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Report on the activities in 2019 of Onsala Space Observatory The Swedish National Infrastructure for Radio Astronomy

This report presents the activities at Onsala Space Observatory (OSO) during 2019, 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.

The first image of a black hole: the shadow of the supermassive black hole in the centre of the galaxy Messier 87, as imaged by the Event Horizon Telescope. The telescopes contributing to the image include ALMA and APEX. Credit: EHT Collaboration.

Onsala, 15th June 2020

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 R&D 5. SKA – The Square Kilometre Array 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 2019 Key numbers (nyckeltal)

1 Operations

During 2019 Onsala Space Observatory (OSO) operated the following facilities:

– The Onsala 20 m telescope for astronomical Very Long Baseline Interferometry (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

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 2019 activity plan without any major problems, details are given below:

Onsala 20 m telescope: The 20 m telescope was used in accordance with the 2019 activity plan without any major divergence. The telescope participated in 45 geodetic 24-hour campaigns, 13 astronomical single-dish projects, 5 extended astronomical VLBI sessions, 3+1 short astronomical/geodetic VLBI out-of-session type observations, and 3 teaching/outreach observations. In addition, a few days were dedicated to coordinated geodetic tests with the Onsala Twin Telescopes. Maintenance (including technical observations) occurred at normal levels. Upgrade-targeted technical activities included: improving the pointing model, evaluating sensor replacements for the subreflector, replacing the telescope control computer, and completing the migration to new telescope control software (Bifrost). An advanced mapping capability was added to Bifrost in the autumn of 2019; it is estimated that 5 days of telescope testing was used for commissioning this function and other Bifrost features.

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 2019, The OTT was used for 40 VGOS sessions of different kinds, for a total observing time of approximately 700 hours. See Sect. 1.3 for details.

APEX: Swedish APEX observations were conducted on 26 days, organized in three runs, during 2019. To perform service mode observations, which are organized as three observing shifts per day (afternoon, night, morning), OSO typically sends four observers per run. A panel upgrade of the telescope surface was carried out in 2019, in addition the SEPIA receiver was moved from the A-cabin guest receiver position to a facility receiver position, requiring the installation of new relay optics. Additional setting of the telescope surface panels is scheduled for 2020 to further improve telescope surface accuracy and hence the high frequency performance of the telescope.

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 Netherlands. 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, APEX 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 while for APEX observations were scheduled by the Event Horizon

Telescope consortium). Geodetic VLBI observations using Onsala telescopes (20m 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: 35 days of astronomical VLBI 45 days of geodetic VLBI 90 days of single-dish astronomy

– The Onsala 25 m telescope: 59 days of regular astronomical VLBI (in addition, observations were carried out on 81 days for the VLBI-campaign PRECISE, see Sect. 4.3)

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

– The APEX telescope: 26 days of single-dish astronomy on Swedish time

– The LOFAR station: 209 days (ILT), 154 days (local)

Note that time for “normal” technical service, pointing, etc. are not included in the above figures. These service activities amounted to about 15 and 13 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.

1.2 Nordic ARC node [Module 2]

In 2019 the Nordic ALMA Regional Centre (ARC) provided support to the Nordic astronomical communities in all the many aspects of the ALMA user experience, from proposal preparation to data reduction and analysis of PI and Archival data. Nordic ARC staff provided support to users to submit proposals for the Cycle 7 Call for Proposals (deadline April 2019) by all possible means, including visits to the major astronomy institutes in the region. The total number of submitted proposals worldwide in Cycle 7 was 1787, for the first time this number did not supersede the previous cycle figure. 195 proposals were submitted by Swedish PI/co-Is, 74 of which were awarded time. In the autumn of 2019, ALMA opened a supplemental Call for Proposal for filler projects for the ALMA Compact Array (deadline October 2019). 249 proposals were submitted for that call. Swedish PI/co-Is submitted 25 proposals out of which 10 were granted observing time. Approved projects from the Nordic countries get assigned staff from the Nordic ARC as contact scientists; their role being to act as the point of contact between PIs and the Observatory during the full life cycle of a project. In 2019, data reduction and quality assessment of most of PI observations was carried by the Joint ALMA Observatory (JAO) in Chile or at ESO using the ALMA Science Pipeline. In contrast Nordic ARC staff mostly contributed to the data reduction effort of non-standard Nordic projects that were not manageable by the Pipeline, such as Polarization or High- Frequency projects. In total, the data reduction and quality assessment of 10 projects was performed by Nordic ARC staff. In the past year, the node supported 11 Face-to-Face visits of Swedish researchers for data reduction of ALMA projects, including archive research. Each project has taken an average of one week of full-time support, followed by remote support during a longer period until the

project goals were achieved. This increased support time per project is due to the increased complexity and computing time requirements (e.g, array combination, large mosaics, etc.) of projects choosing face-to-face support. As well as supporting individual observations staff also participated in providing advice to the Nordic led ESO ALMA Development study “High- Cadence Imaging of the Sun”. Besides the regular collaboration among nodes, two specific events during the year brought together staff from all the different European ARC Network nodes. The Nordic ARC node manager and deputy manager participated in the European ARC Representatives meeting in Jodrell Bank (UK) in March. This annual meeting serves as a discussion forum on the status of the network, next cycle procedures, general ALMA updates and future developments. In October 2019, EU the ‘ARC All-hands’ meeting gathered together all the European ARC staff. During this meeting network progress updates and discussions were held over 3 days (see section 10). NordicARC staff also attended the ALMA Science Conference that took place in Cagliari (October 2019). The Nordic ARC continued the support and maintenance of the Advanced Data Analysis Tools (https://www.oso.nordic-alma.se/software-tools.php). The modelling engine in UVMULTIFIT is being used for the development of advanced calibration algorithms within the EU H2020 RadioNet project’s working package RINGS (Radio Interferometry Next Generation Software). The Nordic ARC also hosted a 3-day workshop in September on the topic of Software Tools development for ALMA within the European ARC network. During the year two staff members of the Nordic ARC left their positions in the node, and one of them finished employment at OSO/Chalmers. At the same time, two new staff members were recruited. As a consequence, the node went through a reorganization and the temporary lack of human resources stalled any further development of new software tools during the latter part of the year. Resources were instead devoted to the support and maintenance of currently existing tools.

1.3 Geophysical instruments [Module 6]

Geodetic VLBI: Geodetic VLBI observing uses both the 20 m and OTT telescopes. Observations with the Onsala 20 m telescope use its S/X frequency band receiver system, are 24 h long and form part of the regular IVS sessions in the R1-, RD-, RDV-, T2- and EUR- series. In total 45 sessions in the IVS program were observed during 2019. 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 25 international broadband VGOS test (VT) sessions of 24 h duration each, 17 European broadband VGOS (EV) sessions of 4–6 h duration each, and 3 VGOS-B (VB) sessions of 1 h duration. During all these sessions both the OE and OW stations 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 6 VGOS partner stations, the EV-sessions were observed primarily with two other European partner stations, i.e. Yebes and Wettzell. The VB- sessions involved Onsala and Ishioka in Japan; as station that also joined a a small number of EV-sessions in the end of 2019. The VT-sessions were correlated at the MIT/Haystack correlator, the EV-sessions at the Bonn correlator, and the VB-sessions will be correlated locally at Onsala using software correlation. The goal of the VB-sessions is to determine UT1- UTC in parallel with simultaneously observed IVS-Intensive sessions with legacy S/X systems.

GNSS stations: OSO’s primary GNSS station, called ONSA, was operated continuously during 2019. It is a station in the SWEPOS network operated by Lantmäteriet. It 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 (more details in Sect. 2.2). In addition to ONSA and ONS1, the 6 GNSS stations installed close to the Onsala twin telescopes were all running continuously during the year. Of special interest is the experimental station OTT5 which was equipped with antireflecting material in December 2018 in order to study the possible improvement from decreasing the impact of unwanted signal multipath propagation (see Fig. 1.1).

Figure 1.1. Some of the GNSS installations at OSO.

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 Onsala Fundamental Geodetic Station. The laboratory is furnished with platforms for visiting absolute gravimeters (AGs), which visit on average one to three times per year. The laboratory’s primary instrument is a superconducting gravimeter (SCG, model GWR 054). Within international networks 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 2019 OSG054 recorded data over 365 days. It missed 445 1-second data out of 31536000, which means 14 ppm of missing data. In 2019 there was one AG campaign from 6–9 August by Andreas Engfeld (Lantmäteriet). Service points to note are; – 2019-08-28: Coldhead change – 2019-09-05: Problem with Dewar pressure/heater control starting – 2019-10-05: Problem fixed. From November 21 to 26, the dewar was refilled in liquid Helium from 80 % to 95 %. The connector from the SG barometer to the central unit was destroyed during a storm on July 28 and was eventually replaced on October 14. Meanwhile, air pressure data from another barometer on site was used.

Tide gauges: The Onsala tide gauge station was running uninterrupted for the entire year, excluding the yearly cleaning of the well, causing a data gap of approximately 2 hours on the 20th 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 (RINEX) format and include multi-GNSS (i.e. GPS, GLONASS, Galielo, Beidou) code- and carrier-phase observations as well as signal-to-noise ratio (SNR) measurements.

Water Vapour Radiometers: Onsala’s two water vapour radiometers, Astrid and Konrad, measure the sky brightness temperatures at 21 GHz and 31 GHz from which the radio wave propagation delay in the atmosphere is inferred. This data can be used to improve the accuracy of geodetic VLBI observations. During 2019 Astrid and Konrad operated side by side in a continuous mode from the 1st of January to the 28th of July, when lightning from a thunder- storm damaged both instruments. Konrad was repaired and operated normally again from the 2nd of October to the end of the year.

Aeronomy station: The aeronomy station consists of two radiometers: 1) A 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 2019 the mirror pointing system of the H2O radiometer was rebuilt. This meant that the instrument could not be operated during the re-build phase, and thus there were only 114 days of collected H2O measurements. However, there were 346 days of collected CO/O3 measurements.

Seismometer station: OSO hosts a seismograph station in the Svenska nationella seismiska nätverket (SNSN) at 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. During 2019 disturbing signals were detected that are most likely due a crack that has developed in the concrete foundation of the seismometer.

Time and frequency laboratory: The time and frequency laboratory hosts a 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 also 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 6; that is for observations covering the period October 2018 – September 2019. 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 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 31 % of the Swedish users (individuals) were from other institutions than Chalmers. The Swedish non-Chalmers users were affiliated with Stockholm University, Uppsala University, and the Royal Swedish Academy of Sciences. About 28 % of the users in 2019 were women. There is no clear 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 2019 (see also the publication list at the end of this report). Conference publications are not included (except for conference papers by OSO staff on technical R&D). 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 Nordic ARC provides standard support for projects with Nordic PIs, and further dedicated support upon request. Accordingly, 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 and GMVA, 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 104/65, Nordic ARC node dedicated support 19/16 (Nordic/Swedish) • APEX 65/12 (total/Swedish) • Astronomical VLBI 35/15 (total/Swedish) • LOFAR 74/11 (total/Swedish) • 20 m telescope, single-dish 4/1 (total/Swedish) • Technical publ. by OSO staff 6

In addition, in 2019 there was 1 publication using astronomical data from the satellite Odin (now operating mainly in aeronomy mode), and 6 publications using data from the Swedish- ESO Submillimetre Telescope SEST (closed in 2003).

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 2019, there were proposals for 14 projects, out of which 13 were observed. There were 21 female and 28 male users on the observed projects. Of these, 8 were Swedish (all from Chalmers).

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 to acquire detailed insight of 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 in global databases such as station positions, Earth orientation/rotation rate and gravity field are 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 17 papers with one or more Swedish authors and 32 papers with non- Swedish authors published during 2019 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.

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 45 experiments, each one with a length of 24 h and rather evenly spread over the year, were carried out during 2019 with the Onsala 20 m telescope. Additionally, we have been observing with the Onsala twin telescopes during several VGOS sessions, both international (25 sessions, 24 h each) and European (17 sessions, 4–6 h each) ones, plus 3 one-baseline intensive sessions (1 h long). 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 within 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 these 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 captured using six stations around the Onsala twin telescopes, called OTT1 to OTT6 whose data are then stored at Lantmäteriet. It shall be noted that the motivation for using GNSS data from OSO is that these stations are co-located with one of the most accurately determined VLBI stations world-wide. Therefore, indirectly the OSO VLBI data also contributes to OSO GNSS data quality. Many of the ultimate users of this data are found in the geophysical research community where GNSS data typically 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 such as e.g, plate tectonics, crustal deformation, space weather, sea level, climate, meteorological monitoring, et cetera. During 2019 the GNSS station OSOI has in addition been operated and has contributed to ESA’s ionospheric monitoring network. OSO provides, via contributions to the above database, access for the national and international user communities to robust international reference frame and other geoscience data.

Gravimeter Laboratory: Gravimeter data with one-second samples and maximum with a two-minutes latency are publically 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 (Germany), on a monthly schedule. 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 2019 one visit with an absolute gravimeter, Lantmäteriet's FG5, took place.

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). Loading-induced displacements are computed from a range of global ocean tide maps, using 28 sources featuring 8 to 11 tide species each. This service, endorsed by the IERS, has as its main purpose to provide consistent reduction of ocean tide loading effects to VLBI, GNSS and SLR analysis centres in their preparation of products that maintain the International Terestrial Reference Frame (ITRF). Apart from this, the service’s logbook hints at a large number of users peripheral or outside the ITRF community making use of the OSO ocean loading computing service in their analysis of GNSS observations.

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 2019 OSO collected about 114 days of atmospheric 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 2019 OSO has collected 346 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]

As described in the annual publication list there have been many ALMA results published in 2019 making use of OSO ARC node support; below details are given of two of the highest significance such results led by Swedish authors. Another ALMA related scientific highlight involving OSO staff contributions concerns ALMA’s participation in the Event Horizon Telescope observations of M87’s black hole (see Sect. 3.3).

Stringent limits on the magnetic field strength in the disc of TW Hya

W. H. T. Vlemmings, B. Lankhaar, P. Cazzoletti, C. Ceccobello, D. Dall’Olio, E. F. van Dishoeck, S. Facchini, E. M. L. Humphreys, M. V. Persson, L. Testi, and J. P. Williams. Astronomy & Astrophysics, 624, L7 (2019)

Summary: Magnetic fields likely play an important role during the evolution of planet forming disks. But only very limited information exists on the magnetic field strength in such disks. So far, most observations have relied on dust polarization, but unfortunately recent observations have shown that dust self-scattering at (sub-)millimeter wavelengths significantly complicates the dust observation interpretation. This leaves direct magnetic field measurements using the Zeeman effect of the CN radical as one of the most promising ways to determine the magnetic field strength. Vlemmings et al. (2019) used some of the first ALMA Zeeman observations to provide the so-far most stringent limit on the vertical magnetic field component of the proto-planetary disk around the T Tauri star TW Hya. Stacking a number of CN hyperfine components, a limit of |Bz|<0.8 mG was reached (see Fig. 3.1). This limit rules out several disk models and provides the first constraints to be compared with magneto-hydrodynamic simulations.

Figure 3.1. (left) An integrated intensity map of one of the CN hyperfine components in the disk around TW Hya. The dashed line is the line of nodes and the cross indicates the peak of the CN emission. (right) The stacked CN total intensity and circular polarization spectrum after azimuthal averaging. The red line indicates a model for magnetic field strength of 0.8 mG.

Kinematics around the B335 protostar down to AU scales

P. Bjerkeli, J. P. Ramsey, D. Harsono, H. Calcutt, L. E. Kristensen, M. H. D. van der Wiel, J. K. Jørgensen, S. Muller, and M. V. Persson. Astronomy & Astrophysics, 631, A64 (2019)

Summary: The kinematics and morphological properties of the region around the protostar B335 are studied in great detail by combining multiple ALMA data sets of different angular resolutions. B335 is perhaps one of the youngest known protostars and does not yet show evidence of a rotationally supported accretion disk. To investigate the relationship between outflow launching and formation of any disk-like structure, a wide range of spatial scales need to be covered. With dedicated support from the Nordic ARC node in Onsala, Bjerkeli et al. (2019) managed to produce a high-fidelity 12CO image, covering an impressive range of structures scaling from 3 au (0.03”) to 700 au (7”). The image was produced by combining data acquired between 2013 and 2017 and reveals unprecedented details of the environment of B335 (see Fig. 3.2).

Figure 3.2. Moment 0 map of the 12CO emission (colour contours), overlaid on the continuum (grayscale) in the combined dataset (excerpt from Bjerkeli et al., 2019; their Fig. 5). The emission is -1 -1 integrated from 2.0 to 6.0 km s with respect to the source velocity, 8.3 km s w.r.t. vLSR. Selected mean spectra, averaged over circular regions of 10 au radius, are indicated by the coloured points and the corresponding coloured spectral line profiles.

The X-shaped outflow shows no signs of rotation at distances larger than 30 au from the protostar, which suggests that most of the 12CO emitting gas originates at the edge of the surrounding envelope. Since most of the outflow emission is recovered, the combined data cube reveals the scales over which entrainment takes place. Within ~10 au of the protostar, a clear rotation signature is observed in CH3OH and one 12 line of SO2. Using high-velocity CO features in the vicinity of the protostar, the launching radius is estimated to be less than 0.1 au from the centre of the continuum peak source, but no rotationally-supported disk can be seen.

3.2 APEX [Module 3]

HD 101584: Circumstellar characteristics and evolutionary status

H. Olofsson, T. Khouri, M. Maercker, P. Bergman, L. Doan, D. Tafoya, W.H.T. Vlemmings, E.M.L. Humphreys, M. Lindqvist, L. Nyman, S. Ramstedt. Astronomy & Astrophysics 623, 153 (2019)

Summary: ALMA and APEX synergetic observations of the binary stellar object HD 101584. The APEX telescope was used to observe some 20 targeted spectral lines using several different heterodyne receivers. One example of such a line is visualised in Fig. 3.3, where the complicated nature of HD 101584 is revealed by the complex line profile extending over some 300 km/s. The existence of the rather complex species H2CO and CH3OH indicates that shocks, possibly paired with dust grains, may be responsible for the observed abundances of these molecules.

Figure 3.3. The 13CO(2-1) spectral line near 220 GHz as observed towards HD 101584 with APEX and ALMA (as averaged over the primary beam). Most of the observed flux is captured by ALMA, especially at the extreme velocities and in the central peak. For the broad feature between -20 km/s and 100 km/s only about 40% of the flux is recovered with ALMA as indicated by the single-dish APEX observations.

Weak-lensing mass calibration of the Sunyaev-Zel'dovich effect using APEX-SZ galaxy clusters

A. Nagarajan, F. Pacaud, M. Sommer, M. Klein, K. Basu, F. Bertoldi, A. T. Lee, P. A. R. Ade, A. N. Bender, D. Ferrusca, N. W. Halverson, C. Horellou, B. R. Johnson, J. Kennedy, R. Kneissl, K. M. Menten, C. L. Reichardt, C. Tucker, B. Westbrook. Monthly Notices of the Royal Astronomical Society 488, 1728 (2019)

Summary: The APEX visitor instrument APEX-SZ, a bolometer array working at 150 GHz with a 23 arcminutes field of view, was designed to study the SZ effect. Here the authors observed 39 galaxy clusters to provide for an accurate mass calibration of the integrated Compton- ionization. Reliable mass estimates of galaxy clusters are crucial for their use as cosmological probes.

3.3 Astronomical VLBI [Module 4]

First Image of a Black Hole

The Event Horizon Telescope Collaboration (from Sweden, J. Conway, M. Lindqvist, I. Marti-Vidal). Astrophysical Journal Letters 875, Paper I-VI (2019)

Summary: On 10th April 2019, the Event Horizon Telescope (EHT) collaboration, a global VLBI array operating at a wavelength of 1.3 mm, presented its first results - an image of the shadow of the supermassive black hole in galaxy M87, see Fig. 3.4. The EHT collaboration involves more than 200 scientists and engineers from 19 countries. The published image is dominated by a ring structure of 42 ± 3 μas diameter that is brighter in the south. The brightness excess is explained as relativistic beaming of material rotating around the black hole, with gas to the South approaching the observer. The structure has a central brightness depression with a contrast of >10:1, which matches the expected signature of the black hole shadow. The observations give an estimated black hole mass of M = 6.5 ± 0.7 × 109 M .

Further details can be found in a series of six papers in a special⊙ issue of The Astrophysical Journal Letters. The telescopes contributing to this result were ALMA (Chile), APEX (Chile), the IRAM 30 m telescope (Spain), the James Clerk Maxwell Telescope (Hawaii), the Submillimeter Array (Hawaii, USA), the Large Millimeter Telescope Alfonso Serrano (Mexico), and the Submillimeter Telescope (Arizona, USA). OSO contributed to the M87 EHT result both via telescope infrastructure, as one of the three partners to APEX, and via other specific contributions. The latter include sending observers to APEX to develop and test operational VLBI and developing critical software for the EHT. These software contributions included an algorithm and code developed by the OSO Nordic ARC node member Ivan Marti-Vidal to allow for the combination of ALMA data (which observes with linear polarization) with the other telescopes in the EHT (observing with circular polarization). Ivan Marti-Vidal also made important contributions to the software needed to internally calibrate the phased-up ALMA for inclusion in the EHT VLBI array.

Figure 3.4. EHT images of M87 on four different observing nights in 2017. The indicated resolving beam shown bottom right is 20 μas in diameter. From the EHT collaboration (2019, Paper IV).

Compact radio emission indicates a structured jet produced by a binary neutron star merger in gravitational wave source GW170817

G. Ghirlanda, O. S. Salafia, Z. Paragi, M. Giroletti, J. Yang, B. Marcote, J. Blanchard, I. Agudo, T. An, M. G. Bernardini, R. Beswick, M. Branchesi, S. Campana, C. Casadio, E. Chassande- Mottin, M. Colpi, S. Covino, P. D’Avanzo, V. D’Elia, S. Frey, M. Gawronski, G. Ghisellini, L. I. Gurvits, P. G. Jonker, H. J. van Langevelde, A. Melandri, J. Moldon, L. Nava, A. Perego, M. A. Perez-Torres, C. Reynolds, R. Salvaterra, G. Tagliaferri, T. Venturi, S. D. Vergani, M. Zhang. Science, Volume 363, Issue 6430, 968 (2019)

Summary: The binary neutron star merger event GW170817 was the first source detected through both gravitational waves and electromagnetic radiation. The early optical observations located its host galaxy as NGC 4993 and found temporal and spectral properties consistent with a source powered by the radioactive decay of material ejected during and after the merger. Later afterglow emission detected at radio wavelengths is theorised to have been produced by either a narrow relativistic jet or an isotropic outflow interacting with surrounding material. Ghirlanda et al. (2019) presented imaging results from global VLBI observations using 32 radio telescopes including the Onsala 25 m radio telescope. The apparent source size, 207 days after the merger, is constrained to be smaller than 2.5 milli-arc seconds at the 90 % confidence level. This compact structure indicates that GW170817 produced a structured relativistic jet instead of an isotropic outflow which would have produced a larger apparent size, Fig. 3.5.

Figure 3.5. The global VLBI imaging and simulation results of GW170817. The inset shows real and simulated pseudo-colour images (top), obtained in observations as well as based on model image distributions (bottom) for various scenarios (collimated jet, jet-cocoon with different opening angles). The background artist's impression represents the jet braking through the dense gas ejecta, which was produced during the merger of neutron stars that caused the gravitational waves recorded as GW170817.

A radio structure resolved at the deca-parsec scale in the radio-quiet quasar PDS 456 with an extremely powerful X-ray outflow

J. Yang, T. An, F. Zheng, W.A. Baan, Z. Paragi, P. Mohan, Z. Zhang, X. Liu. Monthly Notices of the Royal Astronomical Society 482, 1701 (2019)

Summary: Rapidly accreting active galactic nuclei (AGN) might host radiatively driven mildly relativistic outflows. Some of these powerful X-ray absorbing wide-aperture outflows are expected to produce strong internal shocks resulting in a significant non-thermal emission. The radio-quiet quasar PDS 456 has a bolometric luminosity reaching the accretion Eddington limit and a relativistic X-ray outflow with a kinetic power high enough to quench the star formation in its host galaxy. To search for the outflow-driven radio emission in PDS 456, an international group led by Yang performed very-long-baseline interferometric (VLBI) observations of the quasar with the European VLBI Network (EVN) including the Onsala 25 m radio telescope. The EVN imaging results are displayed in Fig. 3.6. These images show two faint radio components with a projected separation of about 20 pc in the nuclear region. The high- resolution VLBI structure at the deca-pc scale can be explained as either a poorly collimated young jet or a bidirectional radio-emitting outflow, launched in the vicinity of a strongly accreting central engine.

Figure 3.6. The EVN 5GHz image of the optically bright and radio-quiet quasar PDS 456. There are two faint radio components C1 and C2, found in the nuclear region. The black cross marks the optical centroid of the GAIA observations.

The population of SNe/SNRs in the starburst galaxy Arp 220. A self-consistent analysis of 20 years of VLBI monitoring

E. Varenius, J. E. Conway, F. Batejat, I. Martí-Vidal, M. A. Pérez-Torres, S. Aalto, A. Alberdi, C. J. Lonsdale and P. Diamond. Astronomy & Astrophysics 623, A173 (2019)

Summary: The nearby (77 Mpc) starburst galaxy Arp 220 is an excellent laboratory for studies of extreme astrophysical environments. For 20 years, Very Long Baseline Interferometry (VLBI) has been used to monitor a population of compact sources in Arp 220. In this study,

Varenius et al. (2019) detect 97 sources (see Fig 3.7), thought to be supernovae (SNe) and supernova remnants (SNRs). SNe and SNRs are thought to be the sites of relativistic particle acceleration powering star formation induced radio emission in galaxies. Understanding the origin of the radio emission from starburst galaxies is important for e.g. for interpreting future SKA surveys of the early universe. Varenius et al. (2019) find a relation between source luminosity and size within Arp 220, with larger sources being less luminous. This is consistent with the starburst in Arp 220 being a more extreme version of those seen other galaxies such as M82. They also find a source luminosity function similar to SNRs in normal galaxies. The similarity is notable because the environment in Arp 220 is extreme compared to normal galaxies. Finally, they find that about 80 % of the total radio emission from Arp 220 cannot be explained simply as the sum of the compact sources. Colliding SNR shocks and/or additional secondary electron production in the ISM could possibly explain the additional flux. Future VLBI observations of Arp 220 are needed to further constrain the population of weaker sources, and hopefully reveal the origin of all the radio emission.

Figure 3.7. A zoom on the central part of the 6cm VLBI image of the western nucleus in Arp 220 (Varenius et al. 2019). The bright dots are SNe and SNRs. Resolving these sources to measure their size is only possible with the very fine angular resolution provide by global VLBI.

3.4 LOFAR [Module 5]

2019 was a major year for LOFAR. In February 25 articles were published in a special issue of Astronomy & Astrophysics in connection to the LOFAR Sky Survey’s first Data Release (DR1) of about 2 % (424 square degrees) of the northern sky. This first part of the LOFAR Two-Meter Sky Survey (LoTSS; Shimwell et al. 2019) covers the so-called HETDEX region, in which more than 325 000 radio sources (most of them Active Galactic Nuclei, AGN) were identified and characterized. The sensitivity of LoTSS is such that the number density of detected sources is about 10 times higher than in previous wide-area radio surveys. C. Horellou (Chalmers) was involved in a number of studies based on LoTSS DR1 data (on galaxy groups, Nikiel-

Wroczynski et al. 2019; and on nearby star-forming galaxies, Heesen et al. 2019a, Heesen et al. 2019b, Miskolczi et al. 2019). This work was led by the LOFAR Magnetism Key Science Project (the MKSP, a consortium of about 100 researchers, of which C. Horellou is co-PI), in collaboration with the Surveys KSP. Another important work was the detection of polarization in a giant radio galaxy and the use of the Faraday Rotation Measures (RM) to place constraints on the intergalactic magnetic field (O'Sullivan et al. 2019). Other LOFAR work included a detailed analysis of AGN in a galaxy cluster (Clarke et al. 2019) and the discovery of a bridge of radio emission between two massive clusters of galaxies (Govoni et al. 2019, see below and Fig 3.8). As members of the Surveys KSP Chalmers scientists (J. Conway, C. Horellou) also have early access to data that will be included in the second data release (DR2; to occur in 2021) that will cover about 27% of the northern sky). Construction of a LOFAR Magnetism Rotation Measure (RM) grid is ongoing (O'Sullivan et al., in prep); this will be a major resource of background sources to probe foreground cosmic magnetic fields because of the high RM precision achievable by LOFAR (better than 1 rad/m2, which is about 100 times better than what has been achieved so far at GHz frequencies). A new PhD student, Sara Piras, was hired at Chalmers in September 2019 to work on LOFAR polarization. A large LOFAR magnestism related conference was held in the Netherlands in June 2019 (C. Horellou was a member of the Scientific Organizing Committee) and a LOFAR Surveys internal meeting was held in Italy in December. Conway and Horellou participated in both meetings. Horellou also participated and helped organize the annual meeting of the LOFAR Magnetism KSP in Germany in September. Below are given details of the summary paper (Shimwell) related to the DR1 ‘paper splash’ and of the detection with LOFAR of radio emsision from a filament of the cosmic web connecting two galaxy clusters.

The LOFAR Two-metre Sky Survey II. First data release

T. W. Shimwell., …, J. E. Conway, …, S. Bourke, …, C. Horellou, …, E. Varenius, et al. Astronomy & Astrophysics 622, A1 (2019)

Summary: Published article to accompany the first data release of the LOFAR Two-metre Sky Survey (LoTSS). LoTSS is the most extensive astronomical survey to date of the sky in the 2 meter wavelength band. It contains more than 300 thousand sources over 424 square degrees and has achieved a sensitivity of better 100 µJy per beam. This survey will be of great legacy value to the astronomical community. The release has created media attention both at the time of its release and through the LOFAR Radio Galaxy Zoo (RGZ) project. The RGZ is a citizen science initiative to get interested citizens to help astronomers identify radio galaxies.

A radio ridge connecting two galaxy clusters in a filament of the cosmic web

F. Govoni, E. Orrù, A. Bonafede, M. Iacobelli, R. Paladino, F. Vazza, M. Murgia,V. Vacca, G. Giovannini, L. Feretti, F. Loi, G. Bernardi, C. Ferrari, R.F. Pizzo, C. Gheller, S. Manti, M. Brüggen, G. Brunetti, R. Cassan, F. de Gasperin, T.A. Enßlin, M. Hoeft, C. Horellou, H. Junklewitz, H.J.A. Röttgering, A.M.M. Scaife, T.W. Shimwell, R.J. van Weeren, M. Wise. Science 364, 981 (2019)

Summary: Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intra-cluster gas. A ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 was observed with the Low-Frequency Array (LOFAR)

telescope network at 140 MHz (see Fig 3.8). This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. Simulations were performed to show that a volume-filling distribution of weak shocks may reaccelerate a pre-existing population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.

Figure 3.8. LOFAR image of the 1.4°×1.4° region centered on the Abell 0399 - Abell 0401 system (Govoni et al. 2019) showing the bridge in radio emission between the two clusters. Colour and contours show the radio emission at 140 MHz with a resolution of 80′′ and rms sensitivity of 1 mJy beam−1. The beam size and shape is indicated by the inset at the bottom left. Contour levels start at 3 mJy beam−1 and increase by factors of 2. One negative contour (red) is drawn at –3 mJy beam−1. The black cross (right ascension 02h 59m 38s declination +13° 54′ 55′′, J2000 equinox) indicates the location of a strong radio source that was removed from the image.

3.5 Onsala 20 m telescope single dish

Observational Signatures of End-dominated Collapse in the S242 Filamentary Structure

L.K. Dewangan, L.E. Pirogov, O.L. Ryabukhina, D. K. Ojha, I. Zinchenko. Astrophysical Journal 877, 1 (2019)

Summary: The sideband separating capability of the 3 mm receiver was used to simultaneously observe the important ground state carbon monoxide isotopologue lines near 110 GHz, as well as the carbon sulphide 2-1 line near 98 GHz, over large spatial scales covering a filament in the S235 star forming region, see Fig. 3.9. The comprehensive analysis this enabled showed that the S242 filament is a very good example of so-called end-dominated collapse.

Figure 3.9. Integrated intensity maps for 13CO(1-0), C18O(1-0), and CS(2-1), resp., in S242.

Detection of Class I Methanol Masers in some IRDCs at 44 GHz with 20-m Onsala Radio Telescope

N.N. Shakhvorostova, A.V. Alakoz, A.O.H. Olofsson et al. URSI GASS 2020 (abstract for conference presentation at XXXIII General Assembly and Scientific Symposium of the International Union of Radio Science URSI)

Summary: A number of new class I methanol maser sources were detected near 44 GHz in a survey of infrared dark clouds carried out in 2019 with the Onsala 20 m telescope. The project also began* observing 3 mm band lines in these sources using the sideband separating feature to cover both the temperature diagnostic line of methyl acteylene at 85 GHz, and carbon sulphide and several thermal methanol lines near 97 GHz which will aid in estimating the density in the maser regions. The study of class I methanol masers can reveal the presence of shock waves in early stages of star formation. *Additional observations were granted and carried out through a DDT proposal in 2020 in order to finish the high frequency part of the project.

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.

Correcting surface loading at the observation level: impact on global GNSS and VLBI station networks.

B. Männel, H. Dobslaw, R. Dill, S. Glaser, K. Balidakis, M. Thomas, H. Schuh. Journal of Geodesy 93, 2003 (2019)

Summary: Time-dependent mass variations of the near-surface geophysical fluids in the atmosphere, oceans and the continental hydrosphere lead to systematic and significant load- induced deformations of the Earth’s crust. More than 10 years of observations from about 400 GNSS and 33 VLBI stations were specifically reprocessed to incorporate non-tidal loading correction models at the observation level. As a result, the coordinate repeatabilities and residual annual amplitudes decrease by up to 13 mm and 7 mm, respectively, when the loading models are applied. In addition, the standard deviation of the daily estimated vertical coordinate is reduced by up to 6.8 mm. Furthermore, the VLBI-based EOP estimates are critically susceptible to surface loading effects, with root-mean-squared differences reaching of up to 0.2 mas for polar motion, and 10 μs for UT1-UTC.

Evidence of daily hydrological loading in GPS time series over Europe.

A. Springer, M. A. Karegar, J. Kusche, J. Keune, W. Kurtz, S. Kollet. Journal of Geodesy 93, 2145 (2019)

Summary: Loading deformations from atmospheric, oceanic, and hydrological mass changes mask geophysical processes such as land subsidence and tectonic or volcanic deformation. While it is known that hydrological loading plays a role at seasonal time scales, the authors demonstrate in this publication evidence that also fast water storage changes contribute to daily Global Positioning System (GPS) height time series. Accounting for daily hydrological mass changes based on a high-resolution hydrological model based on GRACE data reduces the root mean square scatter of GPS height time series almost by a factor of two when compared to monthly hydrological mass changes.

The Potential for Unifying Global‐Scale Satellite Measurements of Ground Displacements using Radio Telescopes.

A. L. Parker, L. McCallum, W. E. Featherstone, J. McCallum, R. Haas. Geophysical Research Letters 46(21), 11841 (2019)

Summary: The expansion of globally consistent satellite-radar imagery presents new opportunities to measure Earth-surface displacements on inter-continental scales. Global applications, including a complete assessment of the land contribution to relative sea-level rise, first demand new solutions to unify relative satellite-radar observations in a geocentric reference frame. The international network of Very Long Baseline Interferometry telescopes provides an existing, yet unexploited, link to unify satellite-radar measurements on a global scale. Proof-of-concept experiments reveal the suitability of these instruments as high

amplitude reflectors for satellite-radar and thus provide direct connections to a globally consistent reference frame. Automated tracking of radar satellites is easily integrated into telescope operations alongside ongoing schedules for geodesy and astrometry. Utilizing existing telescopes in this way completely avoids the need for additional geodetic infrastructure or ground surveys and is ready to implement immediately across the telescope network as a first step towards using satellite-radar on a global scale.

3.7 Device physics and Terahertz technology [Module 8]

The research and development work of OSO’s GARD group supports the development of future instrumentation for millimetre astronomy (for example future ALMA receiver upgrades). Example of this work are given below.

Specific capacitance of Nb/Al-AlN/Nb superconducting tunnel junctions

A. Pavolotsky, C. D. López, I. Vrethed Tidekrans, D. Meledin, V. Desmaris, V. Belitsky. Proceedings 30th International Symposium on Space THz Technology (ISSTT2019), Gothenburg, Sweden, April 15-17, 2019

Summary: Modern radio astronomy demands broadband receiver systems. For SIS mixers, this translates into objective to employ superconducting tunnel junctions with a very low RnA and low specific capacitance. The traditionally used Nb/AlOx/Nb junctions have largely approached their physical limit of minimizing those parameters. It is commonly recognized, that it is AlN-barrier junctions, which are needed for further progressing broadband SIS mixer instrumentation for radio astronomy. In this work, we present the progress in fabrication of high quality Nb/Al-AlN/Nb superconducting tunnel (SIS) junctions and their characterization in terms of their DC electric properties and specific capacitance (see Fig. 3.10). GARD has developed new technology to fabricate such SIS junctions. The specific capacitance of the studied Nb/Al-AlN/Nb junctions is noticeably lower than that reported for the Nb/AlOx/Nb junctions. These new junctions will be used in new broadband SIS mixers for short mm-waves and terahertz frequencies.

Figure 3.10. Examples of Nb/Al-AlN/Nb junctions’ current voltage characteristics with RnA ranging 2 between 3 and 120 Ωµm . The legend inside each plot panel shows junctions’s size, RnA and Rj/Rn values.

See also Sect. 4.2 for another highlight from the Group for Advanced Receiver development (GARD) concerning receiver development for APEX.

4 Instrument upgrades and technical R&D

4.1 ALMA [Modules 2 & 8]

The ALMA Observatory released in 2018 its development roadmap towards 2030 (https://www.almaobservatory.org/en/publications/the-alma-development-roadmap/), describing the vision and development of ALMA new capabilities for the coming decade. One specific project within that time frame, related to building a new correlator, was halted in 2019; currently alternative designs are currently being explored for this correlator. On the receiver side Band 1 development (led by East Asia) progressed during 2019 with these receivers planned for deployment in 2020. Band 2 receivers (lead by Europe) were approved for prototyping and pre-production. Resources have also been devoted to the project of re-imaging Cycle 2-4 observations (ARI-L) to expand the products available in the ALMA Science Archive. As part of preparation for ALMA Band 2 deployment, GARD was involved in studies on the feasibility of such a receiver covering 67–116 GHz (ALMA Band 2+3) with an IF band of 4–12 GHz. As part of these studies, GARD designed a prototype cold cartridge, which was used to evaluate optics, amplifiers, orthomode transducer and overall cold cartridge layout. The 23

results of this successful project; a large collaboration between 16 institutes, was presented in Yagoubov, Mroczkowski1, Belitsky et al., Astronomy & Astrophysics 634, A46 (2020): The collaboration resulted in the design, fabrication, and testing of multiple technical solutions for each of the receiver components, allowing a state-of-the-art receiver covering the full combined ALMA Band 2 and 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years and it is capable of dual-polarization, sideband-separating observations in intermediate frequency bands spanning 4−18 GHz for a total of 28 GHz on-sky bandwidth per polarization channel. In conclusion, the 67−116 GHz wideband implementation for ALMA Band 2 is now feasible and the receiver provides a compelling instrumental upgrade for ALMA that will enhance its observational capabilities and scientific impact. In other applied research supporting ALMA improvements Onsala Space Observatory has continued its involvement in the EU project RadioNet Joint Research Actovity RINGS, in particular on full polarization and beam modelling for polarization calibration with ALMA (and LOFAR). Members of the ALMA Nordic ARC node at Onsala hves also provided advice for the ALMA Development Study “High-Cadence Imaging of the Sun” (PI: S. Wedemeyer).

4.2 APEX [Modules 3 and 8]

During the 2019 APEX summer shutdown (January to March) several hardware upgrades were performed. First, a new subreflector was installed in mid-January as the previous one did not meet required surface accuracy specifications. Secondly, VERTEX, the antenna manufacturer, replaced several of the panels and modified panel adjusters of the some of the panels to allow a higher surface accuracy. Subsequent holography measurements demonstrated a rms surface accuracy of about 11-12 micrometres. Some panels were left untouched and this work is expected to be fully completed in 2020 when the goal of 10 micrometres overall surface accuracy will hopefully be achieved. Thirdly, the intermediate frequency (IF) system was expanded from 4−8 GHz to 4−12 GHz, therefore increasing the instantaneous bandwidth by a factor of two. As a result, spectral scan type observations of galactic and extragalactic sources can now be done much more efficiently. Together with the new IF system, new Fast Fourier Transform Spectrometers (FFTS) were also delivered to record the signal in the 4−12 GHz IF bands. Most heterodyne receivers can use this new enhanced IF system and also the calibration system can now, by default, make channel-wise calibration to allow for a more accurate intensity calibration at frequencies near telluric lines. During the APEX summer shutdown, OSOs receiver group at Chalmers, GARD, was at APEX to re-position the SEPIA (Swedish ESO PI receiver for APEX) cryostat from the APEX cabin-A visitor instrument position into the facility instrument position where it will be permanently installed. At the time of the position change the cryostat hosted the SEPIA180 (Band 5) and SEPIA660 (Band 9) cartridge receivers. The change of position made it necessary to completely redesign the tertiary optical system of the receivers (Lapkin et al. 2019, Proceedings 30th International Symposium on Space THz Technology, Gothenburg, Sweden, April 15−17, 2019). The SEPIA control software was also updated and enhanced during 2019. Most of the software additions relate to the coming SEPIA345 receiver to be installed at APEX in 2020. The SEPIA660 receiver (developed by NOVA in Netherlands) which was technically and scientifically commissioned in late 2018, was accepted by the APEX board as a facility receiver in 2019. Several of the SEPIA660 receiver characteristics were measured to be much better than what was stated in the original requirements. The receiver has been used scientifically during the 2019 observing season. Technically, the receiver has proven useful to determine the telescope beam shape by mapping the strong 658 GHz water maser line toward

oxygen-rich circumstellar envelopes. These high frequency observations provide an excellent complement to holography measurements to determine the antenna surface accuracy.

New Optics for SEPIA- Heterodyne Facility Instrument for the APEX Telescope

I. Lapkin, S.-E. Ferm, M. Fredrixon, D. Meledin, M. Strandberg, V. Desmaris, A. Ermakov, A. Pavolotsky, E. Sundin and V. Belitsky. Proceedings 30th International Symposium on Space THz Technology (ISSTT2019), Gothenburg, Sweden, April 15-17, 2019

Summary: GARD has designed, fabricated and installed all-new tertiary optics for the APEX SEPIA receiver (see Fig. 4.1). The new optics has allowed to place SEPIA receiver to the central position and release the visitor instrument position for new receivers. Moving SEPIA from its original PI into Facility Instrument position brought additional and severe space limitations constrained by the support structure, the facility calibration load unit and requirements for the optical path clearance for the PI instruments, located at the left and right sides of the facility instrument position. That had led to the necessity of the complete redesigning of the SEPIA tertiary optics. The new optics was designed and parts were manufactured in 2018 and SEPIA was installed onto its new position in February-March 2019 by GARD.

Beam from the antenna

NMF1

NMF3

Figure 4.1. Left: The 3D CAD model of the new layout of the SEPIA instrument at the Facility Instrument position. NMF1 – Switching mirror between PI and SEPIA instruments; NMA1 – active adjustable refocusing mirror, NMF4 – Channel switching mirror; NMA2-1, NMA2-2, NMA2-3 – Individual channel refocusing mirrors NMA2; (“ALMA Band 5”; “ALMA Band 7”; “ALMA Band 9”) – ALMA receiving cartridges. Right: SEPIA receiver installed in the central position;1 – Nasmyth flange, Cabin A; 2 – Instrument Selection Mirror (PI or Facility Instrument); 3 – SEPIA Active Top mirror support bracket; 4 – SEPIA New Optics; 5 – SEPIA Receiver.

4.3 Astronomical VLBI [Module 4]

The 25 m telescope IF-system was moved from the telescope cabin to the 20 m telescope control building. A modern set of equipment, with remote interfacing the two VLBI backends, including IF monitoring covering the existing VLBI IF band, and the newly implemented 4-8 GHz IF band on the 20 m antenna, has been installed. OSO was involved in successful 8 Gbps VLBI tests using the DBBC2 on the 20m telescope. OSO was also involved in the VLBI related H2020 project JUMPING JIVE (see Sect. 9). During 2019, 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 will be a document, in the form of a White Paper, that will address and explore several relevant points in setting the future priorities of VLBI science capabilities. WP8 addresses 2 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 (see Sect. 9) is developing a revolutionary decade frequency range (1.5–15.5 GHz) receiver for VLBI. OSO is leading the feed design for the first prototype which is optimised for the prime-focus geometry of the Effelsberg 100 m telescope. The feed has been sent to Effelsberg in Germany for integration in the receiver cryostat. On-sky tests will take place in 2020. The BRAND EVN partners include Germany (MPIfR), Italy (INAF), Sweden (OSO), Spain (IGN), The Netherlands (ASTRON), and Latvia (VIRAC). Algorithm and software development relevant to VLBI forms part of the Radio Interferometry Next Generation Software (RINGS) RadioNet project; this project is described in more detail in Sects. 4.4 and 9. Since May 2019 the Onsala 25 m telescope has teken 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. In total Onsala observed on 81 days for this project in 2019.

4.4 LOFAR [Module 5]

During 2019, Onsala Space Observatory was involved in the LOFAR For Space-Weather (LOFAR4SW) project. LOFAR4SW is an EU funded Horizon 2020 Work Programme. It consists of a design study that will look at how the radio telescope LOFAR, which has a Swedish station at Onsala, can be upgraded to become a space-weather observatory that runs continuously and independently of LOFAR’s radio astronomy operations. In particular OSO has been involved in studying the software requirements of LOFAR4SW. The goal is to define requirements on software in terms of control, monitoring, pipeline processing and archiving. The proecjt also investigates how LOFAR4SW can be become an event driven observatory, responding to solar events triggered by both external and internal real-time data sources. The LOFAR4SW effort will build on the LOFAR2.0 project that consists of upgrading LOFAR stations to allow for a second independent beam so that multiple, simultaneous science targets become possible. During 2019, OSO developed the prototype software called iLiSA (international LOFAR in Stand Alone mode), which can be found at https://github.com/2baOrNot2ba/iLiSA.

This software was part of the LOFAR4SW deliverables presented at the MidTerm Review (MTR) hosted at the European Research Council (ERC) in Brussels in 2019. The outcome was that the ERC was very positive towards the project. Onsala Space Observatory has continued its involvement in the RadioNet JRA RINGS (see Sect. 9). The main objective for RINGS is to deliver advanced calibration algorithms for the next generation of radio astronomy facilities, characterized by high sensitivity, high bandwidth and long baselines. During 2019, OSO has completed the work in WP7.2 which involved full polarization and beam modelling for polarization calibration with ALMA and LOFAR, including polarization conversion from linear to circular polarization products. Part of the results were published in Creaner & Carozzi (2019). In WP 7.5, OSO has focused with RINGS on developing robust self-calibration routines.

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

In 2019, the 20 m telescope was fully migrated to a new control system (Bifrost). While improvements of this software were (and still are) ongoing, the last missing large component was developed and implemented, namely a mapping function for raster-type observations. The new tool was designed with long autonomous observations in mind and it has some features that – to our knowledge – are unprecedented elsewhere. Large-scale raster mapping is hampered by i) varying observing conditions (such as telescope elevation and weather) that can lead to spatial artificial bias and locally insufficient signal-to-noise ratio, and ii) the complexity of conducting an observation such that the most important subregions are covered in order of priority. With the new mapping tool, a memory is kept for each observed position of the hitherto achieved (theoretical) noise level. The user can then ask the system to by itself continuously modify the observation order strategy to prioritise the currently noisiest parts (see Fig. 4.2). Regardless of at what time the observation is ended, the resulting data cube should end up with the most even noise distribution possible, i.e., there is no need for user supervision to check possible impacts of e.g. temporarily poor weather on the noise distribution. The mapping tool also offers a large selection of map point ordering schemes and map point placement flexibility so that maps can be tailor-made for the often complex source structure of molecular clouds.

Figure 4.2. The Bifrost graphical user interface for mapping.

4.6 Geoscience [Module 6]

No upgrades of the geoscience equipment took place during 2019.

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

As mentioned in the Sect. 3.7, GARD runs a project to develop the fabrication of a new type of superconducting tunnel junction, a superconductor-insulator-superconductor (SIS) using an AlN tunnel insulation barrier. SIS junctions are primarily used in SIS mixers for frequencies 86–1200 GHz and are the dominating technology for radio-astronomy instrumentation at these frequencies. Compared to currently used SIS junctions using AlxOy tunnel barriers AlN barrier- based junctions promise lower specific capacitance and the possibility to realize junctions with about 10 times higher current density. These two advantages give the potential to make broader band RF/IF-wise mixers that should satisfy the specifications of new generation instruments for, e.g., as part of the ALMA Observatory Enhancement project. Currently, GARD has established a process for the fabrication of AlN barrier-based SIS junctions in the Chalmers Clean Room Facility using dedicated equipment. Figure 4.3 below demonstrates the current voltage characteristic of such junctions showing excellent device quality with Rj/Rn ratio above 20 for a wide range of current densities.

Figure 4.3. Specific capacitance of Nb/Al-AlN/Nb junction (red) as compared with that of Nb/Al- AlOx/Nb junctions (blue). Measurements were performed at 4 K physical temperature.

The project includes establishing production with stable and predictable yield of the junctions and characterization of the Nb/AlN/Nb SIS junction specific capacitance. This project is co- funded by ESO through a ALMA Upgrade program and the EU H2020 RadioNet JRA AETHRA. Another big project completed during 2019 was design of the SEPIA Band 7 receiver cartridge, covering the sky frequency band 211–376 GHz. The design of the SEPIA receiver was driven by the idea of using ALMA receiver cartridges on the APEX telescope. However,

old ALMA receiver cartridges are specified to have 4–8 GHz IF band while for the new generation of APEX receivers this is doubled to 4-12 GHz IF. GARD designed an entirely new receiver cartridge which follows the ALMA guidelines but uses new original optics, feed, OMT and mixers with their IF system. The scope and limitation of this report does not allow detailed description of this extensive project. We present here only some pictures and results in the Figs. 4.4 and 4.5 below.

Mirror 2

Support bracket

Magnetic coil Pol0

Orthomode transducer

2SB SIS Mixer Pol1

Mirror 1

IF isolator LSB Pol1

IF isolator USB Pol1

DC harness

4 K PLATE

Fiberglass spacer

15 K PLATE

Fiberglass spacer

110 K PLATE

300 K PLATE

Figure 4.4. Annotated picture of the SEPIA Band 7 Cold Cartridge Assembly. RF frequency band 211–376 GHz, Dual polarization, sideband separation receiver. IF output 4x4–12 GHz.

Figure 4.5. SEPIA B7 receiver cartridge measured noise temperature for Polarization 0, LSB. The red line shows measured 2SB LSB noise temperature, the black line presents the lowest noise temperature measured in each respective LSB. Insignificant difference between the two lines (note the Y-scale) indicates that the averaged over IF band noise temperature is very close to the minimum achieved. The straight blue and sloped blue-with-crosses lines show the specification 85 K and 4 x hf/k quantum noise respectively.

Other activities and projects. Only brief information on other activities and projects is given taking into account constrains on the length of the activity report document. As part of H2020 RadioNet JRA AETHRA, GARD worked on the design of ultra-wideband SIS mixer. The purpose of the project is to probe the boundaries of the existing technologies and drive them to new limits. GARD was involved in the design and experimental testing of balanced cryogenic HEMT amplifiers; this work is performed in collaboration with Spanish group at Yebes with some promising results reported during the 30th International Symposium on Space THz Technology (ISSTT2019), Gothenburg, Sweden, April 15-17, 2019. Finally, GARD has worked on upgrading the computer control system for the dedicated sputter machine which is the main work-horse for fabrication the SIS junctions. The previous control system was based on ab obsolete computer running Windows 95 and needed replacement. This project had a strong technical aspect and was very complex requiring deep insight into processing details, vacuum technique, electronics and software. GARD successfully finished the sputter update in 2019 and commissioned it. This system is now fully functional and available for use by GARD and by other groups within the Chalmers Clean Room facility, MC2.

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 2021 with its completion expected by 2027. 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 (innaugurated 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. During July 2019 a greatly expanded headquarters building, with room to eventually house 150 staff, was inaugurated. 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 international infrastructures). An international convention to establish a new SKA Observatory international organisation to build and operate SKA received its first signatories during March 2019. It is planned that during 2020 a sufficient number of countries will have ratified the convention to allow the SKA Observatory to come into existence and take over the management of the SKA project from the SKAO company. In Sweden a proposal to VR for Sweden to provide the Swedish share of SKA1 construction and operations funding and join the new SKA Observatory international organization was submitted to VR in February 2019. In September 2019 VR gave provisional approval of this proposal subject to final confirmation on receiving part of the construction funding from other financiers. In late 2019 a dialogue began between VR and OSO on defining a new contract to come into force during 2020 to replace the current OSO contract; with this new contract financing both the radio astronomy activities at OSO and the future Swedish annual contributions to SKA.

5.2 Completion of OSO contributions to SKA1-mid Design.

Since 2014 OSO has been involved in three work packages within the design phase of SKA1. OSO has designed the feed and LNA package for SKA1-mid Band 1 within the SKA Dish Consortium. During 2019 the final issues related to the delivery of this Band 1 design were completed, while Band 1 prototype constructed at OSO continued its testing on a MeerKAT antenna in South Africa. OSO was also till the end of 2018 the consortium leader for the Wide Band Single Pixel Feed (WSPF) Advanced Instrumentation Program (AIP). During 2019 the WBSPF consortium has been renewed and expanded into the Advanced Single Pixel Feed and Receiver (ASPFR) consortium (see below). OSO is also a member of the Phased Array Feed (PAF) Advanced Instrumentation Programme and during the year delivered components to support Swedish Low Noise Amplifiers as part of PAF prototypes.

5.3 Discussion on Swedish industrial contributions to SKA1 constructions.

During the year there were extensive discussions between SKA partner countries 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 SKA project has now defined Sweden as the ‘Level 1’ lead for two work packages, namely for the SKA1-mid Band 1 receiver and for SKA1-mid Digitizers. In addition, a Swedish company 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. During the latter months of the year CIT had initial talks with several Swedish companies that have capability to act as lead contractors to supply SKA1-mid band receivers and Digitizers. Within both these Level 1 work packages Sweden also began discussions with other countries who may supply Level 2 products.

5.4 Advanced Single Pixel Feed and Receivers (ASPFR) and SKA High Frequency Science Case

It is planned for SKA Observatory to have from the start of construction (2021) an Observatory Development Programme (ODP) – from which SKA Observatory central funding will be available to fund studies and development efforts. 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). The current self-funded SKA Advanced Instrumentation Programmes (AIPs) form a bridge to the ODP. Currently active AIPSs include one on Phased Array Feeds (PAFs of which OSO is a member) and one on dense Aperture Arrays. The Wide Band Single Pixel Feed (WBSPF) AIP led by OSO completed its work in 2018 but was reformed during 2019 with broadened scope as the Advanced Single Pixel Feed and Receiver (ASPFR) AIP. ASPFR covers work to develop all future single pixel receivers on SKA whether wide-band or conventional octave band receivers. The ASPFR includes in its scope the final design of receivers that are within the SKA1-mid architecture (such as Bands 3 and 4) but are not in the initial deployment as well as possible receivers (Band 6) which are at frequencies greater than the current receiver upper limit of 15 GHz on SKA1-mid. ASPFR also involves the development of critical supporting technology (such as cooling and digital sampling) needed for future single pixel feed receivers. During 2018 a project manager of ASPFR (Gary Hovey) was hired and began work at OSO in early 2019. Initial actions were to set up a scope of work and wiki page and recruit new member institutes and companies (in addition to those previously involved in the WBSPF). A well-attended face-to-face meeting at Chalmers campus was organized in September, at which a wide range of radio astronomy receiver technology relevant for future SKA enhancements was presented and discussed.

5.5 SKA Regional Centre planning and AENEAS

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 2019 a new body, the SRC Steering Committee (SRCSC), was set up to plan in detail the worldwide SRC network. Sweden is represented on this SRCSC by John Conway, who during 2019 attended SRCSC face-to-face meetings at SKA Headquarters in the UK in May and at the SKA

engineering meeting in Shanghai in November. During the past year the SRCSC began a white paper planning the organisation and scope of the SRC network. An important input to the international SRC design process was work completed during the year within the AENEAS EU Horizon 2020 project. This project has had the goal a model for European SRC provision. The three-year project concluded at the end of 2019 with the delivery to the EU of a number of reports describing both the technical design and possible organisation of a coordinated European SRC contribution. OSO contributed significantly in the AENEAS Work packages related to data transfer and computing. A number of OSO personnel attended AENEAS face-to-face meetings during the year – including the final summary meeting of the project in Utrecht, Netherlands in November.

6 Computers and networks [Module 10]

During 2019 the local Onsala computer cluster was upgraded to five machines with a total of 112 cores and 223 TB of data storage. The OSO owned cluster at the SNIC–C3SE node at Chalmers consists of 5 machines with a total of 160 cores with a 100 TB Lustre file-disk system plus 196 TB of slower disk storage (SNIC: Swedish National Infrastructure for Computing; C3SE: Chalmers Centre for Computational Science and Engineering). This storage is dimensioned to allow an international LOFAR data set (40 TB) plus two large ALMA data sets (20 TB) to be processed (including scratch space) on the Lustre file system. A set of data storage systems in Onsala used operationally for the temporary storage of raw VLBI data consists of four machines with a total capacity of 1.0 PB and 48 cores. 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 and astronomical VLBI data. There is also an option to transmit data in IP format, used for sending data to other stations/correlators.

7 Frequency protection [Module 10]

The radio spectrum is a limited resource which is under ever increasing pressure for frequency allocations from active (i.e., emitting) users. On behalf of European radio astronomers, the Committee on Radio Astronomy Frequencies (CRAF, 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 (Michael Lindqvist) 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 most of 2019 CRAF carried out preparatory work in advance of the World Radiocommunication Conference 2019 (WRC-19, held in November), a global conference held under the auspices of the International Telecommunication Union, ITU. The main outcome of these meetings are a set of new Radio Regulations which are international agreements that are

binding to ITU member states. The Radio Regulations define frequency allocations and the technical and regulatory conditions for use of the radio spectrum by a given service. The WRC-19 conference was held in Sharm El-Sheikh, Egypt for four weeks from 28th October to 22nd November 2019. It was attended by a record number of more than 3500 participants from more than 190 ITU member states, in addition to sector members representing major telecommunication companies and scientific organizations. CRAF, as an ITU sector member, represents the European radio astronomy observatories via the attendance of the CRAF chairman from OSO and the Frequency Manager, Fig. 7.1. CRAF teamed up with other radio astronomy groups and sector members at the conference such as IUCAF and SKAO to align the voice of global radio astronomy activities. The agenda items of WRC-19 covered frequency allocations proposed for a wide range of radiocommunication services. On top of these are the new 5G frequency allocations identified by the conference in the bands 24.25–27.5 GHz, 37–43.5 GHz and 66–71 GHz. The compatibility studies carried out by CRAF and other Radio Astronomy Service (RAS) groups showed the potential interfering impact of these allocations on the RAS observations using the 23.6–24 GHz and 42.5–43.5 GHz bands. The studies recommended introducing separation zones around radio observatories away from the 5G services to mitigate interference. The final acts agreed by the conference invited the national administrations to take the necessary actions in order to protect the RAS observatories from potential interference expected from the 5G services. The overall results of WRC-19 are satisfactory for CRAF and the RAS community in general. The agenda of the next world radiocommunication conference WRC-23 was also approved at the end of the conference. It is now necessary for the radio astronomy observatories to closely coordinate with their national administrations in order to follow up with the WRC- 19 results and prepare for the next cycle towards WRC-23. The OSO CRAF member, apart from being the chairman, focuses also on interference issues at local and national levels (e.g. via contacts with the Swedish Post- och telestyrelsen, PTS). An example of an issue during 2019 concerned the inquiry “Frekvenser i samhällets tjänst (SOU 2018:92)”, from the Swedish government.

Figure 7.1. CRAF participated in the WRC-19 in Sharm el-Sheikh (Egypt) represented by its Frequency Manager Waleed Madkour (left) and its chairman Michael Lindqvist (right).

8 Memberships of International Committees

During 2019 OSO was represented on the following international boards and coordinating committees. The OSO Infrastructure Director John Conway serves on many of these boards.

– AENEAS an EU-financed Horizon 2020 project to develop a concept and design for a distributed, European Science Data Centre for SKA (the Director is a board and Management Team member) – 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). 35

– The APEX project board – representing the three partners that operate the 12 m diamters sub-mm telescope APEX in northern Chile (the Director is a board member) – 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; In addition, until December 2019 Hans Olofsson was a member of the Finance Committee, superceeded by Margareta Wallqvist, Chalmers Operations Support) – SKA Dish Design Consortium (the Director is a board member) – SKA Wide-Band Single Pixel Feed Design Consortium and Advanced Single Pixel Feed and Receiver (ASPFR) Advanced Instrumentation Programme (the Director is the leader of the Consortium). – SKA Phased Array Feed Advanced Instrumentation Programme (The Director is board member). – SKA Regional Centre Steering Committee (The Director is a member). – SKA communications steering committee (Robert Cumming is a member) – 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) – 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]

Durin the year OSO participated in four EU Horizon 2020 projects (proposals submitted in 2016 and 2017): RadioNet, AENEAS, 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:

• 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 will run for four years (until December 2020).

9.2 AENEAS

The large size, rate, and complexity of the data that the SKA will generate, all present challenges to data management, computing, and networking. The objective of the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project is to develop a concept and design for a distributed, European Science Data Centre (ESDC) to support the astronomical community in achieving the scientific goals of the SKA. AENEAS brings together all the European member states currently part of the SKA project as well as potential future EU SKA national partners, the SKA Organisation itself, and a larger group of international partners including the two host countries Australia and South Africa. (See also Sect. 5.3.) AENEAS started January 2017 and ended December 2019.

9.3 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 (until January 2021).

9.4 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 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 (until May 2021).

10 Conferences, workshops, schools, etc.

European Radio Interferometry School 2019 The eighth European Radio Interferometry School (ERIS) was organised by Onsala Space Observatory in Gothenburg October 7-11, 2019. ERIS is a bi-annual graduate level school that forms a fundamental part of the training and development of young radio astronomers primarily from Europe, but also from RadioNet partner countries throughout the world. The school has both lectures and practical tutorials that are given by invited specialists in interferometry who have the expertise and experience in using the main European radio astronomy facilities, which include the Atacama Large Millimetre/Sub-millimetre Array (ALMA), the e-Multi-Element Remotely Linked Interferometry Network (e-MERLIN), the European VLBI Network (EVN), the Low Frequency Array (LOFAR) and the Northern Extended Millimetre Array (NOEMA). ERIS workshops are open to all regardless of their ethnicity, gender and academic position. In total, 72 participants from 28 countries attended the 2019 school, see Fig. 10.1. The vast majority of the participants were at graduate level (Masters/PhD students). The gender ratio (females vs males) for both students and lectures/tutors were close to 50:50. The event received funding from Chalmers and the European Union's Horizon 2020 research and innovation programme under grant agreement No. 730562 RadioNet.

Figure 10.1. Participants in the ERIS 2019. Photo taken during a visit to Onsala Space Observatory. Credit: Magnus Thomasson, Chalmers.

International Symposium on Space THz Technology (ISSTT2019) The 30th International Symposium on Space THz Technology was organised by Onsala Space Observatory/GARD in Gothenburg April 15-17, 2019 (see Fig. 10.2). The scope of the symposium was millimetre, submillimetre and Terahertz technologies and components for applications in astronomy, planetary and Earth science and remote sensing. A total of 138 registered participants from 15 countries attended the symposium, with 107 papers spread over 13 oral sessions and one poster session. Five invited talks were given by prominent scientists, with some of them leading new large instruments.

Figure 10.2. Participants in the International Symposium on Space THz Technology (ISSTT2019). Credit: Erik Sundin, Chalmers.

European ARC Network Software Tools Workshop Among the Nordic ARC node activities (see section 1.2), the development of software tools has historically been a key contribution towards offering tailored user support. The Nordic ARC node has been quite unique in the European ARC Network when it comes to the number and variety of tools developed in recent years. As ALMA develops, the need for new tools emerges and in turn the maintenance and support of existing tools requires assessment. In order to put together the software tools development efforts carried out in the different European ARC nodes and discuss future developments, the node organized a workshop in Chalmersska Huset (Gothenburg, 23-25 September 2019). The workshop had a total of 15 participants with a good representation of the different nodes in the network (Allegro in the Netherlands, IRAM, Bonn, ESO node, UK node, PACE and Nordic ARC). The program was organised to present and discuss all the different existing tools and allow for plenty of discussion time on the future needs for development. As an outcome of the workshop, a software tools working team with members from the different nodes was created. Future workshops with the aim to follow up the working group efforts will be organized on a yearly basis.

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 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 visited the Observatory as part of the course Experimental physics. Additionally, students from Stockholm University visited the Observatory to carry out observations with the 20 m telescope and to learn about radio astronomy.

12 Outreach

Outreach activities at OSO are not part of the VR funded national infrastructure but are funded entirely by Chalmers. During 2019 just over 1400 people visited Onsala Space Observatory, its telescopes and exhibition. Most came as part of a total of 35 guided tours, of which school groups of all ages accounted for 17 of the tours. Around 450 of these visitors to Onsala came as part of three public open days, during the Gothenburg Science Festival, on the Mothers’ day open day in May and in conjunction with Rymdveckan in September. OSO staff took a major role in planning and organisation of Rymdveckan i Västsverige (Space Week in West Sweden, 14-22 September, timed to occur in the year of the 50th anniversary of the first moon-landing). In addition to bus tours to the observatory, two workshops were held for high school students on black holes and climate science, and public talks by guest professors. Onsala-based scientists participated in many other events. During the year planning continued for a new visitor centre at the observatory. A ground-breaking ceremony was held on site during Rymdvecka on 19 September with 150 guests present. 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). At the end of July Chalmers was again host to Rymdforskarskolan, a summer school for high school students interested in space and astronomy, organised by Astronomisk Ungdom (the Swedish Astronomical Youth Association). Several staff members contributed with guest lectures and labs, and a whole day visit to the observatory at Onsala. Our two small SALSA radio telescopes were booked for an average of nearly 46 hours per week, with on average 3.7 h per booking, by students, teachers and amateur astronomers from 25 countries. This includes Sweden but also from as far away as the US, India, Kenya, and Honduras. Most users study the movements of interstellar gas in the Milky Way. We provided supervision for Swedish high school projects using SALSA. SALSA was used to demonstrate and teach radio astronomy to the general public in multiple outreach activities, held both at Onsala and elsewhere. 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 LOFAR’s sky survey and new results from ALMA and the EVN. We organised the Swedish press event in April for the release of the Event Horizon Telescope’s image of a

black hole, and provided support for our host department’s launch event in December for ESA’s exoplanet satellite Cheops. The staff handled many 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, for example during Sweden’s Day and Night of Astronomy in September. Finally, we supported a production company who recorded part of the UR youth science fiction series Spegelvänd on site in July.

13 Changes in organisation [Module 1]

During 2019 an internal reorganization of Onsala Space Observatory was implemented, reducing the number of sub-units from six to five, and reallocating some staff between units. The reduction in units was accomplished by the merger of the Electronics Laboratory and Mechanical Workshop to form a new unit; Technical Development and Support. The other units remain as follows; Group for Advanced Receiver Development (GARD), Space Geodesy and Geodynamics, Observational Support and Computer Support. The reorganization resulted in units of more similar size with a more logical grouping of activities. During 2019 Lars Pettersson, who at the beginning of the year was temporary head of the Electronics Laboratory, was promoted to be permanent head of the new Technical Development and Support unit, and Lars Wennerbäck the previous head of the Mechanical workshop unit was appointed as operationally responsible for mechanical workshop activities within the new Technical Development and Support unit. Another staff change involved Matthias Maercker stepping down as head of the Nordic ALMA Regional Centre function within the Observational Support unit and being replaced by new staff member Carmen Toribio. During 2019 the new top-level OSO management structure established at the end of 2018 was fully implemented. This structure involves the sharing of responsibilities between John Conway, as OSO Scientific/Infrastructure Director and Eva Wirström, as OSO Division Head/Infrastucture Deputy Director. Under this new arrangement the OSO Director is responsible for setting the scientific/technical goals, policies of the infrastructure under the supervision of the OSO Steer Group while the Division Head deals with issues related to the normal employment responsibilities toward staff within the Chalmers management structure. There were no changes to the membership of the OSO Time Allocation Committee (TAC) nor of the OSO Steering Committee (for the current membership of both committees see http://www.chalmers.se/en/centres/oso/about-us/Pages/Organization.aspx). The OSO Steering Committee worked closely with the OSO Director in preparing a proposal to VR for Sweden to join the construction and operations phases of the Square Kilometre Array (SKA) telescope (submitted in February). In addition, a new OSO strategic plan covering 2020-2030 was submitted to VR in June 2019. In September 2019 VR announced conditional approval of the submitted SKA proposal and began a dialogue with OSO and its Steering Committee on defining a new grant to begin sometime in 2020. It is planned that this new contract will cover both the costs of radio astronomy operations at OSO and the Swedish annual contribution to the SKA project.

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 2019 Patrik Carlsson of Chalmers Industrial Technology and Big Science Sweden took over the SKA Industrial Liaison Officer (ILO) role. Big Science Sweden (https://www.bigsciencesweden.se) is a recently formed organisation which promotes technological and industrial return to Sweden from international Big Science infrastructures. Within the SKA project Sweden was during 2019 allocated Level 1 leadership of the SKA1-mid Band 1 and SKA1-mid Digitizer work packages. During the year discussions led by CIT have occurred with several Swedish companies that could act as prime contractors for supplying Band 1 receivers and Digitizers. 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 area of industrial involvement in SKA, is in AI and machine learning, in which Chalmers has a leading position within Sweden. Some initial meetings in this area were set up at Chalmers during 2019. 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.

Acronyms

AENEAS Advanced European Network of E-infrastructures for Astronomy with the SKA AETHRA Advanced European Technologies for Heterodyne Receivers for Astronomy (part of RadioNet) AGN Active Galactic Nucleus AIP Advanced Instrumentation Programme (SKA) ALMA Atacama Large Millimeter/submillimeter Array (Chile) APEX Atacama Pathfinder Experiment (Chile) ARC ALMA Regional Centre ASPFR Advanced Single Pixel Feed and Receiver 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 CIT Chalmers Industrial Technology CO Carbon monoxide (molecule frequently observed by radio telescopes) CoI / Co-I Co-investigator CRAF Committee on Radio Astronomy Frequencies (ESF)

DBBC Digital Base Band Converter (equipment for VLBI observations) DDT Director’s Discretionary Time

EC European Commission EHT Event Horizon Telescope ERIC European Research Infrastructure Consortium ESDC European Science and Data Centre (SKA) ESF European Science Foundation ESO European Southern Observatory EU European Union EUREF IAG Reference Frame Sub-Commission for Europe EVGA The European VLBI Group for Geodesy and Astrometry EVN European VLBI Network

GARD Group for Advanced Receiver Development (part of OSO) GLONASS GLObal NAvigation Satellite System GMVA Global Millimeter VLBI Array GNSS Global Navigational Satellite Systems GPS Global Positioning System GRACE Gravity Recovery and Climate Experiment (satellites) GSAC Galileo Scientific Advisory Committee of the European Space Agency

IAG The International Association of Geodesy ICSU International Council for Science IERS International Earth Rotation and Reference Frame Service IF Intermediate frequency IGETS International Geodynamics and Earth Tide Service

IGS The International GNSS Service ILO Industrial Liaison Officer ILT International LOFAR Telescope IRAM Institut de radioastronomie millimétrique IRDC Infrared Dark Cloud 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)

KSP Key Science Project

LNA Low-Noise Amplifier LOFAR Low Frequency Array LOFAR4SW LOFAR for Space Weather (EU Horizon 2020 project)

MC2 Department of Microtechnology and Nanoscience at Chalmers MeerKAT Radio telescope in South Africa MWA Murchison Widefield Array (radio astronomy array in Western Australia)

NDACC Network for the Detection of Atmospheric Composition Change

OSO Onsala Space Observatory OTT Onsala Twin Telescope

PAF Phased Array Feeds PI Principal Investigator

RadioNet Advanced Radio Astronomy in Europe (EU Horizon 2020 project) RFI Radio Frequency Interference or Rådet för forskningens infrastrukturer vid VR (The Council for Research Infrastructures at VR) 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 host department at Chalmers) SEPIA Swedish ESO PI receiver for APEX SEST Swedish-ESO Submillimetre Telescope (Chile) SIS Superconductor-Insulator-Superconductor SKA Square Kilometre Array SKAO Square Kilometre Array Organisation SLR Satellite Laser Ranging SMHI Sveriges meteorologiska och hydrologiska institut (Swedish Meteorological and Hydrological Institute) SNIC Swedish National Infrastructure for Computing SN Supernova

SNR Signal-to-Noise Ratio, Supernova Remnant 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 TEC Total Electron Content

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 VLBI Very Long Baseline Interferometry VR Vetenskapsrådet, The Swedish Research Council

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

Publications 2019

This section lists publications in refereed journals 2019 enabled by the Onsala infrastructure, divided by instrument and separated in two groups: with or without a Swedish author. For the technical publications by OSO staff, conference proceedings are included. 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 (104/65) (Nordic/Swedish) thereof with explicit Nordic ARC node support (19/16) (Nordic/Swedish) • APEX observations (all APEX partners’ observing time) (65/12) (total/Swedish) • Astronomical VLBI obs. w. EHT, EVN or GMVA, or using JIVE (35/15) (total/Swedish) • LOFAR observations (74/11) (total/Swedish) • Geoscience (OSO instruments specifically stated) (49/17) (total/Swedish) • Onsala 20 m telescope, single-dish observations (4/1) (total/Swedish) • Technical publications about, e.g., receiver development, by OSO staff (8)

In addition to the publications listed below, in 2019 there was 1 publication using astronomical data from the satellite Odin (now operating mainly in aeronomy mode), and 6 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 och 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. Geosci. Advances in Geosciences AJ Astonomical Journal ApJ Astrophysical Journal Astron. Comput. Astronomy and Computing Astropart. Phys. Astroparticle Physcis Atmos. Chem. Phys. Atmospheric Chemistry and Physics CAA Chinese Astronomy and Astrophysics JAI Journal of Astronomical Instrumentation J. Geod. Journal of Geodesy MNRAS Monthly Notices of the Royal Astronomical Society PASJ Publications of the Astronomical Society of Japan PASP Publications of the Astronomical Society of the Pacific RAA Research in Astronomy and Astrophysics RMxAA Revista Mexicana de Astronomia y Astrofisica Space Sci. Rev. Space Science Reviews

ALMA, publications in refereed journals 2019, with Nordic authors

Swedish authors (ALMA)

The hidden heart of the luminous infrared galaxy IC 860. I. A molecular inflow feeding opaque, extreme nuclear activity. Aalto, S., Muller, S., König, S., Falstad, N., Mangum, J., Sakamoto, K., Privon, G.C., Gallagher, J., Combes, F., Garcia-Burillo, S., Martin, S., Viti, S., van der Werf, P., Evans, A.S., Black, J.H., Varenius, E., Beswick, R., Fuller, G., Henkel, C., Kohno, K., Alatalo, K., and Mühle, S. A&A 627, A147 (2019)

A Superluminous Supernova in High Surface Density Molecular Gas within the Bar of a Metal-rich Galaxy. Arabsalmani, M., Roychowdhury, S., Renaud, F., Cormier, D., Le Floc'h, E., Emsellem, E., Perley, D.A., Zwaan, M.A., Bournaud, F., Arumugam, V., and Møller, P. ApJ 882, 31 (2019)

ALMA captures feeding and feedback from the active galactic nucleus in NGC 613. Audibert, A., Combes, F., Garcia-Burillo, S., Hunt, L., Eckart, A., Aalto, S., Casasola, V., Boone, F., Krips, M., Viti, S., Muller, S., Dasyra, K., van der Werf, P., and Martin, S. A&A 632, A33 (2019)

Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular clouds. Barnes, A.T., Longmore, S.N., Avison, A., Contreras, Y., Ginsburg, A., Henshaw, J.D., Rathborne, J.M., Walker, D.L., Alves, J., Bally, J., Battersby, C., Beltran, M.T., Beuther, H., Garay, G., Gomez, L., Jackson, J., Kainulainen, J., Kruijssen, J.M.D., Lu, X., Mills, E.A.C., Ott, J., and Peters, T. MNRAS 486, 283 (2019)

Kinematics around the B335 protostar down to au scales. Bjerkeli, P., Ramsey, J.P., Harsono, D., Calcutt, H., Kristensen, L.E., van der Wiel, M.H.D., Jørgensen, J.K., Muller, S., and Persson, M.V. A&A 631, A64 (2019)

ALMA observations of the "fresh" carbon-rich AGB star TX Piscium. The discovery of an elliptical detached shell. Brunner, M., Mecina, M., Maercker, M., Dorfi, E.A., Kerschbaum, F., Olofsson, H., and Rau, G. A&A 621, A50 (2019)

Molecular complexity on disc scales uncovered by ALMA. Chemical composition of the high- mass protostar AFGL 4176. Bøgelund, E.G., Barr, A.G., Taquet, V., Ligterink, N.F.W., Persson, M.V., Hogerheijde, M.R., and van Dishoeck, E.F. A&A 628, A2 (2019)

The ALMA-PILS survey: propyne (CH3CCH) in IRAS 16293-2422. Calcutt, H., Willis, E.R., Jørgensen, J.K., Bjerkeli, P., Ligterink, N.F.W., Coutens, A., Müller, H.S.P., Garrod, R.T., Wampfler, S.F., and Drozdovskaya, M.N. A&A 631, A137 (2019)

Constraints on high-J CO emission lines in z~6 quasars. Carniani, S., Gallerani, S., Vallini, L., Pallottini, A., Tazzari, M., Ferrara, A., Maiolino, R., Cicone, C., Feruglio, C., Neri, R., D'Odorico, V., Wang, R., and Li, J. MNRAS 489, 3939 (2019)

Physical Characterization of an Unlensed, Dusty Star-forming Galaxy at z=5.85. Casey, C.M., Zavala, J.A., Aravena, M., Bethermin, M., Caputi, K.I., Champagne, J.B., Clements, D.L., da Cunha, E., Drew, P., Finkelstein, S.L., Hayward, C.C., Kartaltepe, J.S., Knudsen, K., Koekemoer, A.M., Magdis, G.E., Man, A., Manning, S.M., Scoville, N.Z., Sheth, K., Spilker, J., Staguhn, J., Talia, M., Taniguchi, Y., Toft, S., Treister, E., and Yun, M. ApJ 887, 55 (2019)

High Angular Resolution ALMA Images of Dust and Molecules in the SN 1987A Ejecta. Cigan, P., Matsuura, M., Gomez, H.L., Indebetouw, R., Abellan, F., Gabler, M., Richards, A., Alp, D., Davis, T.A., Janka, H.-T., Spyromilio, J., Barlow, M.J., Burrows, D., Dwek, E., Fransson, C., Gaensler, B., Larsson, J., Bouchet, P., Lundqvist, P., Marcaide, J.M., Ng, C.-Y., Park, S., Roche, P., van Loon, J.T., Wheeler, J.C., and Zanardo, G. ApJ 886, 51 (2019)

ALMA observations of molecular tori around massive black holes. Combes, F., Garcia-Burillo, S., Audibert, A., Hunt, L., Eckart, A., Aalto, S., Casasola, V., Boone, F., Krips, M., Viti, S., Sakamoto, K., Muller, S., Dasyra, K., van der Werf, P., and Martin, S. A&A 623, A79 (2019)

Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks. Cosentino, G., Jimenez-Serra, I., Caselli, P., Henshaw, J.D., Barnes, A.T., Tan, J.C., Viti, S., Fontani, F., and Wu, B. ApJ 881, L42 (2019)

The ALMA-PILS survey: First detection of nitrous acid (HONO) in the interstellar medium. Coutens, A., Ligterink, N.F.W., Loison, J.-C., Wakelam, V., Calcutt, H., Drozdovskaya, M.N., Jørgensen, J.K., Müller, H.S.P., van Dishoeck, E.F., and Wampfler, S.F. A&A 623, L13 (2019)

ALMA reveals the magnetic field evolution in the high-mass star forming complex G9.62+0.19. Dall'Olio, D., Vlemmings, W.H.T., Persson, M.V., Alves, F.O., Beuther, H., Girart, J.M., Surcis, G., Torrelles, J.M., and Van Langevelde, H.J. A&A 626, A36 (2019)

Reduction of the maximum mass-loss rate of OH/IR stars due to unnoticed binary interaction. Decin, L., Homan, W., Danilovich, T., de Koter, A., Engels, D., Waters, L.B.F.M., Muller, S., Gielen, C., Garcia-Hernandez, D.A., Stancliffe, R.J., Van de Sande, M., Molenberghs, G., Kerschbaum, F., Zijlstra, A.A., and El Mellah, I. Nature Astronomy 3, 408 (2019)

A Radio Source Coincident with the Superluminous Supernova PTF10hgi: Evidence for a Central Engine and an Analog of the Repeating FRB 121102?. Eftekhari, T., Berger, E., Margalit, B., Blanchard, P.K., Patton, L., Demorest, P., Williams, P.K.G., Chatterjee, S., Cordes, J.M., Lunnan, R., Metzger, B.D., and Nicholl, M. ApJ 876, L10 (2019)

Star Formation Efficiencies at Giant Molecular Cloud Scales in the Molecular Disk of the Elliptical Galaxy NGC 5128 (Centaurus A). Espada, D., Verley, S., Miura, R.E., Israel, F.P., Henkel, C., Matsushita, S., Vila-Vilaro, B., Ott, J., Morokuma-Matsui, K., Peck, A.B., Hirota, A., Aalto, S., Quillen, A.C., Hogerheijde, M.R., Neumayer, N., Vlahakis, C., Iono, D., and Kohno, K. ApJ 887, 88 (2019)

First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L4 (2019)

First M87 Event Horizon Telescope Results. III. Data Processing and Calibration. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L3 (2019)

First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L5 (2019)

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L6 (2019)

First M87 Event Horizon Telescope Results. II. Array and Instrumentation. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L2 (2019)

First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L1 (2019)

Hidden or missing outflows in highly obscured galaxy nuclei?. Falstad, N., Hallqvist, F., Aalto, S., König, S., Muller, S., Aladro, R., Combes, F., Evans, A.S., Fuller, G.A., Gallagher, J.S., Garcia-Burillo, S., Gonzalez-Alfonso, E., Greve, T.R., Henkel, C., Imanishi, M., Izumi, T., Mangum, J.G., Martin, S., Privon, G.C., Sakamoto, K., Veilleux, S., and van der Werf, P.P. A&A 623, A29 (2019)

ALMA Reveals a Gas-rich, Maximum Starburst in the Hyperluminous, Dust-obscured Quasar W0533-3401 at z~2.9. Fan, L., Knudsen, K.K., Han, Y., and Tan, Qing-hua. ApJ 887, 74 (2019)

Gas infall and possible circumstellar rotation in R Leonis. Fonfria, J.P., Santander-Garcia, M., Cernicharo, J., Velilla-Prieto, L., Agundez, M., Marcelino, N., and Quintana-Lacaci, G. A&A 622, L14 (2019)

ALMA images the many faces of the NGC 1068 torus and its surroundings. Garcia-Burillo, S., Combes, F., Ramos Almeida, C., Usero, A., Alonso-Herrero, A., Hunt, L.K., Rouan, D., Aalto, S., Querejeta, M., Viti, S., van der Werf, P.P., Vives-Arias, H., Fuente, A., Colina, L., Martin-Pintado, J., Henkel, C., Martin, S., Krips, M., Gratadour, D., Neri, R., and Tacconi, L.J. A&A 632, A61 (2019)

First M87 Event Horizon Telescope Results and the Role of ALMA. Goddi, C., Crew, G., Impellizzeri, V., Marti-Vidal, I., Matthews, L.D., Messias, H., Rottmann, H., Alef, W., Blackburn, L., Bronzwaer, T., Chan, C.-K., Davelaar, J., Deane, R., Dexter, J., Doeleman, S., Falcke, H., Fish, V.L., Fraga-Encinas, R., Fromm, C.M., Herrero-Illana, R., Issaoun, S., James, D., Janssen, M., Kramer, M., Krichbaum, T.P., De Laurentis, M., Liuzzo, E., Mizuno, Y., Moscibrodzka, M., Natarajan, I., Porth, O., Rezzolla, L., Rygl, K., Roelofs, F., Ros, E., Roy, A.L., Shao, L., van Langevelde, H.J., van Bemmel, I., Tilanus, R., Torne, P., Wielgus, M., Younsi, Z., Zensus, J.A., and Event Horizon Telescope Collaboration. The Messenger 177, 25 (2019)

Calibration of ALMA as a Phased Array. ALMA Observations During the 2017 VLBI Campaign. Goddi, C., Marti-Vidal, I., Messias, H., Crew, G.B., Herrero-Illana, R., Impellizzeri, V., Rottmann, H., Wagner, J., Fomalont, E., Matthews, L.D., Petry, D., Phillips, N., Tilanus, R., Villard, E., Blackburn, L., Janssen, M., and Wielgus, M. PASP 131, 75003 (2019)

Big Three Dragons: A z = 7.15 Lyman-break galaxy detected in [O III] 88 micron, [C II] 158 micron, and dust continuum with ALMA. Hashimoto, T., Inoue, A.K., Mawatari, K., Tamura, Y., Matsuo, H., Furusawa, H., Harikane, Y., Shibuya, T., Knudsen, K.K., Kohno, K., Ono, Y., Zackrisson, E., Okamoto, T., Kashikawa, N., Oesch, P.A., Ouchi, M., Ota, K., Shimizu, I., Taniguchi, Y., Umehata, H., and Watson, D. PASJ 71, 71 (2019)

ALMA Reveals Potential Evidence for Spiral Arms, Bars, and Rings in High-redshift Submillimeter Galaxies. Hodge, J.A., Smail, I., Walter, F., da Cunha, E., Swinbank, A.M., Rybak, M., Venemans, B., Brandt, W.N., Calistro Rivera, G., Chapman, S.C., Chen, C.-C., Cox, P., Dannerbauer, H., Decarli, R., Greve, T.R., Knudsen, K.K., Menten, K.M., Schinnerer, E., Simpson, J.M., van der Werf, P., Wardlow, J.L., and Weiss, A. ApJ 876, 130 (2019)

Magnetic field at a jet base: extreme Faraday rotation in 3C 273 revealed by ALMA. Hovatta, T., O'Sullivan, S., Marti-Vidal, I., Savolainen, T., and Tchekhovskoy, A. A&A 623, A111 (2019)

The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA. Issaoun, S., Johnson, M.D., Blackburn, L., Brinkerink, C.D., Moscibrodzka, M., Chael, A., Goddi, C., Marti-Vidal, I., Wagner, J., Doeleman, S.S., Falcke, H., Krichbaum, T.P., Akiyama, K., Bach, U., Bouman, K.L., Bower, G.C., Broderick, A., Cho, I., Crew, G., Dexter, J., Fish, V., Gold, R., Gomez, J.L., Hada, K., Hernandez-Gomez, A., Janßen, M., Kino, M., Kramer, M., Loinard, L., Lu, R.-S., Markoff, S., Marrone, D.P., Matthews, L.D., Moran, J.M., Müller, C., Roelofs, F., Ros, E., Rottmann, H., Sanchez, S., Tilanus, R.P.J., de Vicente, P., Wielgus, M., Zensus, J.A., and Zhao, G.-Y. ApJ 871, 30 (2019)

ALMA observations of water deuteration: a physical diagnostic of the formation of protostars. Jensen, S.S., Jørgensen, J.K., Kristensen, L.E., Furuya, K., Coutens, A., van Dishoeck, E.F., Harsono, D., and Persson, M.V. A&A 631, A25 (2019)

Detection of highly excited OH towards AGB stars. A new probe of shocked gas in the extended atmospheres. Khouri, T., Velilla-Prieto, L., De Beck, E., Vlemmings, W.H.T., Olofsson, H., Lankhaar, B., Black, J.H., and Baudry, A. A&A 623, L1 (2019)

Spatially resolved origin of millimeter-wave linear polarization in the nuclear region of 3C 84. Kim, J.-Y., Krichbaum, T.P., Marscher, A.P., Jorstad, S.G., Agudo, I., Thum, C., Hodgson, J.A., MacDonald, N.R., Ros, E., Lu, R.-S., Bremer, M., de Vicente, P., Lindqvist, M., Trippe, S., and Zensus, J.A. A&A 622, A196 (2019)

ALMACAL - VI. Molecular gas mass density across cosmic time via a blind search for intervening molecular absorbers. Klitsch, A., Péroux, C., Zwaan, M.A., Smail, I., Nelson, D., Popping, G., Chen, C.-C., Diemer, B., Ivison, R.J., Allison, J.R., Muller, S., Swinbank, A.M., Hamanowicz, A., Biggs, A.D., and Dutta, R. MNRAS 490, 1220 (2019)

Widespread Molecular Outflows in the Infrared Dark Cloud G28.37+0.07: Indications of Orthogonal Outflow-filament Alignment. Kong, S., Arce, H.G., Maureira, M.J., Caselli, P., Tan, J.C., and Fontani, F. ApJ 874, 104 (2019)

A Three-dimensional View of Molecular Hydrogen in SN 1987A. Larsson, J., Spyromilio, J., Fransson, C., Indebetouw, R., Matsuura, M., Abellan, F.J., Cigan, P., Gomez, H., and Leibundgut, B. ApJ 873, 15 (2019)

Observation of inverse Compton emission from a long γ-ray burst. MAGIC Collaboration, …, Axelsson, M., et al. Nature 575, 459 (2019)

Fire in the Heart: A Characterization of the High Kinetic Temperatures and Heating Sources in the Nucleus of NGC 253. Mangum, J.G., Ginsburg, A.G., Henkel, C., Menten, K.M., Aalto, S., and van der Werf, P. ApJ 871, 170 (2019)

The ALMA-PILS survey: the first detection of doubly deuterated methyl formate (CHD2OCHO) in the ISM. Manigand, S., Calcutt, H., Jørgensen, J.K., Taquet, V., Müller, H.S.P., Coutens, A., Wampfler, S.F., Ligterink, N.F.W., Drozdovskaya, M.N., Kristensen, L.E., van der Wiel, M.H.D., and Bourke, T.L. A&A 623, A69 (2019)

Spatially resolved carbon and oxygen isotopic ratios in NGC 253 using optically thin tracers. Martin, S., Muller, S., Henkel, C., Meier, D.S., Aladro, R., Sakamoto, K., and van der Werf, P.P. A&A 624, A125 (2019)

Submillimeter polarization and variability of quasar PKS 1830-211. Marti-Vidal, I. and Muller, S. A&A 621, A18 (2019)

The ALMA Discovery of the Rotating Disk and Fast Outflow of Cold Molecular Gas in NGC 1275. Nagai, H., Onishi, K., Kawakatu, N., Fujita, Y., Kino, M., Fukazawa, Y., Lim, J., Forman, W., Vrtilek, J., Nakanishi, K., Noda, H., Asada, K., Wajima, K., Ohyama, Y., David, L., and Daikuhara, K. ApJ 883, 193 (2019)

WISDOM project - V. Resolving molecular gas in Keplerian rotation around the supermassive black hole in NGC 0383. North, E.V., Davis, T.A., Bureau, M., Cappellari, M., Iguchi, S., Liu, L., Onishi, K., Sarzi, M., Smith, M.D., and Williams, T.G. MNRAS 490, 319 (2019)

HD 101584: circumstellar characteristics and evolutionary status. Olofsson, H., Khouri, T., Maercker, M., Bergman, P., Doan, L., Tafoya, D., Vlemmings, W.H.T., Humphreys, E.M.L., Lindqvist, M., Nyman, L., and Ramstedt, S. A&A 623, A153 (2019)

A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922. Sanchez Contreras, C., Baez-Rubio, A., Alcolea, J., Castro-Carrizo, A., Bujarrabal, V., Martin-Pintado, J., and Tafoya, D. A&A 629, A136 (2019)

The ALMA Survey of 70 micron Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation. Sanhueza, P., Contreras, Y., Wu, B., Jackson, J.M., Guzman, A.E., Zhang, Q., Li, S., Lu, X., Silva, A., Izumi, N., Liu, T., Miura, R.E., Tatematsu, K., Sakai, T., Beuther, H., Garay, G., Ohashi, S., Saito, M., Nakamura, F., Saigo, K., Veena, V.S., Nguyen-Luong, Q., and Tafoya, D. ApJ 886, 102 (2019)

A spectral stacking analysis to search for faint outflow signatures in z~6 quasars. Stanley, F., Jolly, J.B., König, S., and Knudsen, K.K. A&A 631, A78 (2019)

Spatio-kinematical model of the collimated molecular outflow in the water-fountain nebula IRAS 16342-3814. Tafoya, D., Orosz, G., Vlemmings, W.H.T., Sahai, R., and Perez-Sanchez, A.F. A&A 629, A8 (2019)

Detection of the Far-infrared [O III] and Dust Emission in a Galaxy at Redshift 8.312: Early Metal Enrichment in the Heart of the Reionization Era. Tamura, Y., Mawatari, K., Hashimoto, T., Inoue, A.K., Zackrisson, E., Christensen, L., Binggeli, C., Matsuda, Y., Matsuo, H., Takeuchi, T.T., Asano, R.S., Sunaga, K., Shimizu, I., Okamoto, T., Yoshida, N., Lee, M.M., Shibuya, T., Taniguchi, Y., Umehata, H., Hatsukade, B., Kohno, K., and Ota, K. ApJ 874, 27 (2019)

ALMA view of the 12C/13C isotopic ratio in starburst galaxies. Tang, X.D., Henkel, C., Menten, K.M., Gong, Y., Martin, S., Mühle, S., Aalto, S., Muller, S., Garcia-Burillo, S., Levshakov, S., Aladro, R., Spaans, M., Viti, S., Asiri, H.M., Ao, Y.P., Zhang, J.S., Zheng, X.W., Esimbek, J., and Zhou, J.J. A&A 629, A6 (2019)

Interferometric observations of warm deuterated methanol in the inner regions of low-mass protostars. Taquet, V., Bianchi, E., Codella, C., Persson, M.V., Ceccarelli, C., Cabrit, S., Jørgensen, J.K., Kahane, C., Lopez-Sepulcre, A., and Neri, R. A&A 632, A19 (2019)

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. I. Identifying and Characterizing the Protostellar Content of the OMC-2 FIR4 and OMC-2 FIR3 Regions. Tobin, J.J., Megeath, S.T., van't Hoff, M., Diaz-Rodriguez, A.K., Reynolds, N., Osorio, M., Anglada, G., Furlan, E., Karnath, N., Offner, S.S.R., Sheehan, P.D., Sadavoy, S.I., Stutz, A.M., Fischer, W.J., Kama, M., Persson, M., Di Francesco, J., Looney, L.W., Watson, D.M., Li, Z.-Y., Stephens, I., Chandler, C.J., Cox, E., Dunham, M.M., Kratter, K., Kounkel, M., Mazur, B., Murillo, N.M., Patel, L., Perez, L., Segura-Cox, D., Sharma, R., Tychoniec, L., and Wyrowski, F. ApJ 886, 6 (2019)

An ALMA/HST Study of Millimeter Dust Emission and Star Clusters. Turner, J.A., Dale, D.A., Adamo, A., Calzetti, D., Grasha, K., Grebel, E.K., Johnson, K.E., Lee, J.C., Smith, L.J., and Yoon, I. ApJ 884, 112 (2019)

Chlorine-bearing molecules in molecular absorbers at intermediate redshifts. Wallström, S.H.J., Muller, S., Roueff, E., Le Gal, R., Black, J.H., and Gerin, M. A&A 629, A128 (2019)

The ALMA-PILS survey: gas dynamics in IRAS 16293-2422 and the connection between its two protostars. van der Wiel, M.H.D., Jacobsen, S.K., Jørgensen, J.K., Bourke, T.L., Kristensen, L.E., Bjerkeli, P., Murillo, N.M., Calcutt, H., Müller, H.S.P., Coutens, A., Drozdovskaya, M.N., Favre, C., and Wampfler, S.F. A&A 626, A93 (2019)

IRC + 10°216 mass loss properties through the study of 3 mm emission. Large spatial scale distribution of SiO, SiS, and CS. Velilla-Prieto, L., Cernicharo, J., Agundez, M., Fonfria, J.P., Quintana-Lacaci, G., Marcelino, N., and Castro-Carrizo, A. A&A 629, A146 (2019)

Resolving the extended stellar atmospheres of asymptotic giant branch stars at (sub)millimetre wavelengths. Vlemmings, W.H.T., Khouri, T., and Olofsson, H. A&A 626, A81 (2019)

Stringent limits on the magnetic field strength in the disc of TW Hya. ALMA observations of CN polarisation. Vlemmings, W.H.T., Lankhaar, B., Cazzoletti, P., Ceccobello, C., Dall'Olio, D., van Dishoeck, E.F., Facchini, S., Humphreys, E.M.L., Persson, M.V., Testi, L., and Williams, J.P. A&A 624, L7 (2019)

An Ordered Envelope-Disk Transition in the Massive Protostellar Source G339.88-1.26. Zhang, Y., Tan, J.C., Sakai, N., Tanaka, K.E.I., De Buizer, J.M., Liu, M., Beltran, M.T., Kratter, K., Mardones, D., and Garay, G. ApJ 873, 73 (2019)

Dynamics of a massive binary at birth. Zhang, Y., Tan, J.C., Tanaka, K.E.I., De Buizer, J.M., Liu, M., Beltrán, M.T., Kratter, K., Mardones, D., and Garay, G. Nature Astronomy 3, 517 (2019)

Discovery of a Photoionized Bipolar Outflow toward the Massive Protostar G45.47+0.05. Zhang, Y., Tanaka, K.E.I., Rosero, V., Tan, J.C., Marvil, J., Cheng, Y., Liu, M., Beltran, M.T., and Garay, G. ApJ 886, L4 (2019)

Nordic authors (ALMA)

Nuclear molecular outflow in the Seyfert galaxy NGC 3227. Alonso-Herrero, A., Garcia-Burillo, S., Pereira-Santaella, M., Davies, R.I., Combes, F., Vestergaard, M., Raimundo, S.I., Bunker, A., Diaz-Santos, T., Gandhi, P., Garcia-Bernete, I., Hicks, E.K.S., Hönig, S.F., Hunt, L.K., Imanishi, M., Izumi, T., Levenson, N.A., Maciejewski, W., Packham, C., Ramos Almeida, C., Ricci, C., Rigopoulou, D., Roche, P.F., Rosario, D., Schartmann, M., Usero, A., and Ward, M.J. A&A 628, A65 (2019)

Imaging the molecular interstellar medium in a gravitationally lensed star-forming galaxy at z = 5.7. Apostolovski, Y., Aravena, M., Anguita, T., Spilker, J., Weiß, A., Bethermin, M., Chapman, S.C., Chen, C.-C., Cunningham, D., De Breuck, C., Dong, C., Hayward, C.C., Hezaveh, Y., Jarugula, S., Litke, K., Ma, J., Marrone, D.P., Narayanan, D., Reuter, C.A., Rotermund, K., and Vieira, J. A&A 628, A23 (2019)

The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Evolution of the Molecular Gas in CO-selected Galaxies. Aravena, M., Decarli, R., Gónzalez-López, J., Boogaard, L., Walter, F., Carilli, C., Popping, G., Weiss, A., Assef, R.J., Bacon, R., Bauer, F.E., Bertoldi, F., Bouwens, R., Contini, T., Cortes, P.C., Cox, P., da Cunha, E., Daddi, E., Díaz-Santos, T., Elbaz, D., Hodge, J., Inami, H., Ivison, R., Le Fèvre, O., Magnelli, B., Oesch, P., Riechers, D., Smail, I., Somerville, R.S., Swinbank, A.M., Uzgil, B., van der Werf, P., Wagg, J., and Wisotzki, L. ApJ 882, 136 (2019)

Physical and chemical fingerprint of protostellar disc formation. Artur de la Villarmois, E., Jørgensen, J.K., Kristensen, L.E., Bergin, E.A., Harsono, D., Sakai, N., van Dishoeck, E.F., and Yamamoto, S. A&A 626, A71 (2019)

Suppressed CO emission and high G/D ratios in z = 2 galaxies with sub-solar gas-phase metallicity. Coogan, R.T., Sargent, M.T., Daddi, E., Valentino, F., Strazzullo, V., Bethermin, M., Gobat, R., Liu, D., and Magdis, G. MNRAS 485, 2092 (2019)

15 Laboratory spectroscopic study of the N isotopomers of cyanamide, H2NCN, and a search for them toward IRAS 16293-2422 B. Coutens, A., Zakharenko, O., Lewen, F., Jørgensen, J.K., Schlemmer, S., and Müller, H.S.P. A&A 623, A93 (2019)

The ALMA Spectroscopic Survey in the HUDF: CO Luminosity Functions and the Molecular Gas Content of Galaxies through Cosmic History. Decarli, R., Walter, F., Gónzalez-López, J., Aravena, M., Boogaard, L., Carilli, C., Cox, P., Daddi, E., Popping, G., Riechers, D., Uzgil, B., Weiss, A., Assef, R.J., Bacon, R., Bauer, F.E., Bertoldi, F., Bouwens, R., Contini, T., Cortes, P.C., da Cunha, E., Díaz-Santos, T., Elbaz, D., Inami, H., Hodge, J., Ivison, R., Le Fèvre, O., Magnelli, B., Novak, M., Oesch, P., Rix, H.-W., Sargent, M.T., Smail, I., Swinbank, A.M., Somerville, R.S., van der Werf, P., Wagg, J., and Wisotzki, L. ApJ 882, 138 (2019)

Ingredients for solar-like systems: protostar IRAS 16293-2422 B versus comet 67P/Churyumov-Gerasimenko. Drozdovskaya, M.N., van Dishoeck, E.F., Rubin, M., Jørgensen, J.K., and Altwegg, K. MNRAS 490, 50 (2019)

Sunyaev-Zel'dovich detection of the galaxy cluster Cl J1449+0856 at z = 1.99: The pressure profile in uv space. Gobat, R., Daddi, E., Coogan, R.T., Le Brun, A.M.C., Bournaud, F., Melin, J.-B., Riechers, D.A., Sargent, M., Valentino, F., Hwang, H.S., Finoguenov, A., and Strazzullo, V. A&A 629, A104 (2019)

Confirming Herschel Candidate Protoclusters from ALMA/VLA CO Observations. Gomez-Guijarro, C., Riechers, D.A., Pavesi, R., Magdis, G.E., Leung, T.K.D., Valentino, F., Toft, S., Aravena, M., Chapman, S.C., Clements, D.L., Dannerbauer, H., Oliver, S.J., Perez-Fournon, I., and Valtchanov, I. ApJ 872, 117 (2019)

Molecular and Ionized Gas Phases of an AGN-driven Outflow in a Typical Massive Galaxy at z~2. Herrera-Camus, R., Tacconi, L., Genzel, R., Förster Schreiber, N., Lutz, D., Bolatto, A., Wuyts, S., Renzini, A., Lilly, S., Belli, S., Übler, H., Shimizu, T., Davies, R., Sturm, E., Combes, F., Freundlich, J., Garcia-Burillo, S., Cox, P., Burkert, A., Naab, T., Colina, L., Saintonge, A., Cooper, M., Feruglio, C., and Weiss, A. ApJ 871, 37 (2019)

Chronology of Episodic Accretion in Protostars - An ALMA Survey of the CO and H2O Snowlines. Hsieh, T.-H., Murillo, N.M., Belloche, A., Hirano, N., Walsh, C., van Dishoeck, E.F., Jørgensen, J.K., and Lai, S.-P. ApJ 884, 149 (2019)

Organic chemistry in the innermost, infalling envelope of the Class 0 protostar L483. Jacobsen, S.K., Jørgensen, J.K., Di Francesco, J., Evans, N.J., Choi, M., and Lee, J.-E. A&A 629, A29 (2019)

The solar chromosphere at millimetre and ultraviolet wavelengths. I. Radiation temperatures and a detailed comparison. Jafarzadeh, S., Wedemeyer, S., Szydlarski, M., De Pontieu, B., Rezaei, R., and Carlsson, M. A&A 622, A150 (2019)

Spatially Resolved Water Emission from Gravitationally Lensed Dusty Star-forming Galaxies at z~3. Jarugula, S., Vieira, J.D., Spilker, J.S., Apostolovski, Y., Aravena, M., Bethermin, M., de Breuck, C., Chen, C.-C., Cunningham, D.J.M., Dong, C., Greve, T., Hayward, C.C., Hezaveh, Y., Litke, K.C., Mangian, A.C., Narayanan, D., Phadke, K., Reuter, C.A., Van der Werf, P., and Weiss, A. ApJ 880, 92 (2019)

Discovery of Four Apparently Cold Dusty Galaxies at z=3.62-5.85 in the COSMOS Field: Direct Evidence of Cosmic Microwave Background Impact on High-redshift Galaxy Observables. Jin, S., Daddi, E., Magdis, G.E., Liu, D., Schinnerer, E., Papadopoulos, P.P., Gu, Q., Gao, Y., and Calabro A. ApJ 887, 144 (2019)

MUSE-AO view of the starburst-AGN connection: NGC 7130. Knapen, J.H., Comeron, S., and Seidel, M.K. A&A 621, L5 (2019)

The Molecular Outflow in NGC 253 at a Resolution of Two Parsecs. Krieger, N., Bolatto, A.D., Walter, F., Leroy, A.K., Zschaechner, L.K., Meier, D.S., Ott, J., Weiss, A., Mills, E.A.C., Levy, R.C., Veilleux, S., and Gorski, M. ApJ 881, 43 (2019)

Revealing the Stellar Mass and Dust Distributions of Submillimeter Galaxies at Redshift 2. Lang, P., Schinnerer, E., Smail, I., Dudzeviciute, U., Swinbank, A.M., Liu, D., Leslie, S.K., Almaini, O., An, F.X., Bertoldi, F., Blain, A.W., Chapman, S.C., Chen, C.-C., Conselice, C., Cooke, E.A., Coppin, K.E.K., Dunlop, J.S., Farrah, D., Fudamoto, Y., Geach, J.E., Gullberg, B., Harrington, K.C., Hodge, J.A., Ivison, R.J., Jimenez-Andrade, E.F., Magnelli, B., Michalowski, M.J., Oesch, P., Scott, D., Simpson, J.M., Smolcic, V., Stach, S.M., Thomson, A.P., Toft, S., Vardoulaki, E., Wardlow, J.L., Weiss, A., and van der Werf, P. ApJ 879, 54 (2019)

Characterizing Magnetic Field Morphologies in Three Serpens Protostellar Cores with ALMA. Le Gouellec, V.J.M., Hull, C.L.H., Maury, A.J., Girart, J.M., Tychoniec, L., Kristensen, L.E., Li, Z.-Y., Louvet, F., Cortes, P.C., and Rao, R. ApJ 885, 106 (2019)

Spatially Resolved [C II] Emission in SPT0346-52: A Hyper-starburst Galaxy Merger at z~5.7. Litke, K.C., Marrone, D.P., Spilker, J.S., Aravena, M., Bethermin, M., Chapman, S., Chen, C.-C., de Breuck, C., Dong, C., Gonzalez, A., Greve, T.R., Hayward, C.C., Hezaveh, Y., Jarugula, S., Ma, J., Morningstar, W., Narayanan, D., Phadke, K., Reuter, C., Vieira, J., and Weiss, A. ApJ 870, 80 (2019)

Automated Mining of the ALMA Archive in the COSMOS Field (A^3COSMOS). II. Cold Molecular Gas Evolution out to Redshift 6. Liu, D., Schinnerer, E., Groves, B., Magnelli, B., Lang, P., Leslie, S., Jimenez-Andrade, E., Riechers, D.A., Popping, G., Magdis, G.E., Daddi, E., Sargent, M., Gao, Y., Fudamoto, Y., Oesch, P.A., and Bertoldi, F. ApJ 887, 235 (2019)

VALES V: a kinematic analysis of the molecular gas content in H-ATLAS galaxies at z~0.03-0.35 using ALMA. Molina, J., Ibar, E., Villanueva, V., Escala, A., Cheng, C., Baes, M., Messias, H., Yang, C., Bauer, F.E., van der Werf, P., Leiton, R., Aravena, M., Swinbank, A.M., Michalowski, M.J., Munoz-Arancibia, A.M., Orellana, G., Hughes, T.M., Farrah, D., De Zotti, G., Lara- Lopez, M.A., Eales, S., and Dunne, L. MNRAS 482, 1499 (2019)

MUSE observations of a changing-look AGN - I. The reappearance of the broad emission lines. Raimundo, S.I., Vestergaard, M., Koay, J.Y., Lawther, D., Casasola, V., and Peterson, B.M. MNRAS 486, 123 (2019)

First Spectral Analysis of a Solar Plasma Eruption Using ALMA. Rodger, A.S., Labrosse, N., Wedemeyer, S., Szydlarski, M., Simoes, P.J.A., and Fletcher, L. ApJ 875, 163 (2019)

Active Galactic Nuclei in Dusty Starbursts at z = 2: Feedback Still to Kick in. Rodighiero, G., Enia, A., Delvecchio, I., Lapi, A., Magdis, G.E., Rujopakarn, W., Mancini, C., Rodriguez-Munoz, L., Carraro, R., Iani, E., Negrello, M., Franceschini, A., Renzini, A., Gruppioni, C., Perna, M., Baronchelli, I., Puglisi, A., Cassata, P., Daddi, E., Morselli, L., and Silverman, J. ApJ 877, L38 (2019)

ALMA 200 pc Resolution Imaging of Smooth Cold Dusty Disks in Typical z~3 Star-forming Galaxies. Rujopakarn, W., Daddi, E., Rieke, G.H., Puglisi, A., Schramm, M., Perez-Gonzalez, P.G., Magdis, G.E., Alberts, S., Bournaud, F., Elbaz, D., Franco, M., Kawinwanichakij, L., Kohno, K., Narayanan, D., Silverman, J.D., Wang, T., and Williams, C.C. ApJ 882, 107 (2019)

A Catastrophic Failure to Build a Massive Galaxy around a Supermassive Black Hole at z = 3.84. Schramm, M., Rujopakarn, W., Silverman, J.D., Nagao, T., Schulze, A., Akiyama, M., Ikeda, H., Ohta, K., and Kotilainen, J. ApJ 881, 145 (2019)

No signs of star formation being regulated in the most luminous quasars at z~2 with ALMA. Schulze, A., Silverman, J.D., Daddi, E., Rujopakarn, W., Liu, D., Schramm, M., Mainieri, V., Imanishi, M., Hirschmann, M., and Jahnke, K. MNRAS 488, 1180 (2019)

ALMA, ATCA, and Spitzer Observations of the Luminous Extragalactic Supernova SN 1978K. Smith, I.A., Ryder, S.D., Kotak, R., Kool, E.C., and Randall, S.K. ApJ 870, 59 (2019)

Evidence for Inside-out Galaxy Growth and Quenching of a z~2 Compact Galaxy From High- resolution Molecular Gas Imaging. Spilker, J.S., Bezanson, R., Weiner, B.J., Whitaker, K.E., and Williams, C.C. ApJ 883, 81 (2019)

The Formation Conditions of the Wide Binary Class 0 Protostars within BHR 71. Tobin, J.J., Bourke, T.L., Mader, S., Kristensen, L., Arce, H., Gueth, F., Gusdorf, A., Codella, C., Leurini, S., and Chen, X. ApJ 870, 81 (2019)

Chemical and kinematic structure of extremely high-velocity molecular jets in the Serpens Main star-forming region. Tychoniec, L., Hull, C.L.H., Kristensen, L.E., Tobin, J.J., Le Gouellec, V.J.M., and van Dishoeck, E.F. A&A 632, A101 (2019)

Resolving the Interstellar Medium in the Nuclear Region of Two z=5.78 Quasar Host Galaxies with ALMA. Wang, R., Shao, Y., Carilli, C.L., Jones, G.C., Walter, F., Fan, X., Riechers, D.A., Decarli, R., Bertoldi, F., Wagg, J., Strauss, M.A., Omont, A., Cox, P., Jiang, L., Narayanan, D., Menten, K.M., and Venemans, B.P. ApJ 887, 40 (2019)

Evolution of the Gas Mass Fraction of Progenitors to Today's Massive Galaxies: ALMA Observations in the CANDELS GOODS-S Field. Wiklind, T., Ferguson, H.C., Guo, Y., Koo, D.C., Kocevski, D., Mobasher, B., Brammer, G.B., Kassin, S., Koekemoer, A.M., Giavalisco, M., Papovich, C., Ravindranath, S., Faber, S.M., Freundlich, J., and de Mello, D.F. ApJ 878, 83 (2019)

Discovery of a Dark, Massive, ALMA-only Galaxy at z~5-6 in a Tiny 3 mm Survey. Williams, C.C., Labbe, I., Spilker, J., Stefanon, M., Leja, J., Whitaker, K., Bezanson, R., Narayanan, D., Oesch, P., and Weiner, B. ApJ 884, 154 (2019)

The ALMA Fornax Cluster Survey I: stirring and stripping of the molecular gas in cluster galaxies. Zabel, N., Davis, T.A., Smith, M.W.L., Maddox, N., Bendo, G.J., Peletier, R., Iodice, E., Venhola, A., Baes, M., Davies, J.I., de Looze, I., Gomez, H., Grossi, M., Kenney, J.D.P., Serra, P., van de Voort, F., Vlahakis, C., and Young, L.M. MNRAS 483, 2251 (2019)

Deuterated methyl mercaptan (CH3SD): Laboratory rotational spectroscopy and search toward IRAS 16293-2422 B. Zakharenko, O., Lewen, F., Ilyushin, V.V., Drozdovskaya, M.N., Jørgensen, J.K., Schlemmer, S., and Müller, H.S.P. A&A 621, A114 (2019)

On the Gas Content, Star Formation Efficiency, and Environmental Quenching of Massive Galaxies in Protoclusters at z~2.0-2.5. Zavala, J.A., Casey, C.M., Scoville, N., Champagne, J.B., Chiang, Y., Dannerbauer, H., Drew, P., Fu, H., Spilker, J., Spitler, L., Tran, K.V., Treister, E., and Toft, S. ApJ 887, 183 (2019)

APEX, publications in refereed journals 2019

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

Swedish authors (APEX)

Kinematics around the B335 protostar down to au scales. Bjerkeli, Per, Ramsey, Jon P., Harsono, Daniel, Calcutt, Hannah, Kristensen, Lars E., van der Wiel, Matthijs H. D., Jørgensen, Jes K., Muller, Sébastien, Persson, Magnus V. A&A 631, A64 (2019)

First M87 Event Horizon Telescope Results. II. Array and Instrumentation. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L2 (2019)

Calibration of ALMA as a Phased Array. ALMA Observations During the 2017 VLBI Campaign. Goddi, C., Martí-Vidal, I., Messias, H., Crew, G.B., Herrero-Illana, R., Impellizzeri, V., Rottmann, H., Wagner, J., Fomalont, E., Matthews, L.D., Petry, D., Phillips, N., Tilanus, R., Villard, E., Blackburn, L., Janssen, M., and Wielgus, M. PASP 131, 75003 (2019)

APEX Millimeter Observations of Methanol Emission Toward High-mass Star-forming Cores. Hernández-Hernández, Vicente, Kurtz, Stan, Kalenskii, Sergei, Golysheva, Polina, Garay, Guido, Zapata, Luis, Bergman, Per. AJ 158, 18 (2019)

Weak-lensing mass calibration of the Sunyaev-Zel'dovich effect using APEX-SZ galaxy clusters. Nagarajan, A., Pacaud, F., Sommer, M., Klein, M., Basu, K., Bertoldi, F., Lee, A. T., Ade, P. A. R., Bender, A. N., Ferrusca, D., Halverson, N. W., Horellou, C., Johnson, B. R., Kennedy, J., Kneissl, R., Menten, K. M., Reichardt, C. L., Tucker, C., Westbrook, B. MNRAS 488, 1728 (2019)

HD 101584: circumstellar characteristics and evolutionary status. Olofsson, H., Khouri, T., Maercker, M., Bergman, P., Doan, L., Tafoya, D., Vlemmings, W. H. T., Humphreys, E. M. L., Lindqvist, M., Nyman, L., Ramstedt, S. A&A 623, A153 (2019)

The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation. Sanhueza, Patricio, Contreras, Yanett, Wu, Benjamin, Jackson, James M., Guzmán, Andrés E., Zhang, Qizhou, Li, Shanghuo, Lu, Xing, Silva, Andrea, Izumi, Natsuko, Liu, Tie, Miura, Rie E., Tatematsu, Ken’ichi, Sakai, Takeshi, Beuther, Henrik, Garay, Guido, Ohashi, Satoshi, Saito, Masao, Nakamura, Fumitaka, Saigo, Kazuya, Veena, V. S., Nguyen-Luong, Quang, Tafoya, Daniel. ApJ 886, 102 (2019)

International authors (APEX)

Imaging the molecular interstellar medium in a gravitationally lensed star-forming galaxy at z = 5.7. Apostolovski, Yordanka, Aravena, Manuel, Anguita, Timo, Spilker, Justin, Weiß, Axel, Béthermin, Matthieu, Chapman, Scott C., Chen, Chian-Chou, Cunningham, Daniel, De Breuck, Carlos, Dong, Chenxing, Hayward, Christopher C., Hezaveh, Yashar, Jarugula, Sreevani, Litke, Katrina, Ma, Jingzhe, Marrone, Daniel P., Narayanan, Desika, Reuter, Cassie A., Rotermund, Kaja, Vieira, Joaquin. A&A 628, A23 (2019)

Revealing the chemical structure of the Class I disc Oph-IRS 67. Artur de la Villarmois, E., Kristensen, L. E., Jørgensen, J. K. A&A 627, A37 (2019)

The RMS survey: Ammonia mapping of the environment of young massive stellar objects - II. Billington, S. J., Urquhart, J. S., Figura, C., Eden, D. J., Moore, T. J. T. MNRAS 483, 3146 (2019)

ATLASGAL - physical parameters of dust clumps associated with 6.7 GHz methanol masers. Billington, S. J., Urquhart, J. S., König, C., Moore, T. J. T., Eden, D. J., Breen, S. L., Kim, W. -J., Thompson, M. A., Ellingsen, S. P., Menten, K. M., Wyrowski, F., Leurini, S. MNRAS 490, 2779 (2019)

Large Molecular Gas Reservoirs in Star-forming Cluster Galaxies. Cairns, Joseph, Stroe, Andra, De Breuck, Carlos, Mroczkowski, Tony, Clements, David. ApJ 882, 132 (2019)

12CO and 13CO J = 3-2 observations toward N11 in the Large Magellanic Cloud. Celis Peña, M., Paron, S., Rubio, M., Herrera, C. N., Ortega, M. E. A&A 628, A96 (2019)

Multiline Observations of Molecular Bullets from a High-mass Protostar. Cheng, Yu, Qiu, Keping, Zhang, Qizhou, Wyrowski, Friedrich, Menten, Karl, Güsten, Rolf. ApJ 877, 112 (2019)

A dense, solar metallicity ISM in the z = 4.2 dusty star-forming galaxy SPT 0418-47. De Breuck, Carlos, Weiß, Axel, Béthermin, Matthieu, Cunningham, Daniel, Apostolovski, Yordanka, Aravena, Manuel, Archipley, Melanie, Chapman, Scott, Chen, Chian-Chou, Fu, Jianyang, Jarugula, Sreevani, Malkan, Matt, Mangian, Amelia C., Phadke, Kedar A., Reuter, Cassie A., Stacey, Gordon, Strandet, Maria, Vieira, Joaquin, Vishwas, Amit. A&A 631, A167 (2019)

Unveiling Molecular Clouds toward Bipolar H II Region G8.14+0.23. Dewangan, L. K., Sano, H., Enokiya, R., Tachihara, K., Fukui, Y., Ojha, D. K. ApJ 878, 26 (2019)

Molecular Gas in the Outflow of the Small Magellanic Cloud. Di Teodoro, Enrico M., McClure-Griffiths, N. M., De Breuck, C., Armillotta, L., Pingel, N. M., Jameson, K. E., Dickey, John M., Rubio, M., Stanimirović, S., Staveley-Smith, L. ApJL 885, L32 (2019)

Beyond the solar circle - trends in massive star formation between the inner and outer galaxy. Djordjevic, J. O., Thompson, M. A., Urquhart, J. S., Forbrich, J. MNRAS 487, 1057 (2019)

Cyanoacetylene in the outflow/hot molecular core G331.512-0.103. Duronea, N. U., Bronfman, L., Mendoza, E., Merello, M., Finger, R., Reyes, N., Hervías-Caimapo, C., Faure, A., Cappa, C. E., Arnal, E. M., Lépine, J. R. D., Kleiner, I., Nyman, L.-Å. MNRAS 489, 1519 (2019)

Multiwavelength study of the G345.5+1.5 region. Figueira, M., López-Calderón, C., Bronfman, L., Zavagno, A., Hervías-Caimapo, C., Duronea, N., Nyman, L.-Å. A&A 623, A141 (2019)

Origin of the PN molecule in star-forming regions: the enlarged sample. Fontani, F., Rivilla, V. M., van der Tak, F. F. S., Mininni, C., Beltrán, M. T., Caselli, P. MNRAS 489, 4530 (2019)

+ + A timeline for massive star-forming regions via combined observation of o-H2D and N2D . Giannetti, A., Bovino, S., Caselli, P., Leurini, S., Schleicher, D. R. G., Körtgen, B., Menten, K. M., Pillai, T., Wyrowski, F. A&A 621, L7 (2019)

Warm gas in protostellar outflows. II. Extremely high-velocity emission jet and outflows from OMC-2/3. Gómez-Ruiz, A. I., Gusdorf, A., Leurini, S., Menten, K. M., Takahashi, S., Wyrowski, F., Güsten, R. A&A 629, A77 (2019)

The `Red Radio Ring': ionized and molecular gas in a starburst/active galactic nucleus at z ⁓ 2.55. Harrington, Kevin C., Vishwas, A., Weiß, A., Magnelli, B., Grassitelli, L., Zajaček, M., Jiménez-Andrade, E. F., Leung, T. K. D., Bertoldi, F., Romano-Díaz, E., Frayer, D. T., Kamieneski, P., Riechers, D., Stacey, G. J., Yun, M. S., Wang, Q. D. MNRAS 488, 1489 (2019)

Modelling the abundance structure of isocyanic acid (HNCO) towards the low-mass solar type protostar IRAS 16293-2422. Hernández-Gómez, Antonio, Sahnoun, Emna, Caux, Emmanuel, Wiesenfeld, Laurent, Loinard, Laurent, Bottinelli, Sandrine, Hammami, Kamel, Menten, Karl M. MNRAS 483, 2014 (2019)

Initial phases of high-mass star formation: a multiwavelength study towards the extended green object G12.42+0.50. Issac, Namitha, Tej, Anandmayee, Liu, Tie, Varricatt, Watson, Vig, Sarita, Ishwara Chandra, C. H., Schultheis, Mathias. MNRAS 485, 1775 (2019)

Asymmetric Line Profiles in Dense Molecular Clumps Observed in MALT90: Evidence for Global Collapse. Jackson, James M., Whitaker, J. Scott, Rathborne, J. M., Foster, J. B., Contreras, Y., Sanhueza, Patricio, Stephens, Ian W., Longmore, S. N., Allingham, David. ApJ 870, 5 (2019)

Spatially Resolved Water Emission from Gravitationally Lensed Dusty Star-forming Galaxies at z 3. Jarugula, Sreevani, Vieira, Joaquin D., Spilker, Justin S., Apostolovski, Yordanka, Aravena,∼ Manuel, Béthermin, Matthieu, de Breuck, Carlos, Chen, Chian-Chou, Cunningham, Daniel J. M., Dong, Chenxing, Greve, Thomas, Hayward, Christopher C., Hezaveh, Yashar, Litke, Katrina C., Mangian, Amelia C., Narayanan, Desika, Phadke, Kedar, Reuter, Cassie A., Van der Werf, Paul, Weiss, Axel. ApJ 880, 92 (2019)

Molecular envelope around the HII region RCW 120. Kirsanova, M. S., Pavlyuchenkov, Ya N., Wiebe, D. S., Boley, P. A., Salii, S. V., Kalenskii, S. V., Sobolev, A. M., Anderson, L. D. MNRAS 488, 5641 (2019)

Prevalence of SED Turndown among Classical Be Stars: Are All Be Stars Close Binaries?. Klement, Robert, Carciofi, A. C., Rivinius, T., Ignace, R., Matthews, L. D., Torstensson, K., Gies, D., Vieira, R. G., Richardson, N. D., Domiciano de Souza, A., Bjorkman, J. E., Hallinan, G., Faes, D. M., Mota, B., Gullingsrud, A. D., de Breuck, C., Kervella, P., Curé, M., Gunawan, D. ApJ 885, 147 (2019)

Characterising the high-mass star forming filament G351.776-0.527 with Herschel and APEX dust continuum and gas observations. Leurini, S., Schisano, E., Pillai, T., Giannetti, A., Urquhart, J., Csengeri, T., Casu, S., Cunningham, M., Elia, D., Jones, P. A., König, C., Molinari, S., Stanke, T., Testi, L., Wyrowski, F., Menten, K. M. A&A 621, A130 (2019)

Testing the weak equivalence principle by differential measurements of fundamental constants in the Magellanic Clouds. Levshakov, S. A., Ng, K. -W., Henkel, C., Mookerjea, B., Agafonova, I. I., Liu, S. -Y., Wang, W. -H. MNRAS 487, 5175 (2019)

Spatial Variation of the Chemical Properties of Massive Star-forming Clumps. Li, Mingyue, Zhou, Jianjun, Esimbek, Jarken, Quan, Donghui, He, Yuxin, Li, Qiang, Zhu, Chunhua. ApJS 243, 13 (2019)

Molecular environs and triggered star formation around the large Galactic infrared bubble N 24. Li, Xu, Esimbek, Jarken, Zhou, Jianjun, Baan, W. A., Ji, Weiguang, Tang, Xindi, Wu, Gang, Tang, Xiaoke, Li, Qiang, Ma, Yingxiu, Sailanbek, Serikbek, Li, Dalei, Alimbetova, Dina. MNRAS 487, 1517 (2019)

Fragmentation and filaments at the onset of star and cluster formation. SABOCA 350 μm view of ATLASGAL-selected massive clumps. Lin, Y., Csengeri, T., Wyrowski, F., Urquhart, J. S., Schuller, F., Weiss, A., Menten, K. M. A&A 631, A72 (2019)

Large-scale periodic velocity oscillation in the filamentary cloud G350.54+0.69. Liu, Hong-Li, Stutz, Amelia, Yuan, Jing-Hua. MNRAS 487, 1259 (2019)

Dense cores and star formation in the giant molecular cloud Vela C. Massi, F., Weiss, A., Elia, D., Csengeri, T., Schisano, E., Giannini, T., Hill, T., Lorenzetti, D., Menten, K., Olmi, L., Schuller, F., Strafella, F., De Luca, M., Motte, F., Wyrowski, F. A&A 628, A110 (2019)

The molecular gas properties in the gravitationally lensed merger HATLAS J142935.3-002836. Messias, Hugo, Nagar, Neil, Zhang, Zhi-Yu, Oteo, Iván, Dye, Simon, Ibar, Eduardo, Timmons, Nicholas, van der Werf, Paul, Riechers, Dominik, Eales, Stephen, Ivison, Rob, Maresca, Jacob, Michałowski, Michał J., Yang, Chentao. MNRAS 486, 2366 (2019)

Opening the Treasure Chest in Carina. Mookerjea, B., Sandell, G., Güsten, R., Riquelme, D., Wiesemeyer, H., Chambers, E. A&A 626, A131 (2019)

ATLASGAL-selected massive clumps in the inner Galaxy. VII. Characterisation of mid-J CO emission. Navarete, F., Leurini, S., Giannetti, A., Wyrowski, F., Urquhart, J. S., König, C., Csengeri, T., Güsten, R., Damineli, A., Menten, K. M. A&A 622, A135 (2019)

Velocity profiles of [CII], [C>I], CO, and [OI] and physical conditions in four star-forming regions in the Large Magellanic Cloud. Okada, Yoko, Güsten, Rolf, Requena-Torres, Miguel Angel, Röllig, Markus, Stutzki, Jürgen, Graf, Urs Ulrich, Hughes, Annie. A&A 621, A62 (2019)

On the diagnostic power of FIR/sub-mm SED fitting in massive galactic molecular clumps. Pitts, Rebecca L., Barnes, Peter J., Varosi, Frank. MNRAS 484, 305 (2019)

CO Multi-line Observations of HH 80─81: A Two-component Molecular Outflow Associated with the Largest Protostellar Jet in Our Galaxy. Qiu, Keping, Wyrowski, Friedrich, Menten, Karl, Zhang, Qizhou, Güsten, Rolf. ApJ 871, 141 (2019)

A flat trend of star formation rate with X-ray luminosity of galaxies hosting AGN in the SCUBA-2 Cosmology Legacy Survey. Ramasawmy, Joanna, Stevens, Jason, Martin, Garreth, Geach, James E. MNRAS 486, 4320 (2019)

GASP - XVII. H I imaging of the jellyfish galaxy JO206: gas stripping and enhanced star formation. Ramatsoku, M., Serra, P., Poggianti, B. M., Moretti, A., Gullieuszik, M., Bettoni, D., Deb, T., Fritz, J., van Gorkom, J. H., Jaffé, Y. L., Tonnesen, S., Verheijen, M. A. W., Vulcani, B., Hugo, B., Józsa, G. I. G., Maccagni, F. M., Makhathini, S., Ramaila, A., Smirnov, O., Thorat, K. MNRAS 487, 4580 (2019)

Weak and Compact Radio Emission in Early High-mass Star-forming Regions. II. The Nature of the Radio Sources. Rosero, V., Hofner, P., Kurtz, S., Cesaroni, R., Carrasco-González, C., Araya, E. D., Rodríguez, L. F., Menten, K. M., Wyrowski, F., Loinard, L., Ellingsen, S. P., Molinari, S. ApJ 880, 99 (2019)

Herschel-HOBYS study of the earliest phases of high-mass star formation in NGC 6357. Russeil, D., Figueira, M., Zavagno, A., Motte, F., Schneider, N., Men'shchikov, A., Bontemps, S., André, P., Anderson, L. D., Benedettini, M., Didelon, P., Di Francesco, J., Elia, D., Könyves, V., Nguyen Luong, Q., Nony, T., Pezzuto, S., Rygl, K. L. J., Schisano, E., Spinoglio, L., Tigé, J., White, G. J. A&A 625, A134 (2019)

On the size of the CO-depletion radius in the IRDC G351.77-0.51. Sabatini, G., Giannetti, A., Bovino, S., Brand, J., Leurini, S., Schisano, E., Pillai, T., Menten, K. M. MNRAS 490, 4489 (2019)

Molecular clumps towards compact H II regions. Saldaño, Hugo P., Rubio, M., Cappa, C. E., Gómez, M. MNRAS 487, 2881 (2019)

Physical conditions in Centaurus A's northern filaments. I. APEX mid-J CO observations of CO-bright regions. Salomé, Q., Salomé, P., Gusdorf, A., Combes, F. A&A 627, A6 (2019)

Observational study of hydrocarbons in the bright photodissociation region of Messier 8. Tiwari, M., Menten, K. M., Wyrowski, F., Pérez-Beaupuits, J. P., Lee, M. -Y., Kim, W. -J. A&A 626, A28 (2019)

SOFIA FORCAST Photometry of 12 Extended Green Objects in the Milky Way. Towner, A. P. M., Brogan, C. L., Hunter, T. R., Cyganowski, C. J., Friesen, R. K. ApJ 875, 135 (2019)

Infrared Galaxies in the Field of the Massive Cluster Abell S1063: Discovery of a Luminous Kiloparsec-sized H II Region in a Gravitationally Lensed Infrared-luminous Galaxy at z = 0.6. Walth, Gregory L., Egami, Eiichi, Clément, Benjamin, Rawle, Timothy D., Rex, Marie, Richard, Johan, Pérez-González, Pablo, Boone, Frédéric, Dessauges-Zavadsky, Miroslava, Portouw, Jeff, Weiner, Benjamin, McGreer, Ian, Schneider, Evan. ApJ 877, 7 (2019)

Millimeter and Far-IR Study of the IRDC SDC 341.232-0.268. Vazzano, M. M., Cappa, C. E., Rubio, M., Firpo, V., López-Caraballo, C. H., Duronea, N. U. RMxAA 55, 289 (2019)

APEX Observations of the CO Envelope around the Young FUor-type Star V883 Ori. White, J. A., Kóspál, Á., Rab, C., Ábrahám, P., Cruz-Sáenz de Miera, F., Csengeri, T., Fehér, O., Güsten, R., Henning, T., Vorobyov, E., Audard, M., Postel, A. ApJ 877, 21 (2019)

The effects of ionization feedback on star formation: a case study of the M 16 H II region. Xu, Jin-Long, Zavagno, Annie, Yu, Naiping, Liu, Xiao-Lan, Xu, Ye, Yuan, Jinghua, Zhang, Chuan-Peng, Zhang, Si-Ju, Zhang, Guo-Yin, Ning, Chang-Chun, Ju, Bing-Gang. A&A 627, A27 (2019)

A search for hypercompact H II regions in the Galactic Plane. Yang, A. Y., Thompson, M. A., Tian, W. W., Bihr, S., Beuther, H., Hindson, L. MNRAS 482, 2681 (2019)

Chemical evolution of HC3N in dense molecular clouds. Yu, Naiping, Wang, Jun-Jie, Xu, Jin-Long. MNRAS 489, 4497 (2019)

A multiwavelength study of filamentary cloud G341.244-00.265. Yu, Nai-Ping, Xu, Jing-Long, Wang, Jun-Jie. A&A 622, A155 (2019)

Probing the initial conditions of high-mass star formation. III. Fragmentation and triggered star formation. Zhang, Chuan-Peng, Csengeri, Timea, Wyrowski, Friedrich, Li, Guang-Xing, Pillai, Thushara, Menten, Karl M., Hatchell, Jennifer, Thompson, Mark A., Pestalozzi, Michele R. A&A 627, A85 (2019)

Astronomical VLBI, publications in refereed journals 2019

Swedish authors (Astro VLBI)

An International Survey of Front-end Receivers and Observing Performance of Telescopes for Radio Astronomy. Bolli, P., Orfei, A., Zanichelli, A., Prestage, R., Tingay, S.J., Beltrán, M., Burgay, M., Contavalle, C., Honma, M., Kraus, A., Lindqvist, M., Lopez Perez, J., Marongiu, P., Minamidani, T., Navarro, S., Pisanu, T., Shen, Z.-Q., Sohn, B.W., Stanghellini, C., Tzioumis, T., and Zacchiroli, G. PASP 131, 85002 (2019)

The loud and the quiet: searching for radio counterparts of two radio-weak BL Lac candidates with VLBI. Cao, H.-M., Frey, S., Gabányi, K.É., Yang, J., Cui, L., Hong, X.-Y., and An, T. MNRAS 482, L34 (2019)

First M87 Event Horizon Telescope Results. II. Array and Instrumentation. Event Horizon Telescope Collaboration: …, Conway, J.E., …, Lindqvist, M., …, Martí-Vidal, I, et al. ApJ 875, L2 (2019)

Compact radio emission indicates a structured jet was produced by a binary neutron star merger. Ghirlanda, G., Salafia, O.S., Paragi, Z., Giroletti, M., Yang, J., Marcote, B., Blanchard, J., Agudo, I., An, T., Bernardini, M.G., Beswick, R., Branchesi, M., Campana, S., Casadio, C., Chassande-Mottin, E., Colpi, M., Covino, S., D'Avanzo, P., D'Elia, V., Frey, S., Gawronski, M., Ghisellini, G., Gurvits, L.I., Jonker, P.G., van Langevelde, H.J., Melandri, A., Moldon, J., Nava, L., Perego, A., Perez-Torres, M.A., Reynolds, C., Salvaterra, R., Tagliaferri, G., Venturi, T., Vergani, S.D., and Zhang, M. Science 363, 968 (2019)

Global millimeter VLBI array survey of ultracompact extragalactic radio sources at 86 GHz. Nair, D.G., Lobanov, A.P., Krichbaum, T.P., Ros, E., Zensus, J.A., Kovalev, Y.Y., Lee, S.-S., Mertens, F., Hagiwara, Y., Bremer, M., Lindqvist, M., and de Vicente, P. A&A 622, A92 (2019)

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions. IV. Magnetic field strength limits and structure for seven additional sources. Surcis, G., Vlemmings, W.H.T., van Langevelde, H.J., Hutawarakorn Kramer, B., and Bartkiewicz, A. A&A 623, A130 (2019)

The population of SNe/SNRs in the starburst galaxy Arp 220. A self-consistent analysis of 20 years of VLBI monitoring. Varenius, E., Conway, J.E., Batejat, F., Martí-Vidal, I., Pérez-Torres, M.A., Aalto, S., Alberdi, A., Lonsdale, C.J., and Diamond, P. A&A 623, A173 (2019)

A radio structure resolved at the deca-parsec scale in the radio-quiet quasar PDS 456 with an extremely powerful X-ray outflow. Yang, J., An, T., Zheng, F., Baan, W.A., Paragi, Z., Mohan, P., Zhang, Z., and Liu, X. MNRAS 482, 1701 (2019)

The jet of FSRQ PKS 1229−02 and its misidentification as a γ-ray AGN. Zhao, W., Hong, X.-Y., An, T., and Yang, J. RAA 19, 179 (2019)

International authors (Astro VLBI)

Potential kick velocity distribution of black hole X-ray binaries and implications for natal kicks. Atri, P., Miller-Jones, J.C.A., Bahramian, A., Plotkin, R.M., Jonker, P.G., Nelemans, G., Maccarone, T.J., Sivakoff, G.R., Deller, A.T., Chaty, S., Torres, M.A.P., Horiuchi, S., McCallum, J., Natusch, T., Phillips, C.J., Stevens, J., and Weston, S. MNRAS 489, 3116 (2019)

EHT-HOPS Pipeline for Millimeter VLBI Data Reduction. Blackburn, L., Chan, C.-. kwan ., Crew, G.B., Fish, V.L., Issaoun, S., Johnson, M.D., Wielgus, M., Akiyama, K., Barrett, J., Bouman, K.L., Cappallo, R., Chael, A.A., Janssen, M., Lonsdale, C.J., and Doeleman, S.S. ApJ 882, 23 (2019)

Venus Express radio occultation observed by PRIDE. Bocanegra-Bahamón, T.M., Molera Calvés, G., Gurvits, L.I., Cimò, G., Dirkx, D., Duev, D.A., Pogrebenko, S.V., Rosenblatt, P., Limaye, S., Cui, L., Li, P., Kondo, T., Sekido, M., Mikhailov, A.G., Kharinov, M.A., Ipatov, A.V., Wang, W., Zheng, W., Ma, M., Lovell, J.E.J., and McCallum, J.N. A&A 624, A59 (2019)

The magnetic field structure in CTA 102 from high-resolution mm-VLBI observations during the flaring state in 2016-2017. Casadio, C., Marscher, A.P., Jorstad, S.G., Blinov, D.A., MacDonald, N.R., Krichbaum, T.P., Boccardi, B., Traianou, E., Gómez, J.L., Agudo, I., Sohn, B.-W., Bremer, M., Hodgson, J., Kallunki, J., Kim, J.-Y., Williamson, K.E., and Zensus, J.A. A&A 622, A158 (2019)

Water masers in Compton-thick AGN. II. The high detection rate and EVN observations of IRAS 15480-0344. Castangia, P., Surcis, G., Tarchi, A., Caccianiga, A., Severgnini, P., and Della Ceca, R. A&A 629, A25 (2019)

Very long baseline interferometry observation of the triple AGN candidate J0849+1114. Gabányi, K.É., Frey, S., Satyapal, S., Constantin, A., and Pfeifle, R.W. A&A 630, L5 (2019)

Strong lensing reveals jets in a sub-microJy radio-quiet quasar. Hartley, P., Jackson, N., Sluse, D., Stacey, H.R., and Vives-Arias, H. MNRAS 485, 3009 (2019)

FRB 121102 Bursts Show Complex Time-Frequency Structure. Hessels, J.W.T., Spitler, L.G., Seymour, A.D., Cordes, J.M., Michilli, D., Lynch, R.S., Gourdji, K., Archibald, A.M., Bassa, C.G., Bower, G.C., Chatterjee, S., Connor, L., Crawford, F., Deneva, J.S., Gajjar, V., Kaspi, V.M., Keimpema, A., Law, C.J., Marcote, B., McLaughlin, M.A., Paragi, Z., Petroff, E., Ransom, S.M., Scholz, P., Stappers, B.W., and Tendulkar, S.P. ApJ 876, L23 (2019)

Probing the origin of the off-pulse emission from the pulsars B0525+21 and B2045-16. Marcote, B., Maan, Y., Paragi, Z., and Keimpema, A. A&A 627, L2 (2019)

Resolving the Decades-long Transient FIRST J141918.9+394036: An Orphan Long Gamma- Ray Burst or a Young Magnetar Nebula?. Marcote, B., Nimmo, K., Salafia, O.S., Paragi, Z., Hessels, J.W.T., Petroff, E., and Karuppusamy, R. ApJ 876, L14 (2019)

A connection between accretion states and the formation of ultrarelativistic outflows in a neutron star X-ray binary. Motta, S.E. and Fender, R.P. MNRAS 483, 3686 (2019)

Feedback from low-luminosity radio galaxies: B2 0258+35. Murthy, S., Morganti, R., Oosterloo, T., Schulz, R., Mukherjee, D., Wagner, A.Y., Bicknell, G., Prandoni, I., and Shulevski, A. A&A 629, A58 (2019)

Statistical Discrimination of RFI and Astronomical Transients in 2-bit Digitized Time Domain Signals. Nita, G.M., Keimpema, A., and Paragi, Z. JAI 8, 1940008 (2019)

6.7 GHz variability characteristics of new periodic methanol maser sources. Olech, M., Szymczak, M., Wolak, P., Sarniak, R., and Bartkiewicz, A. MNRAS 486, 1236 (2019)

Puzzling blue dips in the black hole candidate Swift J1357.2 - 0933, from ULTRACAM, SALT, ATCA, Swift, and NuSTAR. Paice, J.A., Gandhi, P., Charles, P.A., Dhillon, V.S., Marsh, T.R., Buckley, D.A.H., Kotze, M.M., Beri, A., Altamirano, D., Middleton, M.J., Plotkin, R.M., Miller-Jones, J.C.A., Russell, D.M., Tomsick, J., Díaz-Merced, W., and Misra, R. MNRAS 488, 512 (2019)

Is There a Blazar Nested in the Core of the Radio Galaxy 3C 411?. Perger, K., Frey, S., and Gabányi, K.É. ApJ 873, 61 (2019)

An insight into the extragalactic transient and variable microJy radio sky across multiple decades. Radcliffe, J.F., Beswick, R.J., Thomson, A.P., Garrett, M.A., Barthel, P.D., and Muxlow, T.W.B. MNRAS 490, 4024 (2019)

Proper motion in lensed radio jets at redshift 3: A possible dual super-massive black hole system in the early Universe. Spingola, C., McKean, J.P., Massari, D., and Koopmans, L.V.E. A&A 630, A108 (2019)

Radio Properties of BL Lac Object S5 2007+777. Zhen-xu, L., Zhong-zu, W., Yong-jun, C., Liang, C., Min-feng, G., and Li-gong, M. CAA 43, 519 (2019)

LOFAR, publications in refereed journals 2019

Swedish authors (LOFAR)

Signatures from a merging galaxy cluster and its AGN population: LOFAR observations of Abell 1682. Clarke, A.O., Scaife, A.M.M., Shimwell, T., van Weeren, R.J., Bonafede, A., Heald, G., Brunetti, G., Cantwell, T.M., de Gasperin, F., Brüggen, M., Botteon, A., Hoeft, M., Horellou, C., Cassano, R., Harwood, J.J., and Röttgering, H.J.A. A&A 627, A176 (2019) beamModelTester: Software framework for testing radio telescope beams. Creaner, O. and Carozzi, T.D. Astron. Comput. 28, 100311 (2019)

The first power spectrum limit on the 21-cm signal of neutral hydrogen during the Cosmic Dawn at z = 20-25 from LOFAR. Gehlot, B.K., Mertens, F.G., Koopmans, L.V.E., Brentjens, M.A., Zaroubi, S., Ciardi, B., Ghosh, A., Hatef, M., Iliev, I.T., Jelić, V., Kooistra, R., Krause, F., Mellema, G., Mevius, M., Mitra, M., Offringa, A.R., Pandey, V.N., Sardarabadi, A.M., Schaye, J., Silva, M.B., Vedantham, H.K., and Yatawatta, S. MNRAS 488, 4271 (2019)

A radio ridge connecting two galaxy clusters in a filament of the cosmic web. Govoni, F., Orrù, E., Bonafede, A., Iacobelli, M., Paladino, R., Vazza, F., Murgia, M., Vacca, V., Giovannini, G., Feretti, L., Loi, F., Bernardi, G., Ferrari, C., Pizzo, R.F., Gheller, C., Manti, S., Brüggen, M., Brunetti, G., Cassano, R., de Gasperin, F., Enßlin, T.A., Hoeft, M., Horellou, C., Junklewitz, H., Röttgering, H.J.A., Scaife, A.M.M., Shimwell, T.W., van Weeren, R.J., and Wise, M. Science 364, 981 (2019)

Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR. Heesen, V., Buie, E., Huff, C.J., Perez, L.A., Woolsey, J.G., Rafferty, D.A., Basu, A., Beck, R., Brinks, E., Horellou, C., Scannapieco, E., Brüggen, M., Dettmar, R.-J., Sendlinger, K., Nikiel-Wroczyński, B., Chyży, K.T., Best, P.N., Heald, G.H., and Paladino, R. A&A 622, A8 (2019)

Warped diffusive radio halo around the quiescent spiral edge-on galaxy NGC 4565. Heesen, V., Whitler, L., Schmidt, P., Miskolczi, A., Sridhar, S.S., Horellou, C., Beck, R., Gürkan, G., Scannapieco, E., Brüggen, M., Heald, G.H., Krause, M., Paladino, R., Nikiel-Wroczyński, B., Wilber, A., and Dettmar, R.-J. A&A 628, L3 (2019)

CHANG-ES XII. A LOFAR and VLA view of the edge-on star-forming galaxy NGC 3556. Miskolczi, A., Heesen, V., Horellou, C., Bomans, D.-J., Beck, R., Heald, G., Dettmar, R.-J., Blex, S., Nikiel-Wroczyński, B., Chyży, K.T., Stein, Y., Irwin, J.A., Shimwell, T.W., and Wang, Q.D. A&A 622, A9 (2019)

Calibration of the LOFAR low-band antennas using the Galaxy and a model of the signal chain. Mulrey, K., Bonardi, A., Buitink, S., Corstanje, A., Falcke, H., Hare, B.M., Hörandel, J.R., Huege, T., Mitra, P., Nelles, A., Rachen, J.P., Rossetto, L., Schellart, P., Scholten, O., ter Veen, S., Thoudam, S., Trinh, T.N.G., and Winchen, T. Astropart. Phys. 111, 1 (2019)

Exploring the properties of low-frequency radio emission and magnetic fields in a sample of compact galaxy groups using the LOFAR Two-Metre Sky Survey (LoTSS). Nikiel-Wroczyński, B., Berger, A., Herrera Ruiz, N., Bomans, D.J., Blex, S., Horellou, C., Paladino, R., Becker, A., Miskolczi, A., Beck, R., Chyży, K., Dettmar, R.-J., Heald, G., Heesen, V., Jamrozy, M., Shimwell, T.W., and Tasse, C. A&A 622, A23 (2019)

The intergalactic magnetic field probed by a giant radio galaxy. O'Sullivan, S.P., Machalski, J., Van Eck, C.L., Heald, G., Brüggen, M., Fynbo, J.P.U., Heintz, K.E., Lara-Lopez, M.A., Vacca, V., Hardcastle, M.J., Shimwell, T.W., Tasse, C., Vazza, F., Andernach, H., Birkinshaw, M., Haverkorn, M., Horellou, C., Williams, W.L., Harwood, J.J., Brunetti, G., Anderson, J.M., Mao, S.A., Nikiel-Wroczyński, B., Takahashi, K., Carretti, E., Vernstrom, T., van Weeren, R.J., Orrú, E., Morabito, L.K., and Callingham, J.R. A&A 622, A16 (2019)

The LOFAR Two-metre Sky Survey. II. First data release. Shimwell, T.W., Tasse, C., Hardcastle, M.J., Mechev, A.P., Williams, W.L., Best, P.N., Röttgering, H.J.A., Callingham, J.R., Dijkema, T.J., de Gasperin, F., Hoang, D.N., Hugo, B., Mirmont, M., Oonk, J.B.R., Prandoni, I., Rafferty, D., Sabater, J., Smirnov, O., van Weeren, R.J., White, G.J., Atemkeng, M., Bester, L., Bonnassieux, E., Brüggen, M., Brunetti, G., Chyży, K.T., Cochrane, R., Conway, J.E., Croston, J.H., Danezi, A., Duncan, K., Haverkorn, M., Heald, G.H., Iacobelli, M., Intema, H.T., Jackson, N., Jamrozy, M., Jarvis, M.J., Lakhoo, R., Mevius, M., Miley, G.K., Morabito, L., Morganti, R., Nisbet, D., Orrú, E., Perkins, S., Pizzo, R.F., Schrijvers, C., Smith, D.J.B., Vermeulen, R., Wise, M.W., Alegre, L., Bacon, D.J., van Bemmel, I.M., Beswick, R.J., Bonafede, A., Botteon, A., Bourke, S., Brienza, M., Calistro Rivera, G., Cassano, R., Clarke, A.O., Conselice, C.J., Dettmar, R.J., Drabent, A., Dumba, C., Emig, K.L., Enßlin, T.A., Ferrari, C., Garrett, M.A., Génova-Santos, R.T., Goyal, A., Gürkan, G., Hale, C., Harwood, J.J., Heesen, V., Hoeft, M., Horellou, C., Jackson, C., Kokotanekov, G., Kondapally, R., Kunert-Bajraszewska, M., Mahatma, V., Mahony, E.K., Mandal, S., McKean, J.P., Merloni, A., Mingo, B., Miskolczi, A., Mooney, S., Nikiel-Wroczyński, B., O'Sullivan, S.P., Quinn, J., Reich, W., Roskowiński, C., Rowlinson, A., Savini, F., Saxena, A., Schwarz, D.J., Shulevski, A., Sridhar, S.S., Stacey, H.R., Urquhart, S., van der Wiel, M.H.D., Varenius, E., Webster, B., and Wilber, A. A&A 622, A1 (2019)

International authors (LOFAR)

A low-frequency view of mixed-morphology supernova remnant VRO 42.05.01, and its neighbourhood. Arias, M., Vink, J., Iacobelli, M., Domček, V., Haverkorn, M., Oonk, J.B.R., Polderman, I., Reich, W., White, G.J., and Zhou, P. A&A 622, A6 (2019)

Low-frequency Radio Absorption in Tycho’s Supernova Remnant. Arias, M., Vink, J., Zhou, P., de Gasperin, F., Hardcastle, M.J., and Shimwell, T.W. AJ 158, 253 (2019)

A massive cluster at z = 0.288 caught in the process of formation: The case of Abell 959. Bîrzan, L., Rafferty, D.A., Cassano, R., Brunetti, G., van Weeren, R.J., Brüggen, M., Intema, H.T., de Gasperin, F., Andrade-Santos, F., Botteon, A., Röttgering, H.J.A., and Shimwell, T.W. MNRAS 487, 4775 (2019)

Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamics. Botteon, A., Cassano, R., Eckert, D., Brunetti, G., Dallacasa, D., Shimwell, T.W., van Weeren, R.J., Gastaldello, F., Bonafede, A., Brüggen, M., Bîrzan, L., Clavico, S., Cuciti, V., de Gasperin, F., De Grandi, S., Ettori, S., Ghizzardi, S., Rossetti, M., Röttgering, H.J.A., and Sereno, M. A&A 630, A77 (2019)

The spectacular cluster chain Abell 781 as observed with LOFAR, GMRT, and XMM-Newton. Botteon, A., Shimwell, T.W., Bonafede, A., Dallacasa, D., Gastaldello, F., Eckert, D., Brunetti, G., Venturi, T., van Weeren, R.J., Mandal, S., Brüggen, M., Cassano, R., de Gasperin, F., Drabent, A., Dumba, C., Intema, H.T., Hoang, D.N., Rafferty, D., Röttgering, H.J.A., Savini, F., Shulevski, A., Stroe, A., and Wilber, A. A&A 622, A19 (2019)

LOFAR Discovery of a Radio Halo in the High-redshift Galaxy Cluster PSZ2 G099.86+58.45. Cassano, R., Botteon, A., Di Gennaro, G., Brunetti, G., Sereno, M., Shimwell, T.W., van Weeren, R.J., Brüggen, M., Gastaldello, F., Izzo, L., Bîrzan, L., Bonafede, A., Cuciti, V., de Gasperin, F., Röttgering, H.J.A., Hardcastle, M., Mechev, A.P., and Tasse, C. ApJ 881, L18 (2019)

Properties and magnetic origins of solar S-bursts. Clarke, B.P., Morosan, D.E., Gallagher, P.T., Dorovskyy, V.V., Konovalenko, A.A., and Carley, E.P. A&A 622, A204 (2019)

The environments of radio-loud AGN from the LOFAR Two-Metre Sky Survey (LoTSS). Croston, J.H., Hardcastle, M.J., Mingo, B., Best, P.N., Sabater, J., Shimwell, T.M., Williams, W.L., Duncan, K.J., Röttgering, H.J.A., Brienza, M., Gürkan, G., Ineson, J., Miley, G.K., Morabito, L.M., O'Sullivan, S.P., and Prandoni, I. A&A 622, A10 (2019)

Systematic effects in LOFAR data: A unified calibration strategy. de Gasperin, F., Dijkema, T.J., Drabent, A., Mevius, M., Rafferty, D., van Weeren, R., Brüggen, M., Callingham, J.R., Emig, K.L., Heald, G., Intema, H.T., Morabito, L.K., Offringa, A.R., Oonk, R., Orrù, E., Röttgering, H., Sabater, J., Shimwell, T., Shulevski, A., and Williams, W. A&A 622, A5 (2019)

First detection of frequency-dependent, time-variable dispersion measures. Donner, J.Y., Verbiest, J.P.W., Tiburzi, C., Osłowski, S., Michilli, D., Serylak, M., Anderson, J.M., Horneffer, A., Kramer, M., Grießmeier, J.-M., Künsemöller, J., Hessels, J.W.T., Hoeft, M., and Miskolczi, A. A&A 624, A22 (2019)

The LOFAR Two-metre Sky Survey. IV. First Data Release: Photometric redshifts and rest- frame magnitudes. Duncan, K.J., Sabater, J., Röttgering, H.J.A., Jarvis, M.J., Smith, D.J.B., Best, P.N., Callingham, J.R., Cochrane, R., Croston, J.H., Hardcastle, M.J., Mingo, B., Morabito, L., Nisbet, D., Prandoni, I., Shimwell, T.W., Tasse, C., White, G.J., Williams, W.L., Alegre, L., Chyży, K.T., Gürkan, G., Hoeft, M., Kondapally, R., Mechev, A.P., Miley, G.K., Schwarz, D.J., and van Weeren, R.J. A&A 622, A3 (2019)

The first detection of radio recombination lines at cosmological distances. Emig, K.L., Salas, P., de Gasperin, F., Oonk, J.B.R., Toribio, M.C., Röttgering, H.J.A., and Tielens, A.G.G.M. A&A 622, A7 (2019)

The First Detection of a Low-frequency Turnover in Nonthermal Emission from the Jet of a Young Star. Feeney-Johansson, A., Purser, S.J.D., Ray, T.P., Eislöffel, J., Hoeft, M., Drabent, A., and Ainsworth, R.E. ApJ 885, L7 (2019)

Frequency-Distance Structure of Solar Radio Sources Observed by LOFAR. Gordovskyy, M., Kontar, E., Browning, P., and Kuznetsov, A. ApJ 873, 48 (2019)

Observations of a pre-merger shock in colliding clusters of galaxies. Gu, L., Akamatsu, H., Shimwell, T.W., Intema, H.T., van Weeren, R.J., de Gasperin, F., Mernier, F., Mao, J., Urdampilleta, I., de Plaa, J., Parekh, V., Röttgering, H.J.A., and Kaastra, J.S. Nature Astronomy 3, 838 (2019)

LoTSS/HETDEX: Optical quasars. I. Low-frequency radio properties of optically selected quasars. Gürkan, G., Hardcastle, M.J., Best, P.N., Morabito, L.K., Prandoni, I., Jarvis, M.J., Duncan, K.J., Calistro Rivera, G., Callingham, J.R., Cochrane, R.K., Croston, J.H., Heald, G., Mingo, B., Mooney, S., Sabater, J., Röttgering, H.J.A., Shimwell, T.W., Smith, D.J.B., Tasse, C., and Williams, W.L. A&A 622, A11 (2019)

LOFAR observations of the XMM-LSS field. Hale, C.L., Williams, W., Jarvis, M.J., Hardcastle, M.J., Morabito, L.K., Shimwell, T.W., Tasse, C., Best, P.N., Harwood, J.J., Heywood, I., Prandoni, I., Röttgering, H.J.A., Sabater, J., Smith, D.J.B., and van Weeren, R.J. A&A 622, A4 (2019)

NGC 326: X-shaped no more. Hardcastle, M.J., Croston, J.H., Shimwell, T.W., Tasse, C., Gürkan, G., Morganti, R., Murgia, M., Röttgering, H.J.A., van Weeren, R.J., and Williams, W.L. MNRAS 488, 3416 (2019)

Radio-loud AGN in the first LoTSS data release. The lifetimes and environmental impact of jet-driven sources. Hardcastle, M.J., Williams, W.L., Best, P.N., Croston, J.H., Duncan, K.J., Röttgering, H.J.A., Sabater, J., Shimwell, T.W., Tasse, C., Callingham, J.R., Cochrane, R.K., de Gasperin, F., Gürkan, G., Jarvis, M.J., Mahatma, V., Miley, G.K., Mingo, B., Mooney, S., Morabito, L.K., O'Sullivan, S.P., Prandoni, I., Shulevski, A., and Smith, D.J.B. A&A 622, A12 (2019)

Needle-like structures discovered on positively charged lightning branches. Hare, B.M., Scholten, O., Dwyer, J., Trinh, T.N.G., Buitink, S., ter Veen, S., Bonardi, A., Corstanje, A., Falcke, H., Hörandel, J.R., Huege, T., Mitra, P., Mulrey, K., Nelles, A., Rachen, J.P., Rossetto, L., Schellart, P., Winchen, T., Anderson, J., Avruch, I.M., Bentum, M.J., Blaauw, R., Broderick, J.W., Brouw, W.N., Brüggen, M., Butcher, H.R., Ciardi, B., Fallows, R.A., de Geus, E., Duscha, S., Eislöffel, J., Garrett, M.A., Grießmeier, J.M., Gunst, A.W., van Haarlem, M.P., Hessels, J.W.T., Hoeft, M., van der Horst, A.J., Iacobelli, M., Koopmans, L.V.E., Krankowski, A., Maat, P., Norden, M.J., Paas, H., Pandey-Pommier, M., Pandey, V.N., Pekal, R., Pizzo, R., Reich, W., Rothkaehl, H., Röttgering, H.J.A., Rowlinson, A., Schwarz, D.J., Shulevski, A., Sluman, J., Smirnov, O., Soida, M., Tagger, M., Toribio, M.C., van Ardenne, A., Wijers, R.A.M.J., van Weeren, R.J., Wucknitz, O., Zarka, P., and Zucca, P. Nature 568, 360 (2019)

LOFAR Observations of 4C+19.44: On the Discovery of Low-frequency Spectral Curvature in Relativistic Jet Knots. Harris, D.E., Moldón, J., Oonk, J.R.R., Massaro, F., Paggi, A., Deller, A., Godfrey, L., Morganti, R., and Jorstad, S.G. ApJ 873, 21 (2019)

Radio observations of the merging galaxy cluster Abell 520. Hoang, D.N., Shimwell, T.W., van Weeren, R.J., Brunetti, G., Röttgering, H.J.A., Andrade-Santos, F., Botteon, A., Brüggen, M., Cassano, R., Drabent, A., de Gasperin, F., Hoeft, M., Intema, H.T., Rafferty, D.A., Shweta, A., and Stroe, A. A&A 622, A20 (2019)

Characterizing the radio emission from the binary galaxy cluster merger Abell 2146. Hoang, D.N., Shimwell, T.W., van Weeren, R.J., Röttgering, H.J.A., Botteon, A., Brunetti, G., Brüggen, M., Cassano, R., Hlavacek-Larrondo, J., Gendron-Marsolais, M.-L., and Stroe, A. A&A 622, A21 (2019)

Constraints on the low frequency spectrum of FRB 121102. Houben, L.J.M., Spitler, L.G., ter Veen, S., Rachen, J.P., Falcke, H., and Kramer, M. A&A 623, A42 (2019)

Radio detection of extensive air showers - Measuring the properties of cosmic rays with the radio technique at LOFAR and the Pierre Auger Observatory. Hörandel, J.R. Nuclear and Particle Physics Proceedings 306, 108 (2019)

CHANG-ES: XVIII—The CHANG-ES Survey and Selected Results. Irwin, J., Damas-Segovia, A., Krause, M., Miskolczi, A., Li, J., Stein, Y., English, J., Henriksen, R., Beck, R., Wiegert, T., and Dettmar, R.-J. Galaxies 7, 42 (2019)

LOFAR measures the hotspot advance speed of the high-redshift blazar S5 0836+710. Kappes, A., Perucho, M., Kadler, M., Burd, P.R., Vega-García, L., and Brüggen, M. A&A 631, A49 (2019)

Probing gaseous halos of galaxies with radio jets. Krause, M.G.H., Hardcastle, M.J., and Shabala, S.S. A&A 627, A113 (2019)

Multi-frequency Scatter-broadening Evolution of Pulsars. II. Scatter-broadening of Nearby Pulsars. Krishnakumar, M.A., Maan, Y., Joshi, B.C., and Manoharan, P.K. ApJ 878, 130 (2019)

AARTFAAC flux density calibration and Northern hemisphere catalogue at 60 MHz. Kuiack, M., Huizinga, F., Molenaar, G., Prasad, P., Rowlinson, A., and Wijers, R.A.M.J. MNRAS 482, 2502 (2019)

First imaging spectroscopy observations of solar drift pair bursts. Kuznetsov, A.A. and Kontar, E.P. A&A 631, L7 (2019)

Morphological classification of radio galaxies: capsule networks versus convolutional neural networks. Lukic, V., Brüggen, M., Mingo, B., Croston, J.H., Kasieczka, G., and Best, P.N. MNRAS 487, 1729 (2019)

LoTSS DR1: Double-double radio galaxies in the HETDEX field. Mahatma, V.H., Hardcastle, M.J., Williams, W.L., Best, P.N., Croston, J.H., Duncan, K., Mingo, B., Morganti, R., Brienza, M., Cochrane, R.K., Gürkan, G., Harwood, J.J., Jarvis, M.J., Jamrozy, M., Jurlin, N., Morabito, L.K., Röttgering, H.J.A., Sabater, J., Shimwell, T.W., Smith, D.J.B., Shulevski, A., and Tasse, C. A&A 622, A13 (2019)

Ultra-steep spectrum emission in the merging galaxy cluster Abell 1914. Mandal, S., Intema, H.T., Shimwell, T.W., van Weeren, R.J., Botteon, A., Röttgering, H.J.A., Hoang, D.N., Brunetti, G., de Gasperin, F., Giacintucci, S., Hoekstra, H., Stroe, A., Brüggen, M., Cassano, R., Shulevski, A., Drabent, A., and Rafferty, D. A&A 622, A22 (2019)

Revisiting the Fanaroff-Riley dichotomy and radio-galaxy morphology with the LOFAR Two- Metre Sky Survey (LoTSS). Mingo, B., Croston, J.H., Hardcastle, M.J., Best, P.N., Duncan, K.J., Morganti, R., Rottgering, H.J.A., Sabater, J., Shimwell, T.W., Williams, W.L., Brienza, M., Gurkan, G., Mahatma, V.H., Morabito, L.K., Prandoni, I., Bondi, M., Ineson, J., and Mooney, S. MNRAS 488, 2701 (2019)

Blazars in the LOFAR Two-Metre Sky Survey first data release. Mooney, S., Quinn, J., Callingham, J.R., Morganti, R., Duncan, K., Morabito, L.K., Best, P.N., Gürkan, G., Hardcastle, M.J., Prandoni, I., Röttgering, H.J.A., Sabater, J., Shimwell, T.W., Shulevski, A., Tasse, C., and Williams, W.L. A&A 622, A14 (2019)

The origin of radio emission in broad absorption line quasars: Results from the LOFAR Two- metre Sky Survey. Morabito, L.K., Matthews, J.H., Best, P.N., Gürkan, G., Jarvis, M.J., Prandoni, I., Duncan, K.J., Hardcastle, M.J., Kunert-Bajraszewska, M., Mechev, A.P., Mooney, S., Sabater, J., Röttgering, H.J.A., Shimwell, T.W., Smith, D.J.B., Tasse, C., and Williams, W.L. A&A 622, A15 (2019)

Multiple regions of shock-accelerated particles during a solar coronal mass ejection. Morosan, D.E., Carley, E.P., Hayes, L.A., Murray, S.A., Zucca, P., Fallows, R.A., McCauley, J., Kilpua, E.K.J., Mann, G., Vocks, C., and Gallagher, P.T. Nature Astronomy 3, 452 (2019)

Detection and Timing of Gamma-Ray Pulsations from the 707 Hz Pulsar J0952-0607. Nieder, L., Clark, C.J., Bassa, C.G., Wu, J., Singh, A., Donner, J.Y., Allen, B., Breton, R.P., Dhillon, V.S., Eggenstein, H.-B., Hessels, J.W.T., Kennedy, M.R., Kerr, M., Littlefair, S., Marsh, T.R., Mata Sánchez, D., Papa, M.A., Ray, P.S., Steltner, B., and Verbiest, J.P.W. ApJ 883, 42 (2019)

The impact of interference excision on 21-cm epoch of reionization power spectrum analyses. Offringa, A.R., Mertens, F., and Koopmans, L.V.E. MNRAS 484, 2866 (2019)

Long-term variability of a black widow's eclipses - A decade of PSR J2051-0827. Polzin, E.J., Breton, R.P., Stappers, B.W., Bhattacharyya, B., Janssen, G.H., Osłowski, S., Roberts, M.S.E., and Sobey, C. MNRAS 490, 889 (2019)

Testing the accuracy of the ionospheric Faraday rotation corrections through LOFAR observations of bright northern pulsars. Porayko, N.K., Noutsos, A., Tiburzi, C., Verbiest, J.P.W., Horneffer, A., Künsemöller, J., Osłowski, S., Kramer, M., Schnitzeler, D.H.F.M., Anderson, J.M., Brüggen, M., Grießmeier, J.-M., Hoeft, M., Schwarz, D.J., Serylak, M., and Wucknitz, O. MNRAS 483, 4100 (2019)

LOFAR early-time search for coherent radio emission from GRB 180706A. Rowlinson, A., Gourdji, K., van der Meulen, K., Meyers, Z.S., Shimwell, T.W., ter Veen, S., Wijers, R.A.M.J., Kuiack, M.J., Shulevski, A., Broderick, J.W., van der Horst, A.J., Tasse, C., Hardcastle, M.J., Mechev, A.P., and Williams, W.L. MNRAS 490, 3483 (2019)

Identifying transient and variable sources in radio images. Rowlinson, A., Stewart, A.J., Broderick, J.W., Swinbank, J.D., Wijers, R.A.M.J., Carbone, D., Cendes, Y., Fender, R., van der Horst, A., Molenaar, G., Scheers, B., Staley, T., Farrell, S., Grießmeier, J.-M., Bell, M., Eislöffel, J., Law, C.J., van Leeuwen, J., and Zarka, P. Astron. Comput. 27, 111 (2019)

The LoTSS view of radio AGN in the local Universe. The most massive galaxies are always switched on. Sabater, J., Best, P.N., Hardcastle, M.J., Shimwell, T.W., Tasse, C., Williams, W.L., Brüggen, M., Cochrane, R.K., Croston, J.H., de Gasperin, F., Duncan, K.J., Gürkan, G., Mechev, A.P., Morabito, L.K., Prandoni, I., Röttgering, H.J.A., Smith, D.J.B., Harwood, J.J., Mingo, B., Mooney, S., and Saxena, A. A&A 622, A17 (2019)

Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A. Salas, P., Oonk, J.B.R., Emig, K.L., Pabst, C., Toribio, M.C., Röttgering, H.J.A., and Tielens, A.G.G.M. A&A 626, A70 (2019)

The LOFAR Tied-Array All-Sky Survey (LOTAAS): Survey overview and initial pulsar discoveries. Sanidas, S., Cooper, S., Bassa, C.G., Hessels, J.W.T., Kondratiev, V.I., Michilli, D., Stappers, B.W., Tan, C.M., van Leeuwen, J., Cerrigone, L., Fallows, R.A., Iacobelli, M., Orrú, E., Pizzo, R.F., Shulevski, A., Toribio, M.C., ter Veen, S., Zucca, P., Bondonneau, L., Grießmeier, J.-M., Karastergiou, A., Kramer, M., and Sobey, C. A&A 626, A104 (2019)

A LOFAR study of non-merging massive galaxy clusters. Savini, F., Bonafede, A., Brüggen, M., Rafferty, D., Shimwell, T., Botteon, A., Brunetti, G., Intema, H., Wilber, A., Cassano, R., Vazza, F., van Weeren, R., Cuciti, V., De Gasperin, F., Röttgering, H., Sommer, M., Bîrzan, L., and Drabent, A. A&A 622, A24 (2019)

Low-frequency Faraday rotation measures towards pulsars using LOFAR: probing the 3D Galactic halo magnetic field. Sobey, C., Bilous, A.V., Grießmeier, J.-M., Hessels, J.W.T., Karastergiou, A., Keane, E.F., Kondratiev, V.I., Kramer, M., Michilli, D., Noutsos, A., Pilia, M., Polzin, E.J., Stappers, B.W., Tan, C.M., van Leeuwen, J., Verbiest, J.P.W., Weltevrede, P., Heald, G., Alves, M.I.R., Carretti, E., Enßlin, T., Haverkorn, M., Iacobelli, M., Reich, W., and Van Eck, C. MNRAS 484, 3646 (2019)

LoTSS/HETDEX: Disentangling star formation and AGN activity in gravitationally lensed radio-quiet quasars. Stacey, H.R., McKean, J.P., Jackson, N.J., Best, P.N., Calistro Rivera, G., Callingham, J.R., Duncan, K.J., Gürkan, G., Hardcastle, M.J., Iacobelli, M., Mechev, A.P., Morabito, L.K., Prandoni, I., Röttgering, H.J.A., Sabater, J., Shimwell, T.W., Tasse, C., and Williams, W.L. A&A 622, A18 (2019)

CHANG-ES. XIX. Galaxy NGC 4013: a diffusion-dominated radio halo with plane-parallel disk and vertical halo magnetic fields. Stein, Y., Dettmar, R.-J., Weżgowiec, M., Irwin, J., Beck, R., Wiegert, T., Krause, M., Li, J.-T., Heesen, V., Miskolczi, A., MacDonald, S., and English, J. A&A 632, A13 (2019)

A LOFAR search for steep-spectrum pulsars in supernova remnants and pulsar wind nebulae. Straal, S.M. and van Leeuwen, J. A&A 623, A90 (2019)

The FRATS project: real-time searches for fast radio bursts and other fast transients with LOFAR at 135 MHz. ter Veen, S., Enriquez, J.E., Falcke, H., Rachen, J.P., van den Akker, M., Schellart, P., Bonardi, A., Breton, R.P., Broderick, J.W., Corbel, S., Corstanje, A., Eislöffel, J., Grießmeier, J.-M., Hörandel, J.R., van der Horst, A.J., Law, C.J., van Leeuwen, J., Nelles, A., Rossetto, L., Rowlinson, A., Winchen, T., and Zarka, P. A&A 621, A57 (2019)

The study of extended emission in a radio galaxy detected in the LOFAR Two-Metre Sky Survey. Thwala, S.A., Shafi, N., Colafrancesco, S., Govoni, F., and Murgia, M. MNRAS 485, 1938 (2019)

On the usefulness of existing solar wind models for pulsar timing corrections. Tiburzi, C., Verbiest, J.P.W., Shaifullah, G.M., Janssen, G.H., Anderson, J.M., Horneffer, A., Künsemöller, J., Osłowski, S., Donner, J.Y., Kramer, M., Kumari, A., Porayko, N.K., Zucca, P., Ciardi, B., Dettmar, R.-J., Grießmeier, J.-M., Hoeft, M., and Serylak, M. MNRAS 487, 394 (2019)

The search for radio emission from exoplanets using LOFAR beam-formed observations: Jupiter as an exoplanet. Turner, J.D., Grießmeier, J.-M., Zarka, P., and Vasylieva, I. A&A 624, A40 (2019)

Iron abundance distribution in the hot gas of merging galaxy clusters. Urdampilleta, I., Mernier, F., Kaastra, J.S., Simionescu, A., de Plaa, J., Kara, S., and Ercan, E.N. A&A 629, A31 (2019)

Diffuse polarized emission in the LOFAR Two-meter Sky Survey. Van Eck, C.L., Haverkorn, M., Alves, M.I.R., Beck, R., Best, P., Carretti, E., Chyży, K.T., Enßlin, T., Farnes, J.S., Ferrière, K., Heald, G., Iacobelli, M., Jelić, V., Reich, W., Röttgering, H.J.A., and Schnitzeler, D.H.F.M. A&A 623, A71 (2019)

Diffuse Radio Emission from Galaxy Clusters. van Weeren, R.J., de Gasperin, F., Akamatsu, H., Brüggen, M., Feretti, L., Kang, H., Stroe, A., and Zandanel, F. Space Sci. Rev. 215, 16 (2019)

A LOFAR-IRAS cross-match study: the far-infrared radio correlation and the 150 MHz luminosity as a star-formation rate tracer. Wang, L., Gao, F., Duncan, K.J., Williams, W.L., Rowan-Robinson, M., Sabater, J., Shimwell, T.W., Bonato, M., Calistro-Rivera, G., Chyży, K.T., Farrah, D., Gürkan, G., Hardcastle, M.J., McCheyne, I., Prandoni, I., Read, S.C., Röttgering, H.J.A., and Smith, D.J.B. A&A 631, A109 (2019)

Evolutionary phases of merging clusters as seen by LOFAR. Wilber, A., Brüggen, M., Bonafede, A., Rafferty, D., Shimwell, T.W., van Weeren, R.J., Akamatsu, H., Botteon, A., Savini, F., Intema, H., Heino, L., Cuciti, V., Cassano, R., Brunetti, G., Röttgering, H.J.A., and de Gasperin, F. A&A 622, A25 (2019)

The LOFAR Two-metre Sky Survey. III. First data release: Optical/infrared identifications and value-added catalogue. Williams, W.L., Hardcastle, M.J., Best, P.N., Sabater, J., Croston, J.H., Duncan, K.J., Shimwell, T.W., Röttgering, H.J.A., Nisbet, D., Gürkan, G., Alegre, L., Cochrane, R.K., Goyal, A., Hale, C.L., Jackson, N., Jamrozy, M., Kondapally, R., Kunert-Bajraszewska, M., Mahatma, V.H., Mingo, B., Morabito, L.K., Prandoni, I., Roskowinski, C., Shulevski, A., Smith, D.J.B., Tasse, C., Urquhart, S., Webster, B., White, G.J., Beswick, R.J., Callingham, J.R., Chyży, K.T., de Gasperin, F., Harwood, J.J., Hoeft, M., Iacobelli, M., McKean, J.P., Mechev, A.P., Miley, G.K., Schwarz, D.J., and van Weeren, R.J. A&A 622, A2 (2019)

On the Source Position and Duration of a Solar Type III Radio Burst Observed by LOFAR. Zhang, P., Yu, S., Kontar, E.P., and Wang, C. ApJ 885, 140 (2019)

Geoscience, Publications in refereed journals 2019, using the infrastructure at the Onsala site

Swedish authors (Geoscience)

A gravitational telescope deformation model for geodetic VLBI. Bergstrand, S.; Herbertsson, M.; Rieck, C.; Spetz, J.; Svantesson, C.-G.; Haas, R. J. Geod. 93, 669 (2019)

On the information content in linear horizontal delay gradients estimated from space geodesy observations. Elgered, G.; Ning, T.; Forkman P.; Haas, R. Atmospheric Measurement Techniques 12, 3805 (2019)

Atmospheric refraction and system stability investigations in short-baseline VLBI observations. Halsig, S.; Bertarini, A.; Haas, R.; Iddink, A.; Kodet, J.; Kronschnabl, G.; Neidhardt, A.; Nothnagel, A.‚ Plötz, C.; Schüler‚ T. J. Geod. 93, 593 (2019)

Fringe fitting and group delay determination for geodetic VLBI observations of DOR tones. Han, S. Nothnagel, a.; Zhang, Z.; Haas, R.; Zhang, Q. Advances in Space Research 63, 1754 (2019)

Nordic Antifouling Project – A follow-up of the MAMPEC workshop from 2017, Adjustment of the environment input parameters for more realistic values. Hanninen O. Nordic Working Papers, Nordic Council of Ministers (2019)

Investigating the gravitational stability of a radio telescope’s reference point using a terrestrial laser scanner: Case study at the Onsala Space Observatory 20-m radio telescope. Holst, C.; Nothnagel, A.; Haas, R.; Kuhlmann. ISPRS Journal of Photogrammetry and Remote Sensing 149, 67 (2019)

Realization of a multifrequency celestial reference frame through a combination of normal equation systems. Karbon, M.; Nothnagel, A. A&A 630, A101 (2019)

Impact of the terrestrial reference frame on the determination of the celestial reference frame. Karbon‚ M; Belda, S.; Nilsson, T. Geodesy and Geodynamics 10, 58 (2019)

Position determination of the Chang'e 3 lander with geodetic VLBI. Klopotek, G.; Hobiger, T.; Haas, R.; Jaron, F.; La Porta, L; Nothnagel, A. Earth, Planets and Space 71, 23 (2019)

Gravitational deformation of ring-focus antennas for VGOS: first investigations at the Onsala twin telescopes project. Lösler, M. Haas, R.; Eschelbach, C.; Greiwe, A. J. Geod. 93, 2069 (2019)

Earth Orientation Parameters from the CONT17 Campaign. Nilsson, T.; Balidakis, K.; Heinkelmann, R.; Schuh, H. Geophysica 54, 19 (2019)

A VLBI delay model for gravitational deformations of the Onsala 20 m radio telescope and the impact on its global coordinates. Nothnagel, A.; Holst, C.; Haas, R. J. Geod. 93, 2019 (2019)

Postglacial gravity change in Fennoscandia – three decades of repeated absolute gravity observations. Olsson, P.-A.; Kristian Breili, K.; Ophaug, V.; Steffen, H.; Bilker-Koivula, M.‚ Nielsen, E.; Oja, T.; Timmen, L. Geophysical Journal International 217, 1141 (2019)

The Potential for Unifying Global‐Scale Satellite Measurements of Ground Displacements using Radio Telescopes. Parker, A. L.; McCallum, L.; Featherstone, W. E.; McCallum, J.; Haas, R. Geophysical Research Letters 46, 11841 (2019)

Using a Superconducting Gravimeter in Support of Absolute Gravity Campaigning - A feasibility study. Scherneck, H.-G.‚ Rajner, M. Geophysica 54, 117 (2019)

Can We Measure Sea Level With a Tablet Computer?. Strandberg, J.‚ Haas, R. IEEE Geoscience and Remote Sensing Letters (2019)

Real-time sea-level monitoring using Kalman filtering of GNSS-R data. Strandberg, J.; Hobiger, T.; Haas, R. GPS Solutions 23, 61 (2019)

International authors (Geoscience)

Modelagem dos Efeitos Geodinâmicos que afetam as Medições Maregráficas e GNSS. Albarici, F. L.; Guimarães, G. Do N.‚ Trabanco, J. L. A.; Santos, M. Revista Brasileira de Cartografia 71, 75 (2019)

Combined precise orbit determination of GPS and GLONASS with ambiguity resolution. An, X.; Meng, X.; Chen, H.; Jiang, W.; Xi, R.; Chen, Q. J. Geod. 93, 2585 (2019)

The IERS EOP 14C04 solution for Earth orientation parameters consistent with ITRF 2014. Bizouard, C.; Lambert, S.; Gattano, C.; Becker, O.; Richard, J.-Y. J. Geod. 93, 621 (2019)

Consistency and representativeness of integrated water vapour from ground-based GPS observations and ERA-Interim reanalysis. Bock, O.; Parracho, A. C. Atmos. Chem. Phys. 19, 9453 (2019)

Earth rotation variations observed by VLBI and the Wettzell “G” ring laser during the CONT17 campaign. Böhm, S.; Schartner, M.; Gebauer, A.; Klügel, T.; Schreiber, U. Schüler, T. Adv. Geosci. 50, 9 (2019)

Analyses of celestial pole offsets with VLBI, LLR, and optical observations. Cheng, Y. -T.; Liu, J. -C.; Zhu, Z. A&A 627, A81 (2019)

Analysis of the Principal Constituents of Solid Earth Tides Estimated With Gravimetric and GNSS Data in Manaus and Brasília. de Abreu, M. A.; Marotta, G. S.; Ferreira, L.; Blitzkow, D.; de Matos, A. C. O. C.; Galera Monico J. F. Brazilian Journal of Geophysics 37, 11 (2019)

Multi-GNSS real-time clock estimation using sequential least square adjustment with online quality control. Fu, W.; Huang, G.; Zhang, Q.; Gu, S.; Ge, M.; Schuh, H. J. Geod. 93, 963 (2019)

A modified phase clock/bias model to improve PPP ambiguity resolution at Wuhan University. Geng, J.; Chen, X.; Pan, Y.; Zhao, Q. J. Geod. 93, 2053 (2019)

On the impact of local ties on the datum realization of global terrestrial reference frames. Glaser, S.; König, R.; Neumayer, K. H.; Nilsson, T.; Heinkelmann, R.; Flechtner, F.; Schuh, H. J. Geod. 93, 655 (2019)

Postseismic deformation following the 2 July 2013 Mw 6.1 Aceh, Indonesia, earthquake estimated using GPS data. Gunawan, E., Widiyantoro, S., Zulfakriza, Meilano, I., and Pratama, C. Journal of Asian Earth Sciences 177, 146 (2019)

Helmert-VCE-aided fast-WTLS approach for global ionospheric VTEC modelling using data from GNSS, satellite altimetry and radio occultation. Hu, A.; Li, Z.; Carter, B.; Wu, S.; Wang, X.; Norman, R; Zhang, K. J. Geod. 93, 877 (2019)

Sensitivity of GNSS tropospheric gradients to processing options. Kacmarík, M.; Douša, J.; Zus, F.; Václavovic, P.; Balidakis, K.; Dick, G.; Wickert, J. Ann. Geophys. 37, 429 (2019)

Geocenter motion time series derived from GRACE GPS and LAGEOS observations. Kang, Z.; Tapley, B.; Chen, J.; Ries, J.; Bettadpur, S. J. Geod. 93, 1931 (2019)

Reconstruction of 2D/3D ionospheric disturbances in high-latitude and arctic regions during a geomagnetic storm using GNSS carrier TEC: a case study of the 2015 great storm. Kong, J.; Fei Li, F.; Yao, Y.; Wang, Z.; Peng, W.; Zhang, Q. J. Geod. 93, 1529 (2019)

Unanticipated Uses of the Global Positioning System. Larson, K.M. Annual Review of Earth and Planetary Sciences 47, 19 (2019)

Single‑frequency PPP models: analytical and numerical comparison. Li, B.; Zang, N.; Ge, H.; Shen, Y. J. Geod. 93, 2499 (2019)

Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning. Li, X.; Chen, X.; Ge, M.; Schuh, H. J. Geod. 93, 45 (2019)

LEO constellation-augmented multi-GNSS for rapid PPP convergence. Li, X.; Ma, F.; Li, X.; Lv, H.; Bian, L.; Jiang, Z.; Zhang, X. J. Geod. 93, 749 (2019)

Real-time estimation of multi-GNSS integer recovery clock with undifferenced ambiguity resolution. Li, X.; Xiong, Y.; Yuan, Y.; Wu, J.; Li, X.; Zhang, K.; Huang, J. J. Geod. 93, 2515 (2019)

Triple-frequency PPP ambiguity resolution with multi-constellation GNSS: BDS and Galileo. Li, X.; Li, X.; Liu, G.; Feng, G.; Yuan, Y.; Zhang, K.; Ren, X. J. Geod. 93, 1105 (2019)

An efficient undifferenced method for estimating multi-GNSS high-rate clock corrections with data streams in real time. Liu, T.; Zhang, B.; Yuan, Y.; Zha, J.; Zhao, C. J. Geod. 93, 1435 (2019)

Galactocentric acceleration in VLBI analysis - Findings of IVS WG8. MacMillan, D. S.; Fey, A.; Gipson, J. M.; Gordon, D.; Jacobs, C. S.; Krásná, H.; Lambert, S. B.; Malkin, Z.; Titov, O.; Wang, G.; Xu, M. H. A&A 630, A93 (2019)

Correcting surface loading at the observation level: impact on global GNSS and VLBI station networks. Männel, B.; Dobslaw, H.; Dill, R.; Glaser, S.; Balidakis, K.; Thomas, M.; Schuh, H. J. Geod. 93, 2003 (2019)

Mechanism of error propagation from the subdaily Universal Time model into the celestial pole offsets estimated by VLBI. Panafidina, N.; Hugentobler, U., Krásná, H.; Schmid, R.; Seitz, M. Advances in Space Research 63, 51 (2019)

GPS inter-frequency clock bias estimation for both uncombined and ionospheric-free combined triple-frequency precise point positioning. Pan, L.; Zhang, X.; Guo, F.; Liu, J. J. Geod. 93, 473 (2019)

Between-satellite single-difference integer ambiguity resolution in GPS/GNSS network solutions. Ruan, R.; Wei, Z. J. Geod. 93, 1367 (2019)

Vertical motion of Phuket Island (1994–2018) due to the Sumatra-Andaman mega-thrust earthquake cycle: impact on sea-level and consequences for coral reefs. Simons, W. J. F.; Naeije, M. C.; Brown, B. E.; Niemnil, S.; Pradit, S.; Thongtham, N.; Mustafar, M. A.; Towatana, P.‚ Darnsawasdi, R.; Yucharoen, M.; Visser, P. N. A. M. Marine Geology 414, 92 (2019)

Evidence of daily hydrological loading in GPS time series over Europe. Springer, A.; Karegar, M. A.; Kusche, J.; Keune, J.; Kurtz, W.; Kollet, S. J. Geod. 93, 2145 (2019)

Horizontal Intraplate Velocity Field Model for the Territory of Bulgaria Derived From GNSS Solution. Tsanovski, Y.; Danchev, T. International Multidisciplinary Scientific GeoConference: SGEM 19, 165 (2019)

The realization and evaluation of mixed GPS/BDS PPP ambiguity resolution. Yao, Y.; Peng, W.; Xu, C.; Shi, J.; Cheng, S.; Ouyang, C. J. Geod. 93, 1283 (2019)

Multipath extraction and mitigation for high-rate multi-GNSS precise point positioning. Zheng, K.; Zhang, X.; Li, P.; Li, X.; Ge, M.; Guo, F.; Sang, J.; Schuh, H. J. Geod. 93, 2037 (2019)

Onsala 20 m telescope, single-dish observations, publications in refereed journals 2019

Swedish authors (OSO 20 m)

International authors (OSO 20 m)

NH3 observations of the S235 star-forming region: Dense gas in inter-core bridges. Burns, R.A., Handa, T., Omodaka, T., Sobolev, A.M., Kirsanova, M.S., Nagayama, T., Chibueze, J.O., Kohno, M., Nakano, M., Sunada, K., and Ladeyschikov, D.A. PASJ 71, 91 (2019)

A multi-molecular line study of the star-forming globule CB88-230. Brand, J., Wouterloot, J.G.A., Codella, C., Massi, F., and Giannetti, A. A&A 628, A98 (2019)

Observational Signatures of End-dominated Collapse in the S242 Filamentary Structure. Dewangan, L.K., Pirogov, L.E., Ryabukhina, O.L., Ojha, D.K., and Zinchenko, I. ApJ 877, 1 (2019)

Technical publications in refereed journals and conference proceedings 2019, about, e.g., receiver development, by OSO staff

Improved bandwidth of a 2 THz hot-electron bolometer heterodyne mixer fabricated on sapphire with a GaN buffer layer. Antipov, S., Trifonov, A., Krause, S., Meledin, D., Kaurova, N., Rudzinski, M., Desmaris, V., Belitsky, V., Goltsman, G. Supercond. Sci. Technol. 32, 075003 (2019)

Optimization and Realization of Quadruple-ridge Flared Horn with New Spline-defined Profiles as a High-efficiency Feed over 4.6–24 GHz. Dong, B., Yang, J., Dahlström, J., Flygare, J., Pantaleev, M., Billade, B. IEEE Transactions on Antennas and Propagation 67, 585 (2019)

Design of Octave-bandwidth Phased Array Feed for Large Radio Telescope . Fan, J., Yang, J., Yan, Y., Zhu, K., Jiang, P., Cao, H., Ma, J., Li, B., Pantaleev, M. 13th European Conference on Antennas and Propagation (EuCAP) (2019)

Wideband single pixel feed system over 4.6-24 GHz for the Square Kilometre Array. Flygare J., Dong B., Yang J., Helldner, L. , Dahlgren, M. , Chengjin, J. , Pantaleev, M. , Hovey, G. , Conway, J. Proceedings of the 2019 21st International Conference on Electromagnetics in Advanced Applications, ICEAA 2019, 630 (2019)

Sensitivity simulation and measurement of the SKA Band 1 wideband feed package on MeerKAT. Flygare, J., Peens-Hough, A., Helldner, L., Dahlgren, M., Smit, G., Kotze, P. 13th European Conference on Antennas and Propagation (EuCAP) (2019)

Interface Layers of Niobium Nitride Thin Films. Lubenchenko A.V., Iachuk, V.A., Krause, S., Pavolotsky, A.B., Ivanov, D.A., Lubenchenko, O.I. and Pavlov, O.N. J. Phys.: Conf. Ser. 1410, 01212 (2019)

A 1MM SIS Receiver Utilizing Different Intermediate Frequency (IF) Configurations. Meledin, D., V. Desmaris, E. Sundin, A. Pavolotsky, M. Fredrixon, I. Lapkin, M. Strandberg, A. Ermakov, J.-D., Gallego, I. Lopez-Fernandez, C. Diaz, and V. Belitsky. ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book, 164 (2019)

The Origins Space Telescope and the HEterodyne Receiver for Origins (HERO). Wiedner, M. C., A. Baryshev, V. Belitsky, V. Desmaris, A. DiGiorgio, J.-D. Gallego, M. Gerin, P. Goldsmith, F. Helmich, W. Jellema, A. Laurens, I. Mehdi, C. Risacher, HERO technical team, HERO science team, the heterodyne receiver roadmap team, A. Cooray, M. Meixner, and the Origins Study Team. ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book, 204 (2019)

Key numbers (nyckeltal)

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

Infrastrukturens namn: OSO Diarienummer: 2017‐00648 Respondent (namn): John Conway Respondent (epost): [email protected] Respondent (telefon): 031‐772 5503 Avser år: 2019

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

1 Anställda vid infrastrukturen Förklaringar till tabell 2, 3 och 4: 1.1 Enskilda individer Totalt 54 ALMA: Tabell 2: Projekt med en nordisk PI. Cycle 6 (observationer oktober 2018 ‐ september 2019) Astro user support / ARCnode (Modul 2) 6 Tabell 3: Nordiska användare på alla projekt (även projekt med icke‐nordisk PI). Cycle 6. 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 P103 och P104 (observationer 2019). LOFAR (Modul 5) 2 Astronomisk VLBI: Alla proposaler inskickade 2019. Alla observationer utförda 2019. Geovetenskap (Modul 6) 13 LOFAR: Alla projekt i Cycle 11 och 12 (observationer november 2018 ‐ november 2019) Utveckling av mm‐mottagare (Modul 8) 8 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) 4 Övriga tjänster (Modul 10) 5 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 34,0 Gråmarkerade fält är inte aktuella för OSO. ALMA / ARCnode (Modul 2) 3,3 APEX svensk tid (Modul 3) 3,1 Astronomisk VLBI (Modul 4) 3,2 LOFAR (Modul 5) 0,8 Geovetenskap (Modul 6) 5,0 Utveckling av mm‐mottagare (Modul 8) 6,5 Utveckling av cm‐mottagare (Modul 9) 6,2 Ledning (Modul 1) 1,9 Övriga tjänster (Modul 10) 4,0

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 250 165 85 250 165 85 59 7 184 ALMA (projekt med nordisk PI) 92 54 38 92 54 38 46 6 40 APEX svensk tid 33 22 11 33 22 11 9 1 23 Astronomisk VLBI 75 55 20 75 55 20 2 0 73 LOFAR 50 34 16 50 34 16 2 0 48 2.2 Genomförda projekt Totalt 86 59 27 86 59 27 16 3 67 ALMA (projekt med nordisk PI) 19 12 7 19 12 7 10 2 7 APEX svensk tid 17 11 6 17 11 6 4 1 12 Astronomisk VLBI 22 15 7 22 15 7 1 0 21 LOFAR 28 21 7 28 21 7 1 0 27 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 861 630 231 861 630 231 46 39 776 ALMA (nordiska användare, alla projekt) 143 103 40 143 103 40 35 36 72 APEX svensk tid 116 73 43 116 73 43 20 2 94 Astronomisk VLBI 421 328 93 421 328 93 9 5 407 LOFAR 287 203 84 287 203 84 6 1 280 3.2 Genomförda projekt Totalt 495 356 139 495 356 139 31 14 450 ALMA (nordiska användare, alla projekt) 65 46 19 65 46 19 21 12 32 APEX svensk tid 87 51 36 87 51 36 12 1 74 Astronomisk VLBI 149 118 31 149 118 31 4 1 144 LOFAR 235 171 64 235 171 64 4 1 230

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) 19 19 12 7 APEX svensk tid (h) 439 439 231 208 Astronomisk VLBI (h) 1112 1112 1028 84 LOFAR (h) 5161 5161 4580 581 Geodetisk VLBI (h) 1768 1768 n/a n/a

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