. Liu, T., Evans, N. J., Kim, K.-T., Goldsmith, P. F., Liu, S.-Y., Zhang, Q., Tatematsu, K., Wang, K., Juvela, M., Bronfman, L., Cunningham, M. R., Garay, G., Hirota, T., Lee, J.-E., Kang, S.-J., Li, D., Li, P.-S., Mardones, D., Qin, S.-L., Ristorcelli, I., Tej, A., Toth, L. V., Wu, J.-W., Wu, Y.-F., Yi, H.-. weon ., Yun, H.-S., Liu, H.-L., Peng, Y.-P., Li, J., Li, S. H., Lee, C. W., Shen, Z.-Q., Baug, T., Wang, J.-Z., Zhang, Y., Issac, N., Zhu, F.-Y., Luo, Q.-Y.,

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Liu, X.-C., Xu, F.-W., Wang, Y., Zhang, C., Ren, Z., & Zhang, C. MNRAS 496, 2821 (2020)

ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - I. Survey description and a first look at G9.62+0.19. Liu, T., Evans, N. J., Kim, K.-T., Goldsmith, P. F., Liu, S.-Y., Zhang, Q., Tatematsu, K., Wang, K., Juvela, M., Bronfman, L., Cunningham, M. R., Garay, G., Hirota, T., Lee, J.-E., Kang, S.-J., Li, D., Li, P.-S., Mardones, D., Qin, S.-L., Ristorcelli, I., Tej, A., Toth, L. V., Wu, J.-W., Wu, Y.-F., Yi, H.-. weon ., Yun, H.-S., Liu, H.-L., Peng, Y.-P., Li, J., Li, S.-H., Lee, C. W., Shen, Z.-Q., Baug, T., Wang, J.-Z., Zhang, Y., Issac, N., Zhu, F.-Y., Luo, Q.-Y., Soam, A., Liu, X.-C., Xu, F.-W., Wang, Y., Zhang, C., Ren, Z., & Zhang, C. MNRAS 496, 2790 (2020)

The ALMA Spectroscopic Survey in the HUDF: The Cosmic Dust and Gas Mass Densities in Galaxies up to z ~ 3. Magnelli, B., Boogaard, L., Decarli, R., Gonzalez-Lopez, J., Novak, M., Popping, G., Smail, I., Walter, F., Aravena, M., Assef, R. J., Bauer, F. E., Bertoldi, F., Carilli, C., Cortes, P. C., Cunha, E. da ., Daddi, E., Diaz-Santos, T., Inami, H., Ivison, R. J., Fevre, O. L., Oesch, P., Riechers, D., Rix, H.-W., Sargent, M. T., Werf, P. van . der ., Wagg, J., Weiss, A. ApJ 892, 66 (2020)

ALMA Observations of Quasar Host Galaxies at z = 4.8. Nguyen, N. H., Lira, P., Trakhtenbrot, B., Netzer, H., Cicone, C., Maiolino, R., & Shemmer, O. ApJ 895, 74 (2020)

An ALMA Survey of H2CO in Protoplanetary Disks. Pegues, J., Öberg, K. I., Bergner, J. B., Loomis, R. A., Qi, C., Le Gal, R., Cleeves, L. I., Guzman, V. V., Huang, J., Jørgensen, J. K., Andrews, S. M., Blake, G. A., Carpenter, J. M., Schwarz, K. R., Williams, J. P., & Wilner, D. J. ApJ 890, 142 (2020)

Long Baseline Observations of the HD 100546 Protoplanetary Disk with ALMA. Perez, S., Casassus, S., Hales, A., Marino, S., Cheetham, A., Zurlo, A., Cieza, L., Dong, R., Alarcon, F., Benitez-Llambay, P., Fomalont, E., & Avenhaus, H. ApJ 889, L24 (2020)

The Complete Redshift Distribution of Dusty Star-forming Galaxies from the SPT-SZ Survey. Reuter, C., Vieira, J. D., Spilker, J. S., Weiss, A., Aravena, M., Archipley, M., Bethermin, M., Chapman, S. C., De Breuck, C., Dong, C., Everett, W. B., Fu, J., Greve, T. R., Hayward, C. C., Hill, R., Hezaveh, Y., Jarugula, S., Litke, K., Malkan, M., Marrone, D. P., Narayanan, D., Phadke, K. A., Stark, A. A., & Strandet, M. L. ApJ 902, 78 (2020)

Constraining the Chemical Signatures and the Outburst Mechanism of the Class 0 Protostar HOPS 383. Sharma, R., Tobin, J. J., Sheehan, P. D., Megeath, S. T., Fischer, W. J., Jørgensen, J. K., Safron, E. J., & Nagy, Z. ApJ 904, 78 (2020)

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Ubiquitous Molecular Outflows in z > 4 Massive, Dusty Galaxies. II. Momentum-driven Winds Powered by Star Formation in the Early Universe. Spilker, J. S., Aravena, M., Phadke, K. A., Bethermin, M., Chapman, S. C., Dong, C., Gonzalez, A. H., Hayward, C. C., Hezaveh, Y. D., Litke, K. C., Malkan, M. A., Marrone, D. P., Narayanan, D., Reuter, C., Vieira, J. D., & Weiß, A. ApJ 905, 86 (2020)

Ubiquitous Molecular Outflows in z > 4 Massive, Dusty Galaxies. I. Sample Overview and Clumpy Structure in Molecular Outflows on 500 pc Scales. Spilker, J. S., Phadke, K. A., Aravena, M., Bethermin, M., Chapman, S. C., Dong, C., Gonzalez, A. H., Hayward, C. C., Hezaveh, Y. D., Jarugula, S., Litke, K. C., Malkan, M. A., Marrone, D. P., Narayanan, D., Reuter, C., Vieira, J. D., & Weiss, A. ApJ 905, 85 (2020)

ALMA ACA and Nobeyama Observations of Two Orion Cores in Deuterated Molecular Lines. Tatematsu, K., Liu, T., Kim, G., Yi, H.-W., Lee, J.-E., Hirano, N., Liu, S.-Y., Ohashi, S., Sanhueza, P., Di Francesco, J., Evans, N. J., Fuller, G. A., Kandori, R., Choi, M., Kang, M., Feng, S., Hirota, T., Sakai, T., Lu, X., Lu'o'ng, Q. N., Thompson, M. A., Wu, Y., Li, D., Kim, K.-T., Wang, K., Ristorcelli, I., Juvela, M., & Toth, L. V. ApJ 895, 119 (2020)

The Molecular Gas in the NGC 6240 Merging Galaxy System at the Highest Spatial Resolution. Treister, E., Messias, H., Privon, G. C., Nagar, N., Medling, A. M., U, V., Bauer, F. E., Cicone, C., Munoz, L. B., Evans, A. S., Muller-Sanchez, F., Comerford, J. M., Armus, L., Chang, C.-S., Koss, M., Venturi, G., Schawinski, K., Casey, C., Urry, C. M., Sanders, D. B., Scoville, N., & Sheth, K. ApJ 890, 149 (2020)

CO emission in distant galaxies on and above the main sequence. Valentino, F., Daddi, E., Puglisi, A., Magdis, G. E., Liu, D., Kokorev, V., Cortzen, I., Madden, S., Aravena, M., Gomez-Guijarro, C., Lee, M.-Y., Le Floc'h, E., Gao, Y., Gobat, R., Bournaud, F., Dannerbauer, H., Jin, S., Dickinson, M. E., Kartaltepe, J., & Sanders, D. A&A 641, A155 (2020)

The Properties of the Interstellar Medium of Galaxies across Time as Traced by the Neutral Atomic Carbon [C I]. Valentino, F., Magdis, G. E., Daddi, E., Liu, D., Aravena, M., Bournaud, F., Cortzen, I., Gao, Y., Jin, S., Juneau, S., Kartaltepe, J. S., Kokorev, V., Lee, M.-Y., Madden, S. C., Narayanan, D., Popping, G., & Puglisi, A. ApJ 890, 24 (2020)

Temperature Structures of Embedded Disks: Young Disks in Taurus Are Warm. van't Hoff, M. L. R., Harsono, D., Tobin, J. J., Bosman, A. D., van Dishoeck, E. F., Jørgensen, J. K., Miotello, A., Murillo, N. M., & Walsh, C. ApJ 901, 166 (2020)

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The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space. Walter, F., Carilli, C., Neeleman, M., Decarli, R., Popping, G., Somerville, R. S., Aravena, M., Bertoldi, F., Boogaard, L., Cox, P., da Cunha, E., Magnelli, B., Obreschkow, D., Riechers, D., Rix, H.-W., Smail, I., Weiss, A., Assef, R. J., Bauer, F., Bouwens, R., Contini, T., Cortes, P. C., Daddi, E., Diaz-Santos, T., Gonzalez-Lopez, J., Hennawi, J., Hodge, J. A., Inami, H., Ivison, R., Oesch, P., Sargent, M., van der Werf, P., Wagg, J., & Yung, L. Y. A. ApJ 902, 111 (2020)

GOODS-ALMA: Optically dark ALMA galaxies shed light on a cluster in formation at z = 3.5. Zhou, L., Elbaz, D., Franco, M., Magnelli, B., Schreiber, C., Wang, T., Ciesla, L., Daddi, E., Dickinson, M., Nagar, N., Magdis, G., Alexander, D. M., Bethermin, M., Demarco, R., Mullaney, J., Bournaud, F., Ferguson, H., Finkelstein, S. L., Giavalisco, M., Inami, H., Iono, D., Juneau, S., Lagache, G., Messias, H., Motohara, K., Okumura, K., Pannella, M., Papovich, C., Pope, A., Rujopakarn, W., Shi, Y., Shu, X., & Silverman, J. A&A 642, A155 (2020)

APEX, publications in refereed journals 2020

Note: Based on APEX publications in the ESO Telescope Bibliography http://telbib.eso.org/.

Swedish authors (APEX)

Submillimetre water masers at 437, 439, 471, and 474 GHz towards evolved stars. APEX observations and radiative transfer modelling. Bergman, P., Humphreys, E. M. L. A&A 638, A19 (2020)

The surprisingly carbon-rich environment of the S-type star W Aql. De Beck, E., Olofsson, H. A&A 642, A20 (2020)

Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution. Kim, J.-Y., Krichbaum, T.P., Broderick, A.E., Wielgus, M., Blackburn, L., Gómez, J.L., Johnson, M.D., Bouman, K.L., Chael, A., Akiyama, K., Jorstad, S., Marscher, A.P., Issaoun, S., Janssen, M., Chan, C.-. kwan ., Savolainen, T., Pesce, D.W., Özel, F., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Ball, D., Baloković, M., Barrett, J., Bintley, D., Boland, W., Bower, G.C., Bremer, M., Brinkerink, C.D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D.-Y., Carlstrom, J.E., Chatterjee, S., Chatterjee, K., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J.E., Cordes, J.M., Crew, G.B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S.S., Eatough, R.P., Falcke, H., Fish, V.L., Fomalont, E., Fraga- Encinas, R., Friberg, P., Fromm, C.M., Galison, P., Gammie, C.F., García, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gómez-Ruiz, A.I., Gu, M., Gurwell, M., Hada, K., Hecht, M.H., Hesper, R., Ho, L.C., Ho, P., Honma, M., Huang, C.-W.L., Huang, L.,

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Hughes, D.H., Ikeda, S., Inoue, M., James, D.J., Jannuzi, B.T., Jeter, B., Jiang, W., Jimenez- Rosales, A., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G.K., Kettenis, M., Kim, J., Kim, J., Kino, M., Koay, J.Y., Koch, P.M., Koyama, S., Kramer, M., Kramer, C., Kuo, C.-Y., Lauer, T.R., Lee, S.-S., Li, Y.-R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W.-P., Lobanov, A.P., Loinard, L., Lonsdale, C., Lu, R.-S., MacDonald, N.R., Mao, J., Markoff, S., Marrone, D.P., Martí-Vidal, I., Matsushita, S., Matthews, L.D., Medeiros, L., Menten, K.M., Mizuno, Y., Mizuno, I., Moran, J.M., Moriyama, K., Moscibrodzka, M., Musoke, G., Müller, C., Nagai, H., Nagar, N.M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-León, G.N., Oyama, T., Palumbo, D.C.M., Park, J., Patel, N., Pen, U.-L., Piétu, V., Plambeck, R., PopStefanija, A., Porth, O., Prather, B., Preciado- López, J.A., Psaltis, D., Pu, H.-Y., Ramakrishnan, V., Rao, R., Rawlings, M.G., Raymond, A.W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A.L., Ruszczyk, C., Ryan, B.R., Rygl, K.L.J., Sánchez, S., Sánchez-Arguelles, D., Sasada, M., Schloerb, F.P., Schuster, K.-F., Shao, L., Shen, Z., Small, D., Sohn, B.W., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R.P.J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., van Bemmel, I., van Langevelde, H.J., van Rossum, D.R., Wagner, J., Wardle, J., Ward-Thompson, D., Weintroub, J., Wex, N., Wharton, R., Wong, G.N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y.-F., Zensus, J.A., Zhao, G., Zhao, S.-S., Zhu, Z., Algaba, J.-C., Allardi, A., Amestica, R., Anczarski, J., Bach, U., Baganoff, F.K., Beaudoin, C., Benson, B.A., Berthold, R., Blanchard, J.M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Domínguez, E., Chang, C.-C., Chang, S.-H., Chang, S.-C., Chen, C.-C., Chilson, R., Chuter, T.C., Rosado, R.C., Coulson, I.M., Crowley, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K.A., Dzib, S.A., Eckart, A., Eckert, C., Erickson, N.R., Everett, W.B., Faber, A., Farah, J.R., Fath, V., Folkers, T.W., Forbes, D.C., Freund, R., Gale, D.M., Gao, F., Geertsema, G., Graham, D.A., Greer, C.H., Grosslein, R., Gueth, F., Haggard, D., Halverson, N.W., Han, C.-C., Han, K.-C., Hao, J., Hasegawa, Y., Henning, J.W., Hernández-Gómez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y.-D., Violette Impellizzeri, C.M., Jiang, H., John, D., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R.A., Leitch, E.M., Li, C.-T., Lin, L.C.-C., Liu, C.-T., Liu, K.-Y., Lu, L.-M., Marson, R.G., Martin-Cocher, P.L., Massingill, K.D., Matulonis, C., McColl, M.P., McWhirter, S.R., Messias, H., Meyer- Zhao, Z., Michalik, D., Montaña, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Neilsen, J., Nguyen, C.H., Nishioka, H., Norton, T., Nowak, M.A., Nystrom, G., Ogawa, H., Oshiro, P., Oyama, T., Parsons, H., Peñalver, J., Phillips, N.M., Poirier, M., Pradel, N., Primiani, R.A., Raffin, P.A., Rahlin, A.S., Reiland, G., Risacher, C., Ruiz, I., Sáez-Madaín, A.F., Sassella, R., Schellart, P., Shaw, P., Silva, K.M., Shiokawa, H., Smith, D.R., Snow, W., Souccar, K., Sousa, D., Sridharan, T.K., Srinivasan, R., Stahm, W., Stark, A.A., Story, K., Timmer, S.T., Vertatschitsch, L., Walther, C., Wei, T.-S., Whitehorn, N., Whitney, A.R., Woody, D.P., Wouterloot, J.G.A., Wright, M., Yamaguchi, P., Yu, C.-Y., Zeballos, M., Zhang, S., Ziurys, L., and Event Horizon Telescope Collaboration. A&A 640, A69 (2020)

The Lyman Alpha Reference Sample. XI. Efficient turbulence-driven Lyα escape and an analysis of IR, CO, and [C II]158 μm. Puschnig, J., Hayes, M., Östlin, G., Cannon, J., Smirnova-Pinchukova, I., Husemann, B., Kunth, D., Bridge, J., Herenz, E. C., Messa, M., Oteo, I. A&A 644, A10 (2020)

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Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope. Wielgus, M., Akiyama, K., Blackburn, L., Chan, C.-. kwan ., Dexter, J., Doeleman, S.S., Fish, V.L., Issaoun, S., Johnson, M.D., Krichbaum, T.P., Lu, R.-S., Pesce, D.W., Wong, G.N., Bower, G.C., Broderick, A.E., Chael, A., Chatterjee, K., Gammie, C.F., Georgiev, B., Hada, K., Loinard, L., Markoff, S., Marrone, D.P., Plambeck, R., Weintroub, J., Dexter, M., MacMahon, D.H.E., Wright, M., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Ball, D., Baloković, M., Barausse, E., Barrett, J., Bintley, D., Boland, W., Bouman, K.L., Bremer, M., Brinkerink, C.D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D.-Y., Carlstrom, J.E., Chatterjee, S., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J.E., Cordes, J.M., Crew, G.B., Cui, Y., Davelaar, J., Laurentis, M.D., Deane, R., Dempsey, J., Desvignes, G., Dzib, S.A., Eatough, R.P., Falcke, H., Fomalont, E., Fraga- Encinas, R., Friberg, P., Fromm, C.M., Galison, P., García, R., Gentaz, O., Goddi, C., Gold, R., Gómez, J.L., Gómez-Ruiz, A.I., Gu, M., Gurwell, M., Hecht, M.H., Hesper, R., Ho, L.C., Ho, P., Honma, M., Huang, C.-W.L., Huang, L., Hughes, D.H., Inoue, M., James, D.J., Jannuzi, B.T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G.K., Kettenis, M., Kim, J.-Y., Kim, J., Kim, J., Kino, M., Koay, J.Y., Koch, P.M., Koyama, S., Kramer, M., Kramer, C., Kuo, C.-Y., Lauer, T.R., Lee, S.-S., Li, Y.-R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W.-P., Lobanov, A.P., Lonsdale, C., MacDonald, N.R., Mao, J., Marchili, N., Marscher, A.P., Martí-Vidal, I., Matsushita, S., Matthews, L.D., Medeiros, L., Menten, K.M., Mizuno, Y., Mizuno, I., Moran, J.M., Moriyama, K., Moscibrodzka, M., Müller, C., Musoke, G., Nagai, H., Nagar, N.M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz- León, G.N., Oyama, T., Özel, F., Palumbo, D.C.M., Park, J., Patel, N., Pen, U.-L., Piétu, V., PopStefanija, A., Porth, O., Prather, B., Preciado-López, J.A., Psaltis, D., Pu, H.-Y., Ramakrishnan, V., Rao, R., Rawlings, M.G., Raymond, A.W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A.L., Ruszczyk, C., Ryan, B.R., Rygl, K.L.J., Sánchez, S., Sánchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F.P., Schuster, K.-F., Shao, L., Shen, Z., Small, D., Sohn, B.W., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R.P.J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., Bemmel, I. van ., van Langevelde, H.J., van Rossum, D.R., Wagner, J., Wardle, J., Ward-Thompson, D., Wex, N., Wharton, R., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y.-F., Zensus, J.A., Zhao, G., Zhao, S.-S., and Zhu, Z. ApJ 901, 67 (2020)

International authors (APEX)

Unusual Galactic H II Regions at the Intersection of the Central Molecular Zone and the Far Dust Lane. Anderson, L. D., Sormani, M. C., Ginsburg, Adam, Glover, Simon C. O., Heywood, I., Rammala, I., Schuller, F., Csengeri, T., Urquhart, J. S., Bronfman, Leonardo. ApJ 901, 51 (2020)

Deuterium fractionation of nitrogen hydrides: detections of NHD and ND2. Bacmann, A., Faure, A., Hily-Blant, P., Kobayashi, K., Ozeki, H., Yamamoto, S., Pagani, L., Lique, F. MNRAS 499, 1795 (2020)

59

CMZoom: Survey Overview and First Data Release. Battersby, C., Keto, E., Walker, D., Barnes, A., Callanan, D., Ginsburg, A., Hatchfield, H.P., Henshaw, J., Kauffmann, J., Kruijssen, J.M.D., Longmore, S.N., Lu, X., Mills, E.A.C., Pillai, T., Zhang, Q., Bally, J., Butterfield, N., Contreras, Y.A., Ho, L.C., Ott, J., Patel, N., and Tolls, V. ApJS 249, 35 (2020)

ALMA Observations Reveal No Preferred Outflow-filament and Outflow-magnetic Field Orientations in Protoclusters. Baug, T., Wang, Ke, Liu, Tie, Tang, Mengyao, Zhang, Qizhou, Li, Di, Eswaraiah, Chakali, Liu, Sheng-Yuan, Tej, Anandmayee, Goldsmith, Paul F., Bronfman, Leonardo, Qin, Sheng- Li, Tóth, Viktor L., Li, Pak-Shing, Kim, Kee-Tae. ApJ 890, 44 (2020)

The multi-phase ISM in the nearby composite AGN-SB galaxy NGC 4945: large-scale () mechanical heating. Bellocchi, E., Martín-Pintado, J., Güsten, R., Requena-Torres, M. A., Harris, A., van der Werf, P. P., Israel, F. P., Weiss, A., Kramer, C., García-Burillo, S., Stutzki, J. A&A 642, A166 (2020)

Dynamical cloud formation traced by atomic and molecular gas. Beuther, H., Wang, Y., Soler, J., Linz, H., Henshaw, J., Vazquez-Semadeni, E., Gomez, G., Ragan, S., Henning, Th., Glover, S. C. O., Lee, M. -Y., Güsten, R. A&A 638, A44 (2020)

ATLASGAL - relationship between dense star-forming clumps and interstellar masers. Billington, S. J., Urquhart, J. S., König, C., Beuther, H., Breen, S. L., Menten, K. M., Campbell-White, J., Ellingsen, S. P., Thompson, M. A., Moore, T. J. T., Eden, D. J., Kim, W.-J., Leurini, S. MNRAS 499, 2744 (2020)

Formation of the filament: evidence for asymmetries in the accretion flow due to a cloud-cloud collision. Bonne, L., Bontemps, S., Schneider, N., Clarke, S. D., Arzoumanian, D., Fukui, Y., Tachihara, K., Csengeri, T., Guesten, R., Ohama, A., Okamoto, R., Simon, R., Yahia, H., Yamamoto, H. A&A 644, A27 (2020)

Dense gas formation in the Musca filament due to the dissipation of a supersonic converging flow. Bonne, L., Schneider, N., Bontemps, S., Clarke, S. D., Gusdorf, A., Lehmann, A., Steinke, M., Csengeri, T., Kabanovic, S., Simon, R., Buchbender, C., Güsten, R. A&A 641, A17 (2020)

An imaging line survey of OMC-1 to OMC-3. Averaged spectra of template regions. Brinkmann, N., Wyrowski, F., Kauffmann, J., Colombo, D., Menten, K. M., Tang, X. D., Güsten, R. A&A 636, A39 (2020)

60

The EDGE-CALIFA survey: exploring the role of molecular gas on galaxy star formation quenching. Colombo, D., Sanchez, S. F., Bolatto, A. D., Kalinova, V., Weiß, A., Wong, T., Rosolowsky, E., Vogel, S. N., Barrera-Ballesteros, J., Dannerbauer, H., Cao, Y., Levy, R. C., Utomo, D., Blitz, L. A&A 644, A97 (2020)

An ALMA view of SO and SO2 around oxygen-rich AGB stars. Danilovich, T., Richards, A. M. S., Decin, L., Van de Sande, M., Gottlieb, C. A. MNRAS 494, 1323 (2020)

GASP XXV: neutral hydrogen gas in the striking jellyfish galaxy JO204. Deb, T., Verheijen, M.A.W., Gullieuszik, M., Poggianti, B.M., van Gorkom, J.H., Ramatsoku, M., Serra, P., Moretti, A., Vulcani, B., Bettoni, D., Jaffé, L.Y., Tonnesen, S., and Fritz, J. MNRAS 494, 5029 (2020)

Interstellar anatomy of the TeV gamma-ray peak in the IC443 supernova remnant. Dell'Ova, P., Gusdorf, A., Gerin, M., Riquelme, D., Güsten, R., Noriega-Crespo, A., Tram, L.N., Houde, M., Guillard, P., Lehmann, A., Lesaffre, P., Louvet, F., Marcowith, A., Padovani, M. A&A 644, A64 (2020)

Uncovering distinct environments in an extended physical system around the W33 complex. Dewangan, L. K., Baug, T., Ojha, D. K. MNRAS 496, 1278 (2020)

Investigating the Physical Conditions in Extended System Hosting Mid-infrared Bubble N14. Dewangan, L. K., Baug, T., Pirogov, L. E., Ojha, D. K. ApJ 898, 41 (2020)

Betelgeuse Fainter in the Submillimeter Too: An Analysis of JCMT and APEX Monitoring during the Recent Optical Minimum. Dharmawardena, T.E., Mairs, S., Scicluna, P., Bell, G., McDonald, I., Menten, K., Weiss, A., and Zijlstra, A. ApJL 897, L9 (2020)

The Chemical Structure of Young High-mass Star-forming Clumps. II. -scale CO Depletion and Deuterium Fraction of HCO+. Feng, S., Li, D., Caselli, P., Du, F., Lin, Y., Sipilä, O., Beuther, H., Sanhueza, Patricio, Tatematsu, K., Liu, S. Y., Zhang, Q., Wang, Y., Hogge, T., Jimenez-Serra, I., Lu, X., Liu, T., Wang, K., Zhang, Z. Y., Zahorecz, S., Li, G., Liu, H. B., Yuan, J. ApJ 901, 145 (2020)

Multifrequency study of HH 137 and HH 138: discovering new knots and molecular outflows with Gemini and APEX. Ferrero, L.V., Cappa, C.E., Saldaño, H.P., Gómez, M., Rubio, M., and Günthardt, G. MNRAS 496, 4239 (2020)

61

APEX CO observations towards the photodissociation region of RCW 120. Figueira, M., Zavagno, A., Bronfman, L., Russeil, D., Finger, R., Schuller, F. A&A 639, A93 (2020)

Simulating the circumstellar H2CO and CH3OH chemistry of young stellar objects using a spherical physical-chemical model. Fuchs, G. W., Witsch, D., Herberth, D., Kempkes, M., Stanclik, B., Chantzos, J., Linnartz, H., Menten, K. M., Giesen, T. F. A&A 639, A143 (2020)

Deep search for hydrogen peroxide toward pre- and protostellar objects. Testing the pathway of grain surface water formation. Fuchs, G. W., Witsch, D., Herberth, D., Kempkes, M., Stanclik, B., Chantzos, J., Linnartz, H., Menten, K., Giesen, T. F. A&A 636, A114 (2020)

DeGaS-MC: Dense Gas Survey in the Magellanic Clouds. I. An APEX survey of HCO+ and HCN(2-1) toward the LMC and SMC. Galametz, M., Schruba, A., De Breuck, C., Immer, K., Chevance, M., Galliano, F., Gusdorf, A., Lebouteiller, V., Lee, M. Y., Madden, S. C., Polles, F. L., van Kempen, T. A. A&A 643, A63 (2020)

The Clustering of Submillimeter Galaxies Detected with ALMA. García-Vergara, C., Hodge, J., Hennawi, J.F., Weiss, A., Wardlow, J., Myers, A.D., Hickox, R. ApJ 904, 2 (2020)

The MUSTANG Galactic Plane Survey (MGPS90) Pilot. Ginsburg, A., Anderson, L.D., Dicker, S., Romero, C., Svoboda, B., Devlin, M., Galván- Madrid, R., Indebetouw, R., Liu, H.B., Mason, B., Mroczkowski, T., Armentrout, W.P., Bally, J., Brogan, C., Butterfield, N., Hunter, T.R., Reese, E.D., Rosolowsky, E., Sarazin, C., Shirley, Y., Sievers, J., and Stanchfield, S. ApJS 248, 24 (2020)

APEX-SEPIA660 Early Science: gas at densities above 107 cm−3 towards OMC-1. Hacar, A., Hogerheijde, M. R., Harsono, D., Portegies Zwart, S., De Breuck, C., Torstensson, K., Boland, W., Baryshev, A. M., Hesper, R., Barkhof, J., Adema, J., Bekema, M. E., Koops, A., Khudchenko, A., Stark, R. A&A 644, A133 (2020)

Megaparsec-scale structure around the protocluster core SPT2349-56 at z = 4.3. Hill, R., Chapman, S., Scott, D., Apostolovski, Y., Aravena, M., Béthermin, M., Bradford, C.M., Canning, R.E.A., De Breuck, C., Dong, C., Gonzalez, A., Greve, T.R., Hayward, C.C., Hezaveh, Y., Litke, K., Malkan, M., Marrone, D.P., Phadke, K., Reuter, C., Rotermund, K., Spilker, J., Vieira, J.D., and Weiß, A. MNRAS 495, 3124 (2020)

62

Sulphur and carbon isotopes towards Galactic centre clouds. Humire, P. K., Thiel, V., Henkel, C., Belloche, A., Loison, J. -C., Pillai, T., Riquelme, D., Wakelam, V., Langer, N., Hernández-Gómez, A., Mauersberger, R., Menten, K. M. A&A 642, A222 (2020)

Structural and Dynamical Analysis of 0.1 pc Cores and Filaments in the 30 Doradus-10 Giant Molecular Cloud. Indebetouw, R., Wong, T., Chen, C.-H.R., Kepley, A., Lebouteiller, V., Madden, S., and Oliveira, J.M. ApJ 888, 56 (2020)

Multiwavelength investigation of extended green object G19.88-0.53: revealing a protocluster. Issac, N., Tej, A., Liu, T., Varricatt, W., Vig, S., Ishwara Chandra, C.H., Schultheis, M., and Nandakumar, G. MNRAS 497, 5454 (2020)

Extending the view of ArH+ chemistry in diffuse clouds. Jacob, A.M., Menten, K.M., Wyrowski, F., Winkel, B., and Neufeld, D.A. A&A 643, A91 (2020)

High molecular gas content and star formation rates in local galaxies that host quasars, outflows, and jets. Jarvis, M. E., Harrison, C. M., Mainieri, V., Calistro Rivera, G., Jethwa, P., Zhang, Z. -Y., Alexander, D. M., Circosta, C., Costa, T., De Breuck, C., Kakkad, D., Kharb, P., Lansbury, G.B., Thomson, A. P. MNRAS 498, 1560 (2020)

A Detailed View of the Circumstellar Environment and Disk of the Forming O-star AFGL 4176. Johnston, K.G., Hoare, M.G., Beuther, H., Linz, H., Boley, P., Kuiper, R., Kee, N.D., and Robitaille, T.P. ApJ 896, 35 (2020)

ATLASGAL-selected massive clumps in the inner Galaxy. VIII. Chemistry of photodissociation regions. Kim, W. -J., Wyrowski, F., Urquhart, J. S., Pérez-Beaupuits, J. P., Pillai, T., Tiwari, M., Menten, K. M. A&A 644, A160 (2020)

The Physical Parameters of Clumps Associated with Class I Methanol Masers. Ladeyschikov, D.A., Urquhart, J.S., Sobolev, A.M., Breen, S.L., and Bayandina, O.S. AJ 160, 213 (2020)

A Mean Density of 112 M☉ pc-3 for Central Molecular Zone Clumps—Evidences for Shear- enabled Pressure Equilibrium in the Galactic Center. Li, G.-X. and Zhang, C.-P. ApJ 897, 89 (2020)

63

ALMA Observations of NGC 6334S. I. Forming Massive Stars and Clusters in Subsonic and Transonic Filamentary Clouds. Li, S., Zhang, Q., Liu, H.B., Beuther, H., Palau, A., Girart, J.M., Smith, H., Hora, J.L., Lin, Y., Qiu, K., Strom, S., Wang, J., Li, F., Yue, N. ApJ 896, 110 (2020)

Chemistry of Protostellar Clumps in the High-mass, Star-forming Filamentary Infrared Dark Cloud G034.43+00.24. Liu, H.-L., Sanhueza, P., Liu, T., Zavagno, A., Tang, X.-D., Wu, Y., and Zhang, S. ApJ 901, 31 (2020)

Discovery of a mid-infrared protostellar outburst of exceptional amplitude. Lucas, P. W., Elias, J., Points, S., Guo, Z., Smith, L. C., Stecklum, B., Vorobyov, E., Morris, C., Borissova, J., Kurtev, R., Contreras Peña, C., Medina, N., Minniti, D., Ivanov, V.D., Saito, R. K. MNRAS 499, 1805 (2020)

What did the seahorse swallow? APEX 170 GHz observations of the chemical conditions in the Seahorse infrared dark cloud. Miettinen, O. A&A 639, A65 (2020)

Dense cores in the Seahorse infrared dark cloud: physical properties from modified blackbody fits to the far-infrared-submillimetre spectral energy distributions. Miettinen, O. A&A 644, A82 (2020)

APEX observations of ortho-H2D+ towards dense cores in the Orion B9 filament. Miettinen, O. A&A 634, A115 (2020)

An APEX survey of outflow and infall toward the youngest protostars in Orion. Nagy, Z., Menechella, A., Megeath, S. T., Tobin, J. J., Booker, J. J., Fischer, W. J., Manoj, P., Stanke, T., Stutz, A., Wyrowski, F. A&A 642, A137 (2020)

Cosmic evolution of molecular gas mass density from an empirical relationship between ' L1.4 GHz and L CO. Orellana-González, G., Ibar, E., Leiton, R., Thomson, A. P., Cheng, C., Ivison, R. J., Herrera- Camus, R., Messias, H., Calderón-Castillo, P., Hughes, T. M., Leeuw, L. MNRAS 495, 1760 (2020)

Probing the early phases of high-mass star formation with 6.7 GHz methanol masers. Paulson, S.T., Pandian, J.D. MNRAS 492, 1335 (2020)

64

The accretion history of high-mass stars: an ArTéMiS pilot study of infrared dark clouds. Peretto, N., Rigby, A., André, Ph, Könyves, V., Fuller, G., Zavagno, A., Schuller, F., Arzoumanian, D., Bontemps, S., Csengeri, T., Didelon, P., Duarte-Cabral, A., Palmeirim, P., Pezzuto, S., Revéret, V., Roussel, H., Shimajiri, Y. MNRAS 496, 3482 (2020)

Linking ice and gas in the Serpens low-mass star-forming region. Perotti, G., Rocha, W. R. M., Jørgensen, J. K., Kristensen, L. E., Fraser, H. J., Pontoppidan, K. M. A&A 643, A48 (2020)

Effect of Feedback of Massive Stars in the Fragmentation, Distribution, and Kinematics of the Gas in Two Star-forming Regions in the Carina Nebula. Rebolledo, D., Guzmán, A.E., Contreras, Y., Garay, G., Medina, S.-N.X., Sanhueza, P., Green, A.J., Castro, C., Guzmán, V., and Burton, M.G. ApJ 891, 113 (2020)

Illuminating a tadpole's metamorphosis II: observing the ongoing transformation with ALMA. Reiter, M., Guzmán, A.E., Haworth, T.J., Klaassen, P.D., McLeod, A.F., Garay, G., and Mottram, J.C. MNRAS 496, 394 (2020)

The Complete Redshift Distribution of Dusty Star-forming Galaxies from the SPT-SZ Survey. Reuter, C., Vieira, J. D., Spilker, J. S., Weiss, A., Aravena, M., Archipley, M., Béthermin, M., Chapman, S. C., De Breuck, C., Dong, C., Everett, W. B., Fu, J., Greve, T. R., Hayward, C.C., Hill, R., Hezaveh, Y., Jarugula, S., Litke, K., Malkan, M., Marrone, D. P., Narayanan, D., Phadke, K. A., Stark, A. A., Strandet, M. L. ApJ 902, 78 (2020)

First Detection of the [O i] 63 μm Emission from a Redshift 6 Dusty Galaxy. Rybak, M., Zavala, J.A., Hodge, J.A., Casey, C.M., and Werf, P. van . der . ApJL 889, L11 (2020)

Survey of ortho-H2D+ in high-mass star-forming regions. Sabatini, G., Bovino, S., Giannetti, A., Wyrowski, F., Órdenes, M. A., Pascale, R., Pillai, T., Wienen, M., Csengeri, T., Menten, K. M. A&A 644, A34 (2020)

Molecular gas in the central region of NGC 7213. Salvestrini, F., Gruppioni, C., Pozzi, F., Vignali, C., Giannetti, A., Paladino, R., Hatziminaoglou, E. A&A 641, A151 (2020)

The Molecular Outflow from R Mon. Sandell, G., Vacca, W., Bouscasse, L., and Güsten, R. ApJ 889, 138 (2020)

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FEEDBACK: a SOFIA Legacy Program to Study Stellar Feedback in Regions of Massive Star Formation. Schneider, N., Simon, R., Guevara, C., Buchbender, C., Higgins, R. D., Okada, Y., Stutzki, J., Güsten, R., Anderson, L. D., Bally, J., Beuther, H., Bonne, L., Bontemps, S., Chambers, E., Csengeri, T., Graf, U. U., Gusdorf, A., Jacobs, K., Justen, M., Kabanovic, S., Karim, R., Luisi, M., Menten, K., Mertens, M., Mookerjea, B., Ossenkopf-Okada, V., Pabst, C., Pound, M. W., Richter, H., Reyes, N., Ricken, O., Röllig, M., Russeil, D., Sánchez- Monge, Á., Sandell, G., Tiwari, M., Wiesemeyer, H., Wolfire, M., Wyrowski, F., Zavagno, A., Tielens, A.G.G.M. PASP 132, 104301 (2020)

Oversized Gas Clumps in an Extremely Metal-poor Molecular Cloud Revealed by ALMA's Parsec-scale Maps. Shi, Y., Wang, J., Zhang, Z.-Y., Zhang, Q., Gao, Y., Zhou, L., Gu, Q., Qiu, K., Xia, X.-Y., Hao, C.-N., and Chen, Y. ApJ 892, 147 (2020)

Cause and effects of the massive star formation in Messier 8 East. Tiwari, M., Menten, K. M., Wyrowski, F., Giannetti, A., Lee, M. -Y., Kim, W. -J., Pérez- Beaupuits, J. P. A&A 644, A25 (2020)

ALMA resolves molecular clouds in metal-poor Magellanic Bridge A. Valdivia-Mena, M. T., Rubio, M., Bolatto, A. D., Saldaño, H. P., Verdugo, C. A&A 641, A97 (2020)

AlFoCS + Fornax3D: resolved star formation in the Fornax cluster with ALMA and MUSE. Zabel, N., Davis, T. A., Sarzi, M., Nedelchev, Boris, Chevance, M., Kruijssen, J. M. Diederik, Iodice, E., Baes, M., Bendo, G. J., Corsini, E. Maria, De Looze, I., de Zeeuw, P. Tim, Gadotti, D. A., Grossi, M., Peletier, R., Pinna, F., Serra, Paolo, van de Voort, F., Venhola, A., Viaene, S., Vlahakis, C. MNRAS 496, 2155 (2020)

The role of Galactic H II regions in the formation of filaments. High-resolution submilimeter imaging of RCW 120 with ArTéMiS. Zavagno, A., André, Ph., Schuller, F., Peretto, N., Shimajiri, Y., Arzoumanian, D., Csengeri, T., Figueira, M., Fuller, G. A., Könyves, V., Men'shchikov, A., Palmeirim, P., Roussel, H., Russeil, D., Schneider, N., Zhang, S. A&A 638, A7 (2020)

Cloud-cloud collision as drivers of the chemical complexity in Galactic Centre molecular clouds. Zeng, S., Zhang, Q., Jiménez-Serra, I., Tercero, B., Lu, X., Martín-Pintado, J., de Vicente, P., Rivilla, V. M., Li, S. MNRAS 497, 4896 (2020)

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H II regions and high-mass starless clump candidates. I. Catalogs and properties. Zhang, S., Zavagno, A., Yuan, J., Liu, H., Figueira, M., Russeil, D., Schuller, F., Marsh, K.A., Wu, Y. A&A 637, A40 (2020)

Astronomical VLBI, publications in refereed journals 2020

Swedish authors (Astro VLBI)

The case against gravitational millilensing in the multiply-imaged quasar B1152+199. Asadi, S., Zackrisson, E., Varenius, E., Freeland, E., Conway, J., and Wiik, K. MNRAS 492, 742 (2020)

Periodic activity from a fast radio burst source. Chime/Frb Collaboration, Amiri, M., Andersen, B.C., Bandura, K.M., Bhardwaj, M., Boyle, P.J., Brar, C., Chawla, P., Chen, T., Cliche, J.F., Cubranic, D., Deng, M., Denman, N.T., Dobbs, M., Dong, F.Q., Fandino, M., Fonseca, E., Gaensler, B.M., Giri, U., Good, D.C., Halpern, M., Hessels, J.W.T., Hill, A.S., Höfer, C., Josephy, A., Kania, J.W., Karuppusamy, R., Kaspi, V.M., Keimpema, A., Kirsten, F., Landecker, T.L., Lang, D.A., Leung, C., Li, D.Z., Lin, H.-H., Marcote, B., Masui, K.W., McKinven, R., Mena-Parra, J., Merryfield, M., Michilli, D., Milutinovic, N., Mirhosseini, A., Naidu, A., Newburgh, L.B., Ng, C., Nimmo, K., Paragi, Z., Patel, C., Pen, U.-L., Pinsonneault-Marotte, T., Pleunis, Z., Rafiei-Ravandi, M., Rahman, M., Ransom, S.M., Renard, A., Sanghavi, P., Scholz, P., Shaw, J.R., Shin, K., Siegel, S.R., Singh, S., Smegal, R.J., Smith, K.M., Stairs, I.H., Tendulkar, S.P., Tretyakov, I., Vanderlinde, K., Wang, H., Wang, X., Wulf, D., Yadav, P., and Zwaniga, A.V. Nature 582, 351 (2020)

The Hyperluminous, Dust-obscured Quasar W2246-0526 at z = 4.6: Detection of Parsec- scale Radio Activity. Fan, L., Chen, W., An, T., Xie, F.-G., Han, Y., Knudsen, K.K., and Yang, J. ApJ 905, L32 (2020)

Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution. Kim, J.-Y., Krichbaum, T.P., Broderick, A.E., Wielgus, M., Blackburn, L., Gómez, J.L., Johnson, M.D., Bouman, K.L., Chael, A., Akiyama, K., Jorstad, S., Marscher, A.P., Issaoun, S., Janssen, M., Chan, C.-. kwan ., Savolainen, T., Pesce, D.W., Özel, F., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A.-K., Ball, D., Baloković, M., Barrett, J., Bintley, D., Boland, W., Bower, G.C., Bremer, M., Brinkerink, C.D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D.-Y., Carlstrom, J.E., Chatterjee, S., Chatterjee, K., Chen, M.-T., Chen, Y., Cho, I., Christian, P., Conway, J.E., Cordes, J.M., Crew, G.B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S.S., Eatough, R.P., Falcke, H., Fish, V.L., Fomalont, E., Fraga- Encinas, R., Friberg, P., Fromm, C.M., Galison, P., Gammie, C.F., García, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gómez-Ruiz, A.I., Gu, M., Gurwell, M., Hada, K., Hecht, M.H., Hesper, R., Ho, L.C., Ho, P., Honma, M., Huang, C.-W.L., Huang, L., Hughes, D.H., Ikeda, S., Inoue, M., James, D.J., Jannuzi, B.T., Jeter, B., Jiang, W., Jimenez-

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Rosales, A., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G.K., Kettenis, M., Kim, J., Kim, J., Kino, M., Koay, J.Y., Koch, P.M., Koyama, S., Kramer, M., Kramer, C., Kuo, C.-Y., Lauer, T.R., Lee, S.-S., Li, Y.R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W.-P., Lobanov, A.P., Loinard, L., Lonsdale, C., Lu, R.-S., MacDonald, N.R., Mao, J., Markoff, S., Marrone, D.P., Martí-Vidal, I., Matsushita, S., Matthews, L.D., Medeiros, L., Menten, K.M., Mizuno, Y., Mizuno, I., Moran, J.M., Moriyama, K., Moscibrodzka, M., Musoke, G., Müller, C., Nagai, H., Nagar, N.M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-León, G.N., Oyama, T., Palumbo, D.C.M., Park, J., Patel, N., Pen, U.-L., Piétu, V., Plambeck, R., PopStefanija, A., Porth, O., Prather, B., Preciado- López, J.A., Psaltis, D., Pu, H.-Y., Ramakrishnan, V., Rao, R., Rawlings, M.G., Raymond, A.W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A.L., Ruszczyk, C., Ryan, B.R., Rygl, K.L.J., Sánchez, S., Sánchez-Arguelles, D., Sasada, M., Schloerb, F.P., Schuster, K.-F., Shao, L., Shen, Z., Small, D., Sohn, B.W., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R.P.J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., van Bemmel, I., van Langevelde, H.J., van Rossum, D.R., Wagner, J., Wardle, J., Ward-Thompson, D., Weintroub, J., Wex, N., Wharton, R., Wong, G.N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y.-F., Zensus, J.A., Zhao, G., Zhao, S.-S., Zhu, Z., Algaba, J.-C., Allardi, A., Amestica, R., Anczarski, J., Bach, U., Baganoff, F.K., Beaudoin, C., Benson, B.A., Berthold, R., Blanchard, J.M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Domínguez, E., Chang, C.-C., Chang, S.-H., Chang, S.-C., Chen, C.-C., Chilson, R., Chuter, T.C., Rosado, R.C., Coulson, I.M., Crowley, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K.A., Dzib, S.A., Eckart, A., Eckert, C., Erickson, N.R., Everett, W.B., Faber, A., Farah, J.R., Fath, V., Folkers, T.W., Forbes, D.C., Freund, R., Gale, D.M., Gao, F., Geertsema, G., Graham, D.A., Greer, C.H., Grosslein, R., Gueth, F., Haggard, D., Halverson, N.W., Han, C.-C., Han, K.-C., Hao, J., Hasegawa, Y., Henning, J.W., Hernández-Gómez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y.-D., Violette Impellizzeri, C.M., Jiang, H., John, D., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R.A., Leitch, E.M., Li, C.-T., Lin, L.C.-C., Liu, C.-T., Liu, K.-Y., Lu, L.-M., Marson, R.G., Martin-Cocher, P.L., Massingill, K.D., Matulonis, C., McColl, M.P., McWhirter, S.R., Messias, H., Meyer- Zhao, Z., Michalik, D., Montaña, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Neilsen, J., Nguyen, C.H., Nishioka, H., Norton, T., Nowak, M.A., Nystrom, G., Ogawa, H., Oshiro, P., Oyama, T., Parsons, H., Peñalver, J., Phillips, N.M., Poirier, M., Pradel, N., Primiani, R.A., Raffin, P.A., Rahlin, A.S., Reiland, G., Risacher, C., Ruiz, I., Sáez-Madaín, A.F., Sassella, R., Schellart, P., Shaw, P., Silva, K.M., Shiokawa, H., Smith, D.R., Snow, W., Souccar, K., Sousa, D., Sridharan, T.K., Srinivasan, R., Stahm, W., Stark, A.A., Story, K., Timmer, S.T., Vertatschitsch, L., Walther, C., Wei, T.-S., Whitehorn, N., Whitney, A.R., Woody, D.P., Wouterloot, J.G.A., Wright, M., Yamaguchi, P., Yu, C.-Y., Zeballos, M., Zhang, S., Ziurys, L., and Event Horizon Telescope Collaboration. A&A 640, A69 (2020)

Detection of two bright radio bursts from magnetar SGR 1935 + 2154. Kirsten, F., Snelders, M.P., Jenkins, M., Nimmo, K., van den Eijnden, J., Hessels, J.W.T., Gawroński, M.P., and Yang, J. Nature Astronomy (2020)

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AT 2017gbl: a dust obscured TDE candidate in a luminous infrared galaxy. Kool, E.C., Reynolds, T.M., Mattila, S., Kankare, E., Pérez-Torres, M.A., Efstathiou, A., Ryder, S., Romero-Cañizales, C., Lu, W., Heikkilä, T., Anderson, G.E., Berton, M., Bright, J., Cannizzaro, G., Eappachen, D., Fraser, M., Gromadzki, M., Jonker, P.G., Kuncarayakti, H., Lundqvist, P., Maeda, K., McDermid, R.M., Medling, A.M., Moran, S., Reguitti, A., Shahbandeh, M., Tsygankov, S., U, V., and Wevers, T. MNRAS 498, 2167 (2020)

A repeating fast radio burst source localized to a nearby spiral galaxy. Marcote, B., Nimmo, K., Hessels, J.W.T., Tendulkar, S.P., Bassa, C.G., Paragi, Z., Keimpema, A., Bhardwaj, M., Karuppusamy, R., Kaspi, V.M., Law, C.J., Michilli, D., Aggarwal, K., Andersen, B., Archibald, A.M., Bandura, K., Bower, G.C., Boyle, P.J., Brar, C., Burke-Spolaor, S., Butler, B.J., Cassanelli, T., Chawla, P., Demorest, P., Dobbs, M., Fonseca, E., Giri, U., Good, D.C., Gourdji, K., Josephy, A., Kirichenko, A.Y., Kirsten, F., Landecker, T.L., Lang, D., Lazio, T.J.W., Li, D.Z., Lin, H.-H., Linford, J.D., Masui, K., Mena-Parra, J., Naidu, A., Ng, C., Patel, C., Pen, U.-L., Pleunis, Z., Rafiei-Ravandi, M., Rahman, M., Renard, A., Scholz, P., Siegel, S.R., Smith, K.M., Stairs, I.H., Vanderlinde, K., and Zwaniga, A.V. Nature 577, 190 (2020)

The Nearby Luminous Transient AT2018cow: A Magnetar Formed in a Subrelativistically Expanding Nonjetted Explosion. Mohan, P., An, T., and Yang, J. ApJ 888, L24 (2020)

The e-MERGE Survey (e-MERLIN Galaxy Evolution Survey): overview and survey description. Muxlow, T.W.B., Thomson, A.P., Radcliffe, J.F., Wrigley, N.H., Beswick, R.J., Smail, I., McHardy, I.M., Garrington, S.T., Ivison, R.J., Jarvis, M.J., Prandoni, I., Bondi, M., Guidetti, D., Argo, M.K., Bacon, D., Best, P.N., Biggs, A.D., Chapman, S.C., Coppin, K., Chen, H., Garratt, T.K., Garrett, M.A., Ibar, E., Kneib, J.-P., Knudsen, K.K., Koopmans, L.V.E., Morabito, L.K., Murphy, E.J., Njeri, A., Pearson, C., Pérez-Torres, M.A., Richards, A.M.S., Röttgering, H.J.A., Sargent, M.T., Serjeant, S., Simpson, C., Simpson, J.M., Swinbank, A.M., Varenius, E., and Venturi, T. MNRAS 495, 1188 (2020)

Sub-milliarcsecond imaging of a bright flare and ejection event in the extragalactic jet 3C 111. Schulz, R., Kadler, M., Ros, E., Perucho, M., Krichbaum, T.P., Agudo, I., Beuchert, T., Lindqvist, M., Mannheim, K., Wilms, J., and Zensus, J.A. A&A 644, A85 (2020)

A parsec-scale radio jet launched by the central intermediate-mass black hole in the dwarf galaxy SDSS J090613.77+561015.2. Yang, J., Gurvits, L.I., Paragi, Z., Frey, S., Conway, J.E., Liu, X., and Cui, L. MNRAS 495, L71 (2020)

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A two-sided but significantly beamed jet in the supercritical accretion quasar IRAS F11119+3257. Yang, J., Paragi, Z., An, T., Baan, W.A., Mohan, P., and Liu, X. MNRAS 494, 1744 (2020)

Multiepoch VLBI of L Dwarf Binary 2MASS J0746+2000AB: Precise Mass Measurements and Confirmation of Radio Emission from Both Components. Zhang, Q., Hallinan, G., Brisken, W., Bourke, S., and Golden, A. ApJ 897, 11 (2020)

International authors (Astro VLBI)

A radio parallax to the black hole X-ray binary MAXI J1820+070. Atri, P., Miller-Jones, J.C.A., Bahramian, A., Plotkin, R.M., Deller, A.T., Jonker, P.G., Maccarone, T.J., Sivakoff, G.R., Soria, R., Altamirano, D., Belloni, T., Fender, R., Koerding, E., Maitra, D., Markoff, S., Migliari, S., Russell, D., Russell, T., Sarazin, C.L., Tetarenko, A.J., and Tudose, V. MNRAS 493, L81 (2020)

The nature of the methanol maser ring G23.657-00.127. II. Expansion of the maser structure. Bartkiewicz, A., Sanna, A., Szymczak, M., Moscadelli, L., van Langevelde, H.J., Wolak, P. A&A 637, A15 (2020)

Active galactic nuclei imaging programs of the RadioAstron mission. Bruni, G., Savolainen, T., Gómez, J.L., Lobanov, A.P., Kovalev, Y.Y., RadioAstron AGN Imaging Team, and KSP Team. Adv. Space Res. 65, 712 (2020)

VLBI observations of the G25.65+1.05 water maser superburst. Burns, R.A., Orosz, G., Bayandina, O., Surcis, G., Olech, M., MacLeod, G., Volvach, A., Rudnitskii, G., Hirota, T., Immer, K., Blanchard, J., Marcote, B., van Langevelde, H.J., Chibueze, J.O., Sugiyama, K., Kim, K.-T., Val`tts, I., Shakhvorostova, N., Kramer, B., Baan, W.A., Brogan, C., Hunter, T., Kurtz, S., Sobolev, A.M., Brand, J., and Volvach, L. MNRAS 491, 4069 (2020)

Searching for obscured AGN in z 2 submillimetre galaxies. Chen, H., Garrett, M.A., Chi, S., Thomson, A.P., Barthel, P.D., Alexander, D.M., Muxlow, T.W.B., Beswick, R.J., Radcliffe,∼ J.F., Wrigley, N.H., Guidetti, D., Bondi, M., Prandoni, I., Smail, I., McHardy, I., and Argo, M.K. A&A 638, A113 (2020)

An ALMA view of SO and SO2 around oxygen-rich AGB stars. Danilovich, T., Richards, A.M.S., Decin, L., Van de Sande, M., and Gottlieb, C.A. MNRAS 494, 1323 (2020)

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Very long baseline interferometry imaging of the advancing ejecta in the first gamma-ray nova V407 Cygni. Giroletti, M., Munari, U., Körding, E., Mioduszewski, A., Sokoloski, J., Cheung, C.C., Corbel, S., Schinzel, F., Sokolovsky, K., and O'Brien, T.J. A&A 638, A130 (2020)

Quasi-simultaneous radio and X-ray observations of Aql X-1 : probing low luminosities. Gusinskaia, N.V., Hessels, J.W.T., Degenaar, N., Deller, A.T., Miller-Jones, J.C.A., Archibald, A.M., Heinke, C.O., Moldón, J., Patruno, A., Tomsick, J.A., and Wijnands, R. MNRAS 492, 2858 (2020)

The jet of S5 0716 + 71 at μ as scales with RadioAstron. Kravchenko, E.V., Gómez, J.L., Kovalev, Y.Y., and Voitsik, P.A. Adv. Space Res. 65, 720 (2020)

Monitoring of the radio galaxy M 87 during a low-emission state from 2012 to 2015 with MAGIC. MAGIC Collaboration, Acciari, V.A., Ansoldi, S., Antonelli, L.A., Arbet Engels, A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., Barres de Almeida, U., Barrio, J.A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S.M., Colin, U., Colombo, E., Contreras, J.L., Cortina, J., Covino, S., D'Elia, V., da Vela, P., Dazzi, F., de Angelis, A., de Lotto, B., Delfino, M., Delgado, J., Depaoli, D., di Pierro, F., di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M.V., Font, L., Fruck, C., Fukami, S., García López, R.J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinović, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mićanović, S., Miceli, D., Minev, M., Miranda, J.M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nöthe, M., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J.M., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P.G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., Tsujimoto, S., Vagelli, V., van Scherpenberg, J., Vanzo, G., Acosta, M.V., Vigorito, C.F., Vitale, V., Vovk, I., Will, M., Zarić, D., Asano, K., Hada, K., Harris, D.E., Giroletti, M., Jermak, H.E., Madrid, J.P., Massaro, F., Richter, S., Spanier, F., Steele, I.A., and Walker, R.C. MNRAS 492, 5354 (2020)

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Long-term multi-frequency maser observations of the intermediate-mass young stellar object G107.298+5.639. Olech, M., Szymczak, M., Wolak, P., Gérard, E., and Bartkiewicz, A. A&A 634, A41 (2020)

Radio properties of the OH megamaser galaxy IRAS 02524+2046. Peng, H., Wu, Z., Zhang, B., Chen, Y., Zheng, X., Jiang, D., Shen, Z., Chen, X., and Sotnikova, Y.V. A&A 638, A78 (2020)

Observational Evidence for the Origin of High-energy Neutrinos in Parsec-scale Nuclei of Radio-bright Active Galaxies. Plavin, A., Kovalev, Y.Y., Kovalev, Y.A., and Troitsky, S. ApJ 894, 101 (2020)

VLBI observations of the H2O gigamaser in TXS 2226-184. Surcis, G., Tarchi, A., and Castangia, P. A&A 637, A57 (2020)

Localizing the γ-ray emitting region in the blazar TXS 2013+370. Traianou, E., Krichbaum, T.P., Boccardi, B., Angioni, R., Rani, B., Liu, J., Ros, E., Bach, U., Sokolovsky, K.V., Lisakov, M.M., Kiehlmann, S., Gurwell, M., and Zensus, J.A. A&A 634, A112 (2020)

Multiband RadioAstron space VLBI imaging of the jet in quasar S5 0836+710. Vega-García, L., Lobanov, A.P., Perucho, M., Bruni, G., Ros, E., Anderson, J.M., Agudo, I., Davis, R., Gómez, J.L., Kovalev, Y.Y., Krichbaum, T.P., Lisakov, M., Savolainen, T., Schinzel, F.K., and Zensus, J.A. A&A 641, A40 (2020)

The dying accretion and jet in a powerful radio galaxy of Hercules A. Wu, L.-H., Wu, Q.-W., Feng, J.-C., Lu, R.-S., and Fan, X.-L. Research in A&A 20, 122 (2020)

LOFAR, publications in refereed journals 2020

Swedish authors (LOFAR)

LOFAR 144-MHz follow-up observations of GW170817. Broderick, J.W., Shimwell, T.W., Gourdji, K., Rowlinson, A., Nissanke, S., Hotokezaka, K., Jonker, P.G., Tasse, C., Hardcastle, M.J., Oonk, J.B.R., Fender, R.P., Wijers, R.A.M.J., Shulevski, A., Stewart, A.J., ter Veen, S., Moss, V.A., van der Wiel, M.H.D., Nichols, D.A., Piette, A., Bell, M.E., Carbone, D., Corbel, S., Eislöffel, J., Grießmeier, J.-M., Keane, E.F., Law, C.J., Muñoz-Darias, T., Pietka, M., Serylak, M., van der Horst, A.J., van Leeuwen, J., Wijnands, R., Zarka, P., Anderson, J.M., Bentum, M.J., Blaauw, R., Brouw, W.N., Brüggen, M., Ciardi, B., de Vos, M., Duscha, S., Fallows, R.A., Franzen, T.M.O., Garrett, M.A., Gunst, A.W., Hoeft, M., Hörandel, J.R., Iacobelli, M., Jütte, E., Koopmans, L.V.E., Krankowski, A., Maat, P., Mann, G., Mulder, H., Nelles, A., Paas, H.,

72

Pandey-Pommier, M., Pekal, R., Reich, W., Röttgering, H.J.A., Schwarz, D.J., Smirnov, O., Soida, M., Toribio, M.C., van Haarlem, M.P., van Weeren, R.J., Vocks, C., Wucknitz, O., and Zucca, P. MNRAS 494, 5110 (2020)

Cassiopeia A, Cygnus A, Taurus A, and Virgo A at ultra-low radio frequencies. de Gasperin, F., Vink, J., McKean, J.P., Asgekar, A., Avruch, I., Bentum, M.J., Blaauw, R., Bonafede, A., Broderick, J.W., Brüggen, M., Breitling, F., Brouw, W.N., Butcher, H.R., Ciardi, B., Cuciti, V., de Vos, M., Duscha, S., Eislöffel, J., Engels, D., Fallows, R.A., Franzen, T.M.O., Garrett, M.A., Gunst, A.W., Hörandel, J., Heald, G., Hoeft, M., Iacobelli, M., Koopmans, L.V.E., Krankowski, A., Maat, P., Mann, G., Mevius, M., Miley, G., Morganti, R., Nelles, A., Norden, M.J., Offringa, A.R., Orrú, E., Paas, H., Pandey, V.N., Pandey-Pommier, M., Pekal, R., Pizzo, R., Reich, W., Rowlinson, A., Rottgering, H.J.A., Schwarz, D.J., Shulevski, A., Smirnov, O., Sobey, C., Soida, M., Steinmetz, M., Tagger, M., Toribio, M.C., van Ardenne, A., van der Horst, A.J., van Haarlem, M.P., van Weeren, R.J., Vocks, C., Wucknitz, O., Zarka, P., and Zucca, P. A&A 635, A150 (2020)

Searching for the largest bound atoms in space. Emig, K.L., Salas, P., de Gasperin, F., Oonk, J.B.R., Toribio, M.C., Mechev, A.P., Röttgering, H.J.A., and Tielens, A.G.G.M. A&A 634, A138 (2020)

A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances. Fallows, R.A., Forte, B., Astin, I., Allbrook, T., Arnold, A., Wood, A., Dorrian, G., Mevius, M., Rothkaehl, H., Matyjasiak, B., Krankowski, A., Anderson, J.M., Asgekar, A., Avruch, I.M., Bentum, M., Bisi, M.M., Butcher, H.R., Ciardi, B., Dabrowski, B., Damstra, S., de Gasperin, F., Duscha, S., Eislöffel, J., Franzen, T.M.O., Garrett, M.A., Grießmeier, J.-M., Gunst, A.W., Hoeft, M., Hörandel, J.R., Iacobelli, M., Intema, H.T., Koopmans, L.V.E., Maat, P., Mann, G., Nelles, A., Paas, H., Pandey, V.N., Reich, W., Rowlinson, A., Ruiter, M., Schwarz, D.J., Serylak, M., Shulevski, A., Smirnov, O.M., Soida, M., Steinmetz, M., Thoudam, S., Toribio, M.C., van Ardenne, A., van Bemmel, I.M., van der Wiel, M.H.D., van Haarlem, M.P., Vermeulen, R.C., Vocks, C., Wijers, R.A.M.J., Wucknitz, O., Zarka, P., Zucca, P. JSWSC 10, 10 (2020)

Constraining the intergalactic medium at z 9.1 using LOFAR Epoch of Reionization observations. Ghara, R., Giri, S.K., Mellema, G., Ciardi, B.,≈ Zaroubi, S., Iliev, I.T., Koopmans, L.V.E., Chapman, E., Gazagnes, S., Gehlot, B.K., Ghosh, A., Jelić, V., Mertens, F.G., Mondal, R., Schaye, J., Silva, M.B., Asad, K.M.B., Kooistra, R., Mevius, M., Offringa, A.R., Pandey, V.N., and Yatawatta, S. MNRAS 493, 4728 (2020)

73

Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR. Mertens, F.G., Mevius, M., Koopmans, L.V.E., Offringa, A.R., Mellema, G., Zaroubi, S., Brentjens, M.A., Gan, H., Gehlot, B.K., Pandey, V.N., Sardarabadi, A.M., Vedantham, H.K., Yatawatta, S., Asad, K.M.B., Ciardi, B., Chapman, E., Gazagnes, S., Ghara, R., Ghosh, A., Giri, S.K., Iliev, I.T., Jelić, V., Kooistra, R., Mondal, R., Schaye, J., and Silva, M.B. MNRAS 493, 1662 (2020)

Tight constraints on the excess radio background at z = 9.1 from LOFAR. Mondal, R., Fialkov, A., Fling, C., Iliev, I.T., Barkana, R., Ciardi, B., Mellema, G., Zaroubi, S., Koopmans, L.V.E., Mertens, F.G., Gehlot, B.K., Ghara, R., Ghosh, A., Giri, S.K., Offringa, A., and Pandey, V.N. MNRAS 498, 4178 (2020)

New constraints on the magnetization of the cosmic web using LOFAR Faraday rotation observations. O'Sullivan, S.P., Brüggen, M., Vazza, F., Carretti, E., Locatelli, N.T., Stuardi, C., Vacca, V., Vernstrom, T., Heald, G., Horellou, C., Shimwell, T.W., Hardcastle, M.J., Tasse, C., Röttgering, H. MNRAS 495, 2607 (2020)

The LOFAR view of intergalactic magnetic fields with giant radio galaxies. Stuardi, C., O'Sullivan, S.P., Bonafede, A., Brüggen, M., Dabhade, P., Horellou, C., Morganti, R., Carretti, E., Heald, G., Iacobelli, M., and Vacca, V. A&A 638, A48 (2020)

International authors (LOFAR)

A LOFAR census of non-recycled pulsars: extending to frequencies below 80 MHz. Bilous, A.V., Bondonneau, L., Kondratiev, V.I., Grießmeier, J.-M., Theureau, G., Hessels, J.W.T., Kramer, M., van Leeuwen, J., Sobey, C., Stappers, B.W., ter Veen, S., and Weltevrede, P. A&A 635, A75 (2020)

LOFAR observations of X-ray cavity systems. Bîrzan, L., Rafferty, D.A., Brüggen, M., Botteon, A., Brunetti, G., Cuciti, V., Edge, A.C., Morganti, R., Röttgering, H.J.A., and Shimwell, T.W. MNRAS 496, 2613 (2020)

A census of the pulsar population observed with the international LOFAR station FR606 at low frequencies (25-80 MHz). Bondonneau, L., Grießmeier, J.-M., Theureau, G., Bilous, A.V., Kondratiev, V.I., Serylak, M., Keith, M.J., and Lyne, A.G. A&A 635, A76 (2020)

Decoherence in LOFAR-VLBI beamforming. Bonnassieux, E., Edge, A., Morabito, L., and Bonafede, A. A&A 637, A51 (2020)

74

The Beautiful Mess in Abell 2255. Botteon, A., Brunetti, G., van Weeren, R.J., Shimwell, T.W., Pizzo, R.F., Cassano, R., Iacobelli, M., Gastaldello, F., Bîrzan, L., Bonafede, A., Brüggen, M., Cuciti, V., Dallacasa, D., de Gasperin, F., Di Gennaro, G., Drabent, A., Hardcastle, M.J., Hoeft, M., Mandal, S., Röttgering, H.J.A., and Simionescu, A. ApJ 897, 93 (2020)

A giant radio bridge connecting two galaxy clusters in Abell 1758. Botteon, A., van Weeren, R.J., Brunetti, G., de Gasperin, F., Intema, H.T., Osinga, E., Di Gennaro, G., Shimwell, T.W., Bonafede, A., Brüggen, M., Cassano, R., Cuciti, V., Dallacasa, D., Gastaldello, F., Mandal, S., Rossetti, M., and Röttgering, H.J.A. MNRAS 499, L11 (2020)

The multiphase and magnetized neutral hydrogen seen by LOFAR. Bracco, A., Jelić, V., Marchal, A., Turić, L., Erceg, A., Miville-Deschênes, M.-A., and Bellomi, E. A&A 644, L3 (2020)

Cosmic rays and magnetic fields in the core and halo of the starburst M82: implications for galactic wind physics. Buckman, B.J., Linden, T., and Thompson, T.A. MNRAS 494, 2679 (2020)

Low-frequency observations of the giant radio galaxy NGC 6251. Cantwell, T.M., Bray, J.D., Croston, J.H., Scaife, A.M.M., Mulcahy, D.D., Best, P.N., Brüggen, M., Brunetti, G., Callingham, J.R., Clarke, A.O., Hardcastle, M.J., Harwood, J.J., Heald, G., Heesen, V., Iacobelli, M., Jamrozy, M., Morganti, R., Orrú, E., O'Sullivan, S.P., Riseley, C.J., Röttgering, H.J.A., Shulevski, A., Sridhar, S.S., Tasse, C., and Van Eck, C.L. MNRAS 495, 143 (2020)

The LOFAR view of FR 0 radio galaxies. Capetti, A., Brienza, M., Baldi, R.D., Giovannini, G., Morganti, R., Hardcastle, M.J., Rottgering, H.J.A., Brunetti, G.F., Best, P.N., and Miley, G. A&A 642, A107 (2020)

Characterization of unresolved and unclassified sources detected in radio continuum surveys of the Galactic plane. Chakraborty, A., Roy, N., Wang, Y., Datta, A., Beuther, H., Medina, S.-N.X., Menten, K.M., Urquhart, J.S., Brunthaler, A., and Dzib, S.A. MNRAS 492, 2236 (2020)

Detection of Repeating FRB 180916.J0158+65 Down to Frequencies of 300 MHz. Chawla, P., Andersen, B.C., Bhardwaj, M., Fonseca, E., Josephy, A., Kaspi, V.M., Michilli, D., Pleunis, Z., Bandura, K.M., Bassa, C.G., Boyle, P.J., Brar, C., Cassanelli, T., Cubranic, D., Dobbs, M., Dong, F.Q., Gaensler, B.M., Good, D.C., Hessels, J.W.T., Landecker, T.L., Leung, C., Li, D.Z., Lin, H.-H., Masui, K., Mckinven, R., Mena-Parra, J., Merryfield, M., Meyers, B.W., Naidu, A., Ng, C., Patel, C., Rafiei-Ravandi, M., Rahman, M., Sanghavi, P., Scholz, P., Shin, K., Smith, K.M., Stairs, I.H., Tendulkar, S.P., Vanderlinde, K. ApJ 896, L41 (2020)

75

Subsecond Time Evolution of Type III Solar Radio Burst Sources at Fundamental and Harmonic Frequencies. Chen, X., Kontar, E.P., Chrysaphi, N., Jeffrey, N.L.S., Gordovskyy, M., Yan, Y., and Tan, B. ApJ 905, 43 (2020)

First Observation of a Type II Solar Radio Burst Transitioning between a Stationary and Drifting State. Chrysaphi, N., Reid, H.A.S., and Kontar, E.P. ApJ 893, 115 (2020)

Giant radio galaxies in the LOFAR Two-metre Sky Survey. I. Radio and environmental properties. Dabhade, P., Röttgering, H.J.A., Bagchi, J., Shimwell, T.W., Hardcastle, M.J., Sankhyayan, S., Morganti, R., Jamrozy, M., Shulevski, A., and Duncan, K.J. A&A 635, A5 (2020)

Reaching thermal noise at ultra-low radio frequencies. Toothbrush radio relic downstream of the shock front. de Gasperin, F., Brunetti, G., Brüggen, M., van Weeren, R., Williams, W.L., Botteon, A., Cuciti, V., Dijkema, T.J., Edler, H., Iacobelli, M., Kang, H., Offringa, A., Orrú, E., Pizzo, R., Rafferty, D., Röttgering, H., and Shimwell, T. A&A 642, A85 (2020)

Radio observations of HD 80606 near planetary periastron. II. LOFAR low band antenna observations at 30-78 MHz. de Gasperin, F., Lazio, T.J.W., and Knapp, M. A&A 644, A157 (2020)

Fast magnetic field amplification in distant galaxy clusters. Di Gennaro, G., van Weeren, R.J., Brunetti, G., Cassano, R., Brüggen, M., Hoeft, M., Shimwell, T.W., Röttgering, H.J.A., Bonafede, A., Botteon, A., Cuciti, V., Dallacasa, D., de Gasperin, F., Domínguez-Fernández, P., Enßlin, T.A., Gastaldello, F., Mandal, S., Rossetti, M., and Simionescu, A. Nature Astronomy (2020)

Dispersion measure variability for 36 millisecond pulsars at 150 MHz with LOFAR. Donner, J.Y., Verbiest, J.P.W., Tiburzi, C., Osłowski, S., Künsemöller, J., Bak Nielsen, A.-S., Grießmeier, J.-M., Serylak, M., Kramer, M., Anderson, J.M., Wucknitz, O., Keane, E., Kondratiev, V., Sobey, C., McKee, J.W., Bilous, A.V., Breton, R.P., Brüggen, M., Ciardi, B., Hoeft, M., van Leeuwen, J., and Vocks, C. A&A 644, A153 (2020)

Revisiting the Fraction of Radio-Loud Narrow Line Seyfert 1 Galaxies with LoTSS DR1. Fan, X.-L. Universe 6, 45 (2020)

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The AARTFAAC Cosmic Explorer: observations of the 21-cm power spectrum in the EDGES absorption trough. Gehlot, B.K., Mertens, F.G., Koopmans, L.V.E., Offringa, A.R., Shulevski, A., Mevius, M., Brentjens, M.A., Kuiack, M., Pandey, V.N., Rowlinson, A., Sardarabadi, A.M., Vedantham, H.K., Wijers, R.A.M.J., Yatawatta, S., and Zaroubi, S. MNRAS 499, 4158 (2020)

Radio galaxies and feedback from AGN jets. Hardcastle, M.J. and Croston, J.H. New Astronomy Reviews 88, 101539 (2020)

Radio Emission Reveals Inner Meter-Scale Structure of Negative Lightning Leader Steps. Hare, B.M., Scholten, O., Dwyer, J., Ebert, U., Nijdam, S., Bonardi, A., Buitink, S., Corstanje, A., Falcke, H., Huege, T., Hörandel, J.R., Krampah, G.K., Mitra, P., Mulrey, K., Neijzen, B., Nelles, A., Pandya, H., Rachen, J.P., Rossetto, L., Trinh, T.N.G., ter Veen, S., and Winchen, T. Phys. Rev. Lett. 124, 105101 (2020)

The great Kite in the sky: A LOFAR observation of the radio source in Abell 2626. Ignesti, A., Shimwell, T., Brunetti, G., Gitti, M., Intema, H., van Weeren, R.J., Hardcastle, M.J., Clarke, A.O., Botteon, A., Di Gennaro, G., Brüggen, M., Browne, I.W.A., Mandal, S., Röttgering, H.J.A., Cuciti, V., de Gasperin, F., Cassano, R., and Scaife, A.M.M. A&A 643, A172 (2020)

The life cycle of radio galaxies in the LOFAR Lockman Hole field. Jurlin, N., Morganti, R., Brienza, M., Mandal, S., Maddox, N., Duncan, K.J., Shabala, S.S., Hardcastle, M.J., Prandoni, I., Röttgering, H.J.A., Mahatma, V., Best, P.N., Mingo, B., Sabater, J., Shimwell, T.W., and Tasse, C. A&A 638, A34 (2020)

Long-term study of extreme giant pulses from PSR B0950+08 with AARTFAAC. Kuiack, M., Wijers, R.A.M.J., Rowlinson, A., Shulevski, A., Huizinga, F., Molenaar, G., and Prasad, P. MNRAS 497, 846 (2020)

Radio Echo in the Turbulent Corona and Simulations of Solar Drift-pair Radio Bursts. Kuznetsov, A.A., Chrysaphi, N., Kontar, E.P., and Motorina, G. ApJ 898, 94 (2020)

On Frequency-dependent Dispersion Measures and Extreme Scattering Events. Lam, M.T., Lazio, T.J.W., Dolch, T., Jones, M.L., McLaughlin, M.A., Stinebring, D.R., and Surnis, M. ApJ 892, 89 (2020)

Discovering the most elusive radio relic in the sky: diffuse shock acceleration caught in the act? Locatelli, N.T., Rajpurohit, K., Vazza, F., Gastaldello, F., Dallacasa, D., Bonafede, A., Rossetti, M., Stuardi, C., Bonassieux, E., Brunetti, G., Brüggen, M., and Shimwell, T. MNRAS 496, L48 (2020)

77

Fine Structure of a Solar Type II Radio Burst Observed by LOFAR. Magdalenić, J., Marqué, C., Fallows, R.A., Mann, G., Vocks, C., Zucca, P., Dabrowski, B.P., Krankowski, A., and Melnik, V. ApJ 897, L15 (2020)

Evolution of the Alfvén Mach number associated with a coronal mass ejection shock. Maguire, C.A., Carley, E.P., McCauley, J., and Gallagher, P.T. A&A 633, A56 (2020)

Revived fossil plasma sources in galaxy clusters. Mandal, S., Intema, H.T., van Weeren, R.J., Shimwell, T.W., Botteon, A., Brunetti, G., de Gasperin, F., Brüggen, M., Di Gennaro, G., Kraft, R., Röttgering, H.J.A., Hardcastle, M., and Tasse, C. A&A 634, A4 (2020)

Double-peak emission line galaxies in the SDSS catalogue. A minor merger sequence. Maschmann, D., Melchior, A.-L., Mamon, G.A., Chilingarian, I.V., and Katkov, I.Y. A&A 641, A171 (2020)

Characterizing EoR foregrounds: a study of the Lockman Hole region at 325 MHz. Mazumder, A., Chakraborty, A., Datta, A., Choudhuri, S., Roy, N., Wadadekar, Y., and Ishwara-Chandra, C.H. MNRAS 495, 4071 (2020)

Deep learning assisted data inspection for radio astronomy. Mesarcik, M., Boonstra, A.-J., Meijer, C., Jansen, W., Ranguelova, E., and van Nieuwpoort, R.V. MNRAS 496, 1517 (2020)

The LOFAR tied-array all-sky survey (LOTAAS): Characterization of 20 pulsar discoveries and their single-pulse behaviour. Michilli, D., Bassa, C., Cooper, S., Hessels, J.W.T., Kondratiev, V.I., Sanidas, S., Stappers, B.W., Tan, C.M., van Leeuwen, J., Cognard, I., Grießmeier, J.-M., Lyne, A.G., Verbiest, J.P.W., and Weltevrede, P. MNRAS 491, 725 (2020)

Reconstructing air shower parameters with LOFAR using event specific GDAS atmosphere. Mitra, P., Bonardi, A., Corstanje, A., Buitink, S., Krampah, G.K., Falcke, H., Hare, B.M., Hörandel, J.R., Huege, T., Mulrey, K., Nelles, A., Rachen, J.P., Rossetto, L., Scholten, O., ter Veen, S., Trinh, T.N.G., Winchen, T., and Pandya, H. Astropart. Phys. 123, 102470 (2020)

The Massive and Distant Clusters of WISE Survey. IX. High Radio Activity in a Merging Cluster. Moravec, E., Gonzalez, A.H., Dicker, S., Alberts, S., Brodwin, M., Clarke, T.E., Connor, T., Decker, B., Devlin, M., Eisenhardt, P.R.M., Mason, B.S., Mo, W., Mroczkowski, T., Pope, A., Romero, C.E., Sarazin, C., Sievers, J., Stanford, S.A., Stern, D., Wylezalek, D., and Zago, F. ApJ 898, 145 (2020)

78

The Massive and Distant Clusters of WISE Survey. VII. The Environments and Properties of Radio Galaxies in Clusters at z 1. Moravec, E., Gonzalez, A.H., Stern, D., Clarke, T., Brodwin, M., Decker, B., Eisenhardt, P.R.M., Mo, W., Pope,∼ A., Stanford, S.A., and Wylezalek, D. ApJ 888, 74 (2020)

On the cosmic-ray energy scale of the LOFAR radio telescope. Mulrey, K., Buitink, S., Corstanje, A., Falcke, H., Hare, B.M., Hörandel, J.R., Huege, T., Krampah, G.K., Mitra, P., Nelles, A., Pandya, H., Rachen, J.P., Scholten, O., ter Veen, S., Thoudam, S., Trinh, T.N.G., and Winchen, T. JCAP 2020, 17 (2020)

Discovery of a Gamma-Ray Black Widow Pulsar by GPU-accelerated Einstein@Home. Nieder, L., Clark, C.J., Kandel, D., Romani, R.W., Bassa, C.G., Allen, B., Ashok, A., Cognard, I., Fehrmann, H., Freire, P., Karuppusamy, R., Kramer, M., Li, D., Machenschalk, B., Pan, Z., Papa, M.A., Ransom, S.M., Ray, P.S., Roy, J., Wang, P., Wu, J., Aulbert, C., Barr, E.D., Beheshtipour, B., Behnke, O., Bhattacharyya, B., Breton, R.P., Camilo, F., Choquet, C., Dhillon, V.S., Ferrara, E.C., Guillemot, L., Hessels, J.W.T., Kerr, M., Kwang, S.A., Marsh, T.R., Mickaliger, M.B., Pleunis, Z., Pletsch, H.J., Roberts, M.S.E., Sanpa-arsa, S., and Steltner, B. ApJ 902, L46 (2020)

The LOFAR Long-Baseline Calibrator Survey Classification. Nikolajevs, A. and Prūsis, K. Latvian Journal of Physics and Technical Sciences 57, 34 (2020)

Redshifted 21-cm emission signal from the halos in Dark Ages. Novosyadlyj, B., Shulga, V., Kulinich, Y., and Han, W. Physics of the Dark Universe 27, 100422 (2020)

Alignment in the orientation of LOFAR radio sources. Osinga, E., Miley, G.K., van Weeren, R.J., Shimwell, T.W., Duncan, K.J., Hardcastle, M.J., Mechev, A.P., Röttgering, H.J.A., Tasse, C., and Williams, W.L. A&A 642, A70 (2020)

Radio relic and the diffuse emission trail discovered in low-mass galaxy cluster Abell 1697. Paul, S., Salunkhe, S., Sonkamble, S., Gupta, P., Mroczkowski, T., and Raychaudhury, S. A&A 633, A59 (2020)

Study of spider pulsar binary eclipses and discovery of an eclipse mechanism transition. Polzin, E.J., Breton, R.P., Bhattacharyya, B., Scholte, D., Sobey, C., and Stappers, B.W. MNRAS 494, 2948 (2020)

Differences in radio emission from similar M dwarfs in the binary system Ross 867-8. Quiroga-Nuñez, L.H., Intema, H.T., Callingham, J.R., Villadsen, J., van Langevelde, H.J., Jagannathan, P., Shimwell, T.W., and Boven, E.P. A&A 633, A130 (2020)

79

New mysteries and challenges from the Toothbrush relic: wideband observations from 550 MHz to 8 GHz. Rajpurohit, K., Hoeft, M., Vazza, F., Rudnick, L., van Weeren, R.J., Wittor, D., Drabent, A., Brienza, M., Bonnassieux, E., Locatelli, N., Kale, R., and Dumba, C. A&A 636, A30 (2020)

A perfect power-law spectrum even at the highest frequencies: The Toothbrush relic. Rajpurohit, K., Vazza, F., Hoeft, M., Loi, F., Beck, R., Vacca, V., Kierdorf, M., van Weeren, R.J., Wittor, D., Govoni, F., Murgia, M., Riseley, C.J., Locatelli, N., Drabent, A., and Bonnassieux, E. A&A 642, L13 (2020)

The optical luminosity function of LOFAR radio-selected quasars at 1.4 ≤ z ≤ 5.0 in the NDWFS-Boötes field. Retana-Montenegro, E. and Röttgering, H.J.A. A&A 636, A12 (2020)

Fundamental differences in the radio properties of red and blue quasars: insight from the LOFAR Two-metre Sky Survey (LoTSS). Rosario, D.J., Fawcett, V.A., Klindt, L., Alexander, D.M., Morabito, L.K., Fotopoulou, S., Lusso, E., and Calistro Rivera, G. MNRAS 494, 3061 (2020)

The Significance of Low-frequency Interferometric Observations for the GPS Pulsar Flux Estimation: The Case of J1740+1000. Rożko, K., Kijak, J., Chyży, K., Lewandowski, W., Shimwell, T., Sridhar, S.S., Curyło, M., Krankowski, A., and Błaszkiewicz, L. ApJ 903, 144 (2020)

Tied-array holography with LOFAR. Salas, P., Brentjens, M.A., Bordenave, D.D., Oonk, J.B.R., and Röttgering, H.J.A. A&A 635, A207 (2020)

The duty cycle of radio galaxies revealed by LOFAR: remnant and restarted radio source populations in the Lockman Hole. Shabala, S.S., Jurlin, N., Morganti, R., Brienza, M., Hardcastle, M.J., Godfrey, L.E.H., Krause, M.G.H., and Turner, R.J. MNRAS 496, 1706 (2020)

One- and two-point source statistics from the LOFAR Two-metre Sky Survey first data release. Siewert, T.M., Hale, C., Bhardwaj, N., Biermann, M., Bacon, D.J., Jarvis, M., Röttgering, H.J.A., Schwarz, D.J., Shimwell, T., Best, P.N., Duncan, K.J., Hardcastle, M.J., Sabater, J., Tasse, C., White, G.J., and Williams, W.L. A&A 643, A100 (2020)

LOFAR view of NGC 3998, a sputtering AGN. Sridhar, S.S., Morganti, R., Nyland, K., Frank, B.S., Harwood, J., and Oosterloo, T. A&A 634, A108 (2020)

80

GMRT observations of IC 711 - the longest head-tail radio galaxy known. Srivastava, S. and Singal, A.K. MNRAS 493, 3811 (2020)

LOFAR detectability of prompt low-frequency radio emission during gamma-ray burst X-ray flares. Starling, R.L.C., Rowlinson, A., van der Horst, A.J., and Wijers, R.A.M.J. MNRAS 494, 5787 (2020)

CHANG-ES. XXI. Transport processes and the X-shaped magnetic field of NGC 4217: off- center superbubble structure. Stein, Y., Dettmar, R.-J., Beck, R., Irwin, J., Wiegert, T., Miskolczi, A., Wang, Q.D., English, J., Henriksen, R., Radica, M., and Li, J.-T. A&A 639, A111 (2020)

The LOFAR Tied-Array all-sky survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR. Tan, C.M., Bassa, C.G., Cooper, S., Hessels, J.W.T., Kondratiev, V.I., Michilli, D., Sanidas, S., Stappers, B.W., van Leeuwen, J., Donner, J.Y., Grießmeier, J.-M., Kramer, M., Tiburzi, C., Weltevrede, P., Ciardi, B., Hoeft, M., Mann, G., Miskolczi, A., Schwarz, D.J., Vocks, C., and Wucknitz, O. MNRAS 492, 5878 (2020)

LOFAR radio search for single and periodic pulses from M 31. van Leeuwen, J., Mikhailov, K., Keane, E., Coenen, T., Connor, L., Kondratiev, V., Michilli, D., and Sanidas, S. A&A 634, A3 (2020)

Direct Radio Discovery of a Cold Brown Dwarf. Vedantham, H.K., Callingham, J.R., Shimwell, T.W., Dupuy, T., Best, W.M.J., Liu, M.C., Zhang, Z., De, K., Lamy, L., Zarka, P., Röttgering, H.J.A., and Shulevski, A. ApJ 903, L33 (2020)

Coherent radio emission from a quiescent red dwarf indicative of star-planet interaction. Vedantham, H.K., Callingham, J.R., Shimwell, T.W., Tasse, C., Pope, B.J.S., Bedell, M., Snellen, I., Best, P., Hardcastle, M.J., Haverkorn, M., Mechev, A., O'Sullivan, S.P., Röttgering, H.J.A., and White, G.J. Nature Astronomy 4, 577 (2020)

Radio constraints on dark matter annihilation in Canes Venatici I with LOFAR. Vollmann, M., Heesen, V., W. Shimwell, T., Hardcastle, M.J., Brüggen, M., Sigl, G., and J. A. Röttgering, H. MNRAS 496, 2663 (2020)

Pulsar candidate selection using pseudo-nearest centroid neighbour classifier. Xiao, J., Li, X., Lin, H., and Qiu, K. MNRAS 492, 2119 (2020)

81

Interferometric imaging with LOFAR remote baselines of the fine structures of a solar type- IIIb radio burst. Zhang, P., Zucca, P., Sridhar, S.S., Wang, C., Bisi, M.M., Dabrowski, B., Krankowski, A., Mann, G., Magdalenic, J., Morosan, D.E., and Vocks, C. A&A 639, A115 (2020)

The Frequency Drift and Fine Structures of Solar S-bursts in the High Frequency Band of LOFAR. Zhang, P., Zucca, P., Wang, C., Bisi, M.M., Da̧ browski, B., Fallows, R.A., Krankowski, A., Magdalenic, J., Mann, G., Morosan, D.E., and Vocks, C. ApJ 891, 89 (2020)

Link between radio-loud AGNs and host-galaxy shape. Zheng, X.C., Röttgering, H.J.A., Best, P.N., van der Wel, A., Hardcastle, M.J., Williams, W.L., Bonato, M., Prandoni, I., Smith, D.J.B., and Leslie, S.K. A&A 644, A12 (2020)

Geoscience, Publications in refereed journals 2020, using the infrastructure at the Onsala site

Swedish authors (Geoscience)

The third realization of the International Celestial Reference Frame by very long baseline interferometry. Charlot, P., Jacobs, C., Gordon, D., Lambert, S., de Witt, A., Böhm, J., Fey, A., Heinkelmann, R., Skurikhina, E., Titov, O., Arias, F., Bolotin, S., Bourda, G., Ma, C., Malkin, Z., Nothnagel, A., Mayer, D., MacMillan, D., Nilsson, T., Gaume, R. A&A 644, A159 (2020)

SNR-based GNSS reflectometry for coastal sea-level altimetry: results from the first IAG inter-comparison campaign. Geremia-Nievinski, F., Hobiger, T., Haas, R. et al. J Geod 94, 70 (2020)

Erfassung der Hauptreflektordeformation eines Radioteleskops durch UAV-gestützte Nahbereichsphotogrammetrie. Greiwe, A., Brechtken, R., Lösler, M., Eschelbach, C., Haas, R. Publ. DGPF. 29 346 (2020)

Quantifying the Uncertainty in Ground-Based GNSS-Reflectometry Sea Level Measurements Purnell, D., Gomez, N., Chan, N.H., Strandberg, J., Holland, D.M., Hobiger, T. JSTARS 13, 4419 (2020)

82

Superconducting gravimeter and seismometer shedding light on FG5’s offsets, trends and noise: what observations at Onsala Space Observatory can tell us. Scherneck, H.-G., Rajner, M., Engfeldt, A. J Geod 94, 80 (2020)

Upper mantle density and surface gravity change in Fennoscandia, determined from GRACE monthly data. Sjöberg, L.E., Bagherbandia, M. Tectonophysics 782-783, 228428 (2020)

Can We Measure Sea Level With a Tablet Computer? Strandberg, J., Haas, R. IEEE Geoscience and Remote Sensing Letters 17, 1876 (2020)

Homogenizing GPS integrated water vapor time series: Benchmarking break detection methods on synthetic data sets. Van Malderen, R., Pottiaux, E., Klos, A., Domonkos, P., Elias, M., Ning, T., et al. Earth Space Science 7, e2020EA001121 (2020)

International authors (Geoscience)

Benefits of combining GPS and GLONASS for measuring ocean tide loading displacement Abbaszadeh, M., Clarke, P.J., Penna, N.T. J Geod 94, 63 (2020)

On the interoperability of IGS products for precise point positioning with ambiguity resolution. Banville, S., Geng, J., Loyer, S., Schaer, S., Springer, T., Strasser, S. J Geod 94, 10 (2020)

On the organization of CONT17. Behrend, D., Thomas, C., Gipson, J. et al. J Geod 94, 100 (2020)

Achievements of the First 4 Years of the International Geodynamics and Earth Tide Service (IGETS) 2015–2019. Boy, J.P., Barriot, J.P., Förste, C., Voigt, C., Wziontek, H. International Association of Geodesy Symposia (2020)

Benefits of non-tidal loading applied at distinct levels in VLBI analysis. Glomsda, M., Bloßfeld, M., Seitz, M. et al. J Geod 94, 90 (2020)

Evaluation of VLBI Observations with Sensitivity and Robustness Analyses. Küreç Nehbit, P., Heinkelmann, R., Schuh, H., Glaser, S., Lunz, S., Mammadaliyev, N., Balidakis, K., Konak, H., Tanır Kayıkçı, E. Mathematics 8, 939 (2020)

83

Analysis of the Results of 20 Years of Activity of the International VLBI Service for Geodesy and Astrometry. Malkin, Z.M. Astronomy Reports 64, 168 (2020)

Overview of CODE’s MGEX solution with the focus on Galileo. Prange, L., Villiger, A., Sidorov, D., Schaer, S., Beutler, G., Dach, R., Jäggi, A. Adv. Space Res. 66, 2786 (2020)

Inter-Comparison of Ground Gravity and Vertical Height Measurements at Collocated IGETS Stations. Rosat, S., Boy, J.P., Bogusz, J., Klos A. International Association of Geodesy Symposia (2020)

Optimizing schedules for the VLBI global observing system. Schartner, M., Böhm J. J Geod 94, 12 (2020)

Optimal antenna locations of the VLBI Global Observing System for the estimation of Earth orientation parameters. Schartner, M., Böhm, J., Nothnagel, A. Earth Planets Space 72, 87 (2020)

GPS III Vespucci: Results of half a year in orbit. Steigenberger, P., Thoelert, S., Montenbruck, O. Adv. Space Res. 66, 2773 (2020)

M2 constituent of ocean tide loading displacements from VLBI CONT14 hourly sessions. Teke, K. Annals of Geophysics 63, 3 (2020)

Resolving VLBI correlator ambiguity in the time delay model improves precision of geodetic measurements. Titov, O., Melnikov, A., Lopez, Y. PASA 37, E050 (2020)

Evaluating the impact of CNES real-time ionospheric products on multi-GNSS single- frequency positioning using the IGS real-time service. Wang, A., Chen, J., Zhang, Y., Meng, L., Wang, B., Wang, J. Adv. Space Res. 66, 2516 (2020)

84

Onsala 20 m telescope, single-dish observations, publications in refereed journals 2020

Swedish authors (OSO 20 m)

Detection of two bright radio bursts from magnetar SGR 1935 + 2154. Kirsten, F., Snelders, M.P., Jenkins, M., Nimmo, K., van den Eijnden, J., Hessels, J.W.T., Gawroński, M.P., and Yang, J. Nature Astronomy (2020)

A Survey of High Mass Star Forming Regions in the Lines of Deuterated Molecules. Trofimova, E.A., Zinchenko, I.I., Zemlyanukha, P.M., Thomasson, M. Astronomy Reports 64, 244 (2020)

International authors (OSO 20 m)

The ISM scaling relations in DustPedia late-type galaxies: A benchmark study for the Local Universe. Casasola, V., Bianchi, S., De Vis, P., Magrini, L., Corbelli, E., Clark, C.J.R., Fritz, J., Nersesian, A., Viaene, S., Baes, M., Cassarà, L.P., Davies, J., De Looze, I., Dobbels, W., Galametz, M., Galliano, F., Jones, A.P., Madden, S.C., Mosenkov, A.V., Trčka, A., and Xilouris, E. A&A 633, A100 (2020)

Central molecular zones in galaxies: 12CO-to-13CO ratios, carbon budget, and X factors. Israel, F.P. A&A 635, A131 (2020)

The Physical Parameters of Clumps Associated with Class I Methanol Masers. Ladeyschikov, D.A., Urquhart, J.S., Sobolev, A.M., Breen, S.L., and Bayandina, O.S. ApJ 160, 213 (2020)

NGC 7538 IRS1—an O Star Driving an Ionized Jet and Giant N─S Outflow. Sandell, G., Wright, M., Güsten, R., Wiesemeyer, H., Reyes, N., Mookerjea, B., and Corder, S. ApJ 904, 139 (2020)

Technical publications in refereed journals 2020, about, e.g., receiver development, by OSO staff

Single-Layer Dichroic Filters for Multifrequency Receivers at THz Frequencies. Montofre, D., Khudchenko, A., Mena, F.P., Hesper, R., Baryshev, A.M. IEEE Transactions on Terahertz Science and Technology 10, 690 (2020)

Wideband 67−116 GHz receiver development for ALMA Band 2. Yagoubov, P., Mroczkowski, T., Belitsky, V., Cuadrado-Calle, D., Cuttaia, F., Fuller, G. A., Gallego, J. -D., Gonzalez, A., Kaneko, K., Mena, P., Molina, R., Nesti, R., Tapia, V., Villa, F., Beltrán, M., Cavaliere, F., Ceru, J., Chesmore, G. E., Coughlin, K., De Breuck, C. Fredrixon, M., George, D., Gibson, H., Golec, J., Josaitis, A., Kemper, F., Kotiranta, M.,

85

Lapkin, I., López-Fernández, I., Marconi, G., Mariotti, S., McGenn, W., McMahon, J., Murk, A., Pezzotta, F., Phillips, N., Reyes, N., Ricciardi, S., Sandri, M., Strandberg, M., Terenzi, L., Testi, L., Thomas, B., Uzawa, Y., Viganò, D., Wadefalk, N. A&A 634, A46 (2020)

Dielectrically Loaded Quad-Ridge Flared Horn for Beamwidth Control Over Decade Bandwidth-Optimization, Manufacture, and Measurement. Flygare, J., Pantaleev, M. IEEE Transactions on Antennas and Propagation 68, 207 (2020)

Radio observatories and instrumentation used in space weather science and operations. Carley, E.P., Baldovin, C., Benthem, P., Bisi, M.M., Fallows, R.A., Gallagher, P.T., Olberg, M., Rothkaehl, H., Vermeulen, R., Vilmer, N., Barnes, D. Journal of Space Weather and Space Climate 10, 7 (2020)

Waveguide-to-substrate transition based on unilateral substrateless finline structure: Design, fabrication, and characterization. López, C., Desmaris, V., Meledin, D., Pavolotsky, A., Belitsky, V. IEEE Transactions on Terahertz Science and Technology 10, 668 (2020)

Surface modification of polytetrafluoroethylene thin films by non-coherent UV light and water treatment for electrowetting applications. López, C.D., Cedeño-Mata, M., Dominguez-Pumara, M., Bermejo, S. Progress in Organic Coatings 149, 105593 (2020)

Ultrawideband Conical Log-Spiral Circularly Polarized Feed for Radio Astronomy. Abdalmalak, K.A., Santamaría Botello, G., Llorente-Romano, S., Rivera-Lavado, A., Flygare, J., López Fernándezs, J. A., Serna Puente, J. M., García-Castillo, L. E., Segovia- Vargas, D., Pantaleev, M., García-Muñoz, L. E. IEEE Transactions on Antennas and Propagation 68, 1995 (2020)

Design and Implementation of a Compact 90 degrees Waveguide Twist With Machining Tolerant Layout. López, C., Desmaris, V., Meledin, D., Pavolotsky, A., Belitsky, V. IEEE Microwave and Wireless Components Letters 30, 741 (2020)

86

Key numbers (nyckeltal)

Please see the following pages. An excel file with the same information is provided separately.

87

Infrastrukturens namn: OSO Diarienummer: 2017-00648 Respondent (namn): John Conway Respondent (epost): [email protected] Respondent (telefon): 031-772 5503 Avser år: 2020

Katergorier av nyckeltal 1 Anställda (enskilda individer eller FTE) 2 Projekt (representerade av en PI) 3 Användare (enskilda individer) 4 Kvantitet av användning 5Output

1 Anställda vid infrastrukturen Förklaringar till tabell 2, 3 och 4: 1.1 Enskilda individer Totalt 48 ALMA: Tabell 2: Projekt med en nordisk PI. Cycle 7 (observationer oktober 2019 - september 2020). Genomförda = projekt med minst ett levererat dataset. Astro user support / ARCnode (Modul 2) 5 Tabell 3: Nordiska användare på alla projekt (även projekt med icke-nordisk PI). Cycle 7. APEX svensk tid (Modul 3) 4 Tabell 4: OSO har inte tillgång till information om observerade timmar, i stället rapporteras här antal projekt. Astronomisk VLBI (Modul 4) 5 APEX: Alla projekt på svensk tid. Period P105 (observationer 2020). P.g.a.coronapandemin genomfördes inget Call for proposals för P106. LOFAR (Modul 5) 2 Astronomisk VLBI: Alla proposaler inskickade 2020. Alla observationer utförda 2020. Geovetenskap (Modul 6) 11 LOFAR: Alla projekt i Cycle 13 och 14 (observationer november 2019 - november 2020). Utveckling av mm-mottagare (Modul 8) 7 Utveckling av cm-mottagare (Modul 9) 7 Alla projekt observerade under aktuell period rapporteras. I undantagsfall är projekten inte avslutade (vilket OSO saknar information om). Ledning (Modul 1) 3 Övriga tjänster (Modul 10) 4 För geoverksamheten kan nyckeltal av detta slag inte rapporteras (se aktivitetsrapporten för detaljer). Dock rapporterar vi observationstid med geodetisk VLBI i tabell 4. 1.2 FTE Totalt 33,1 Gråmarkerade fält är inte aktuella för OSO. Astro user support / ARCnode (Modul 2) 3,8 APEX svensk tid (Modul 3) 3,3 Astronomisk VLBI (Modul 4) 4,1 LOFAR (Modul 5) 0,8 Geovetenskap (Modul 6) 4,1 Utveckling av mm-mottagare (Modul 8) 5,4 Utveckling av cm-mottagare (Modul 9) 6,4 Ledning (Modul 1) 1,9 Övriga tjänster (Modul 10) 3,3

a. Alla projekt b. Typ av hemvist för alla PI c. Typ av akademisk hemvist för PI (endast akademiska hemvister) Akademisk Kommersiell Offentlig Övriga 2 Projekt Totalt Män Kvinnor Totalt Män Kvinnor Totalt Totalt Totalt Chalmers Annat svenskt lärosäte Internationell 2.1 Sökta projekt Totalt 325 218 107 325 218 107 79 5 241 ALMA (projekt med nordisk PI) 94 59 35 94 59 35 57 5 32 APEX svensk tid 40 21 19 40 21 19 17 0 23 Astronomisk VLBI 95 75 20 95 75 20 2 0 93 LOFAR 96 63 33 96 63 33 3 93 2.2 Genomförda projekt Totalt 118 87 31 118 87 31 9 0 109 ALMA (projekt med nordisk PI) 6 5 1 6 5 1 1 0 5 APEX svensk tid 8 4 4 8 4 4 3 0 5 Astronomisk VLBI 61 45 16 61 45 16 3 0 58 LOFAR 43 33 10 43 33 10 2 0 41 d. Alla användare e. Typ av hemvist för alla användare f. Typ av akademisk hemvist för användare (endast akad. hemvister) Akademisk Kommersiell Offentlig Övriga 3 Användare Totalt Män Kvinnor Totalt Män Kvinnor Totalt Totalt Totalt Chalmers Annat svenskt lärosäte Internationell 3.1 Sökta projekt Totalt 955 711 244 955 711 244 53 34 868 ALMA (nordiska användare, alla projekt) 132 90 40 132 90 40 37 28 67 APEX svensk tid 124 84 40 124 84 40 28 2 94 Astronomisk VLBI 424 336 88 424 336 88 7 6 411 LOFAR 377 276 101 377 276 101 8 2 367 3.2 Genomförda projekt Totalt 632 474 158 632 474 158 36 14 582 ALMA (nordiska användare, alla projekt) 49 36 13 49 36 13 16 8 25 APEX svensk tid 45 30 15 45 30 15 17 0 28 Astronomisk VLBI 324 248 76 324 248 76 8 5 311 LOFAR 275 208 67 275 208 67 8 1 266

g. Total kvantitet per typ av tillgång till infrastrukturen h. Kvantitet av tillgång för akademiska projekt Alla användare Fysisk tillgång till infrastruktur 4 Typ och kvantitet av tillgång Fysisk Data Prover Totalt Män Kvinnor 4.1 Användning under året Totalt n/a n/a n/a n/a ALMA (antal projekt med nordisk PI) 6 806 GB 6 5 1 APEX svensk tid (h) 79 3388 records 79 29 50 Astronomisk VLBI (h) 1291 639 TB/40 TB 1291 990 301 LOFAR (h) 3202 6 PB/7 PB 3202 2910 292 Geodetisk VLBI (h) 1717 1717 n/a n/a

5 Output 5.1 Publikationer Se bifogad lista 5.2 Patent n/a