The Messenger

No. 167 – March 2017 galaxy survey z SN 1987A 30th anniversary 1987A SN Archive Science ALMA The 5 Band ALMA high- VANDELS Telescopes and Instrumentation DOI: doi.org/10.18727/0722-6691/5000

The ALMA Science Archive

Felix Stoehr1 Figure 1. Fraction of 1 ALMA publications that Alisdair Manning 20 % PI + archival 1 make use of either only Christophe Moins archival archival ALMA data 2 Dustin Jenkins (green) or both ALMA PI Mark Lacy3 and archival data at the Stéphane Leon4 15 % same time (blue). 2013 5 was the first year when Erik Muller ALMA PI data became 5 Kouichiro Nakanishi public and thus the first 6 archival publications Brenda Matthews 10 % Séverin Gaudet2 appear in 2014. Eric Murphy3 Kyoko Ashitagawa5 Akiko Kawamura5 5%

1 ESO 0% 2 Canadian Astronomical Data Centre (CADC), National Research Council of 2012 2013 2014 2015 2016 Canada, Victoria, Canada 3 National Radio Astronomy Observatory (NRAO), Charlottesville, USA proposal process, one of the main pur- in the world at that time. As astronomy 4 Joint ALMA Observatory (JAO), Vitacura, poses of a science archive is indeed to will inevitably transform into a science Santiago, Chile enable independent research. where the largest fraction of observed 5 National Astronomical Observatory of pixels will never be looked at by a human, Japan (NAOJ), National Institutes of For only a very small fraction (of the machine-aided analysis will inevitably Natural Sciences, Tokyo, Japan order 1–3 %) of the total yearly opera- increase in importance. This approach 6 National Research Council of Canada, tional cost of a facility, substantial addi- includes scientific pre-analysis (for exam- Victoria, Canada tional scientific progress can be obtained ple, the ALMA Data MIning Toolkit, through public provision of a science ADMIT: Teuben et al., 2015), remote visu- archive. This is, for example, true in the alisation (for example, the Cube Analysis Science archives help to maximise case of the Hubble Space Telescope and Rendering Tool for Astronomy, the scientific return of astronomical (HST), where publications making use of CARTA: Rosolowsky et al., 2015) and facilities. After placing science archives archival data have by now outnumbered remote analysis (code-to-data), as well into a slightly larger context, we the publications of PI observations by as analysis based on machine learning. describe the current status and capa the proposing teams. Romaniello et al. In particular, deep learning is currently bilities of the ALMA Science Archive. (2016) also report the growth of an ESO witnessing an epochal change and dra- We present the design principles and archive community, where almost 30 % matic new possibilities can be expected technology employed for three main of users downloading data from the Sci- over the next few years. Successful contexts: query; result set display; and ence Archive Facility (SAF) have never approaches, like automatic caption gen- data download. A summary of the been PI or co-investigator of an ESO pro- eration for images2 and human-quality ALMA data flow is also presented as posal. For the still very young Atacama astronomical object classification are access statistics to date. Large Millimeter/submillimeter Array (Dieleman et al., 2015), give an indication (ALMA) facility and its ALMA Science of the future prospects in this area. A Archive1, we can report a rapidly increas- powerful well-characterised science Introduction ing fraction of publications making use archive is the basis of such data-mining. of archival data (Figure 1), already reach- The overall success of an astronomical ing 16 % (or 27 % including publications Depending on the nature of the project facility is measured by the quality and from Science Verification data) in 2016 and its goals, and notwithstanding the quantity of science produced by its com- (see also Stoehr et al., 2015). remark about the small operational costs munity. By helping the principal inves of archives, the fraction of the total cost tigators (PIs) and archival researchers of The requirement that data be well that astronomical facilities spend on the facility to easily discover, explore and described and easy to discover through data management is expected to slowly download the data they need, a science science archives can be expected to increase. An extreme showcase of this archive helps to maximise the scientific grow rapidly in the future, as the amount evolution, admittedly in a different con- return and thus to increase the success of data increases exponentially. For text, is the Large Synoptic Survey Tele- of the facility. In addition to the delivery of example, we estimate that the fully opera- scope (LSST), where 52 % of the total data to PIs, provision of data-persistence tional Square Kilometre Array (SKA) will survey cost of $1.25 billion is expected for independent verification of scientific deliver around 200 TB per year of sci- to be spent on data management3. results and duplication checking in the ence images for every active astronomer

2 The Messenger 167 – March 2017 Figure 2. Query interface of the ALMA Science Archive with grouped keywords displaying self-opening input fields, unobtrusive tooltip help and the three different views for selection.

Querying cations and proposals. Currently 31 input – show all public, but unpublished, fields are available, of which 14 are observations. This enables the ALMA Searching astronomical data via search numerical. For the input fields, a variety project to survey non-publishing PIs interfaces differs greatly from standard of operators can be used (equals, like, and to investigate the reasons why they web searches, such as that provided by or, <, >, range, not, …). The query is could not publish (Stoehr et al., 2016); Google. Whereas the latter solve the completely unscoped, that is we do not – show all publications making use of problem “find words in a collection of text require users to first query by position or full-polarisation data; documents”, searches in astronomical object name, or even require any con- – show the proposals, data from which archives are inherently multi-dimensional straint at all. Hitting search without con- were used in publications having and many parameters are numerical straints will return the full holdings. This “molecular hydrogen” in the publication rather than textual. In that sense, astro- choice also has the positive side-effect abstract; nomical search engines are closer to that the multi-parameter search capability – show all publications making use of product-finder search engines4. Moreo- is automatically extended to all the more data from the programme “Discs ver, the target audience of astronomical rarely used columns in the results table around high-mass stars”; searches is extremely homogeneous which do not show up on the query form, – show all observations of active galaxies and highly educated, as the vast majority but for which we still provide a sub-filtering reaching line sensitivities of 1 mJy/beam of the users will hold degrees in astron- capability on the results page, like, for at 10 km s–1 resolution or continuum omy or physics. example, whether or not an observation sensitivities of 0.1 mJy/beam. is a mosaic or which antenna types were With this consideration in mind, our main employed. The user can choose to dis- Maximally physical query design principles in the ALMA Science play the results of any query in a view Great efforts have been made to allow Archive are: access to the full parameter where one row corresponds to one constraints to be placed on as many space; a maximally physical query; and, observation, or to one project, or even to physical parameters as possible, accord- at the same time, minimal interaction one publication. Given the homogeneous ing to the main properties a photon cost. We consider each of these princi- and educated audience, we intentionally carries: position, energy, time and polari- ples in turn. chose not to provide an additional “basic” sation; see also Stoehr et al. (2014). interface. Examples are the angular and spectral Full parameter space resolutions, the field of view, frequencies, In the ALMA Science Archive we provide This multi-dimensional unscoped inter- bandwidth and the largest angular scale. the capability to place query constraints face permits powerful queries to be exe- In addition, users can now also query simultaneously on observations, publi cuted. For example: on the estimated sensitivity expected to

The Messenger 167 – March 2017 3 Telescopes and Instrumentation Stoehr F. et al., The ALMA Science Archive

Figure 3. Results page for the ALMA Science Archive featuring foot- print display on Aladin- Lite and the results table with sub-filtering, sorting, adding/removing of any of the 37 columns and the bookmarking/ exporting links.

be reached for line or continuum obser- ALMA archive context this means reduc- In contrast to the one-line interfaces of vations. This value, corresponding to the ing the cost of reading, identifying, as word-in-text searches, the knowledge limiting magnitude in optical observa- well as memorising, the structure and of the search space (“what constraints tions, is a particularly useful constraint. functionality of the interface. It also can be given”) on advanced interfaces is In addition, we capture the physical con- includes reducing the mouse travel dis- not trivially acquired by the users. There- tent of the observations from the users, tance and the number of mouse clicks, fore the first task of any such interface offering the scientific keywords specified as well as ensuring that users should must be to explain that search space. In when the proposal was written and the not be forced to leave the page during order to reduce the interaction cost of scientific categories, as well as allowing their interaction with the interface. A key this process, we visually group the con- searches through the titles and abstracts to reducing interaction cost is to only cepts, order them by importance within of the proposals and also publications provide the information to the users that the groups, remove everything that is making use of ALMA data. they need at a given moment during the unnecessary and make sure that the interaction with the interface (see also entire context fits onto the screens even Providing searches on physical concepts Stoehr et al., 2012 and Stoehr, 2017 in of small laptops. The interface is trimmed rather than observatory-specific jargon press) and to re-use the existing web for responses that are fast enough, so (for example, “angular resolution” rather knowledge and habits of users. that the relevant context still resides in than “array-configuration”) is especially the user’s short-term memory6, further important, as ALMA’s mission explicitly For the ALMA Science Archive interface lowering the interaction cost. includes enabling non-radio astronomers (Figure 2), these principles mean, for to use the facility. example, to open input fields only when needed, to close them unless a value Query results Minimal interaction cost has been entered, to place the buttons Although, as shown above, astronomical always at the same location on the The second step of every search is the searches are quite different from typical pages, to provide help directly on the exploration of the results to identify the web searches, wherever possible classi- page, to show information for each input assets in which the user is finally inter- cal web-design principles have been field unobtrusively in a tooltip when the ested. For the ALMA Science Archive we applied. The most important of those user is entering a value, and to have show the observations in their astronomi- principles is to reduce the interaction those tooltips contain clickable examples. cal context, using the observational foot- cost of the user to a minimum5. In the prints and the AladinLite7 (Bonnarel et al.,

4 The Messenger 167 – March 2017 2000; Boch & Fernique, 2014) sky view Figure 4. Fraction of the total amount of data (Figure 3). In addition to zooming and downloaded, shown by download tool. panning, this software package allows 67 % wget the user to select sky backgrounds of different wavelength regimes. The sky view is fully integrated with the results table.

The results table developed by ALMA 0% other features sorting and reordering of the col- 2% webstart umns, sub-filtering and change of units 4% astroquery on the fly, as well as addition or removal of any of the 37 currently available col- 5% Applet umns. For data still within their proprie- tary period, users can generate a calen- 5% curl dar event to notify them when those data become public. For each observation, 18 % Mozilla the number of related publications is displayed and a link takes the user to a list set to the minimum of the velocity reso ing environment. About two-thirds of the with the detailed description of those lutions of the child observations), some total amount of data retrieved from the publications, including links to the Astro- computations were more challenging ALMA archive is downloaded through nomical Data System (ADS8). The publi- (such as the average integration time per download scripts (Figure 4). cation information is curated by ESO, position in a mosaic with overlapping NRAO and NAOJ library staff (Grothkopf pointings, or the spectral window pattern In addition to the display on the web, & Meakins, 2015 and references therein). matching). An offspring of this develop- the results of the query can be exported Hovering over the project code (or bibli- ment is the computation of footprints as Virtual Observatory (VO) VOTable, ography code) brings up a window with shown on the sky view (Figure 3). comma separated values (CSV) or tab the title, author name and abstract of that separated values (TSV) files. Indeed full proposal or publication. programmatic access is supported for Data download querying as well as for download. This Large result sets are streamed from the functionality is used, for example, by the server to the user’s browser, so the first Once the desired assets are selected for community-developed software astro- results in the table are immediately visi- download, the user is brought to the query9 which provides full ALMA archive ble; the table, however, remains interac- ALMA Request Handler. Here the related access through Python. Besides being tive as more and more results are loaded files are listed and the user is enabled to good practice, programmatic access is in the background. The interface also download specific files or select files by crucial for interoperable archives and memorises its entire state so that the project, dataset or datatype. The names data-mining. query and result-table settings can be of the observation sets, as well as a list of bookmarked, or the corresponding link the names of the contained sources, are can be sent to a colleague. given for each dataset to facilitate the Technology selection process. This information is also As no complete set of imaged ALMA available in an auto-generated readme file The ALMA archive is at the centre of products is available, the ALMA Science which also lists the full data directory ALMA operations and all subsystems Archive query is based on the metadata names. read and write from and to this central of the raw data of the observations. location (see, Stoehr et al., 2014). The Those metadata, however, are only avail- As the sizes of ALMA datasets are sub- main archive is located in Santiago, Chile able at a sub-observation level. In past stantial, downloading in multiple parallel at the Joint ALMA Observatory (JAO) years, this has led to the effect that for a streams is a necessity. Depending on the and data are replicated from there to the single observation several result rows — user’s internet browser and operating three archives located at NRAO, NAOJ and for mosaics up to several hundred system, several download methods are and ESO, which distribute them to the rows — were returned to the users. Sub- offered. A download shell script, a Java users. Each site only holds a single copy stantial efforts were deployed over the applet, a Java webstart, and a page of each file and the sites serve as remote last two years to “collapse” these meta- containing the list of the files which then backups for each other. data into one row per observation by can be fed to a browser plugin download applying the same logic that the ALMA manager, are all available. Data are transferred over the network Pipeline would apply if it were to create with dedicated network links of typically imaging products from those raw data. The preferred download option is the 100 Mbit s–1 and are stored in the ESO- While computing some of the values of shell script, which additionally allows the developed storage system, the Next Gen- these collapsed rows was rather simple user to download the files to a different eration Archive System (NGAS: Wicenec (for example, the velocity resolution was computer, such as directly to a process- et al., 2001; Wicenec & Knudstrup, 2007).

The Messenger 167 – March 2017 5 Telescopes and Instrumentation Stoehr F. et al., The ALMA Science Archive

400 Figure 5. (Upper left) Cumulative data flow into the archive (green) and out of the archive (blue) in TB. 350 Outﬂow The outflow could only be measured after the ALMA Inﬂow Request Handler was put in place in 2013. To Febru- ary 2017, 386 TB have been delivered and 259 TB 300 downloaded. B)

(T 250 Figure 6. (Lower left) Time between the public avail- ability of data and their download. Data are down-

lume 200 loaded rapidly after they become public (12 months

vo for most data, 6 months for Director’s Discretionary 150 Time data) and remain heavily requested for a long

Data period. 100

50 years to improve the Results and Down- load contexts. These developments will 0 2012-012013-01 2014-012015-01 2016-01 include previews and access to individual files, progress in providing VO services, and integration of the two major related ALMA development programme tools, 4000 the data mining toolkit ADMIT and the visualisation package CARTA. 3500

3000 References ﬁles r 2500 Bonnarel, F. et al. 2000, A&A, 143, 33 ta Boch, T. & Fernique, P. 2014, ASPC, 485, 277

of Dieleman, S. et al. 2015, MNRAS, 450, 1441 2000 Grothkopf, U. & Meakins, S. 2015, ASP, 492, 63 Romaniello, M. et al. 2016, The Messenger, 163, 5

umber 1500 Rosolowsky, E. et al. 2015, ASPC, 495, 121 N Stoehr, F. et al. 2012, ASPC, 461, 697 1000 Stoehr, F. et al. 2014, SPIE, 9149, 914902 Stoehr, F. et al. 2015, The Messenger, 162, 30 Stoehr, F. et al. 2016, arXiv:1611.09625 500 Stoehr, F. 2017, ASPC, in preparation Teuben, P. et al. 2015, ASPC, 495, 305 0 Wicenec, A. et al. 2001, The Messenger, 106, 11 01020304050 Wicenec, A. & Knudstrup, J. 2007, The Messenger, Delay between data availabilty and download (months) 129, 27

The ALMA Science Archive is a single- have led to 588 publications so far. Cur- Links page web application deployed on rently the ALMA Science Archive is grow- 1 Apache Tomcat, built using Java, the ing by about 15 TB every month (see Fig- ALMA Science Archive: http://almascience.org/aq 2 Neural image caption generator: https://research. Spring framework, JQuery and Oracle ure 5). Data are downloaded quite quickly google.com/pubs/pub43274.html 12c. It is a deliverable of ESO to the for archival research after they become 3 LSST data management: http://euclidska.physics. ALMA project. We rely heavily on the public and remain of interest for a long ox.ac.uk/Euclid-SKA/160913/Tyson.pdf 4 OpenCADCTap10 software package, period (Figure 6). This is especially signifi- Product-finder search engines:http://www.idealo. co.uk/filter/3751/laptops.html?q=notebook which provides the VO layer on top of cant given that ALMA is still a very young 5 User interaction cost: https://www.nngroup.com/ the database holdings. The query inter- facility: the amount of data that is public articles/interaction-cost-definition/ face is a client to this VO layer using the for more than 40 months, for example, is 6 Web and short-term memory: http://www. Astronomical Data Query Language much smaller than the amount of data nngroup.com/articles/short-term-memory-and- web-usability 11 (ADQL ) as the interface language. that is public for more than 15 months. 7 AladinLite: http://aladin.u-strasbg.fr/AladinLite 8 ADS: https://ui.adsabs.harvard.edu/#search/ q=full%3A”ALMA”&sort=date%20desc%2C%20 Holdings and statistics Outlook bibcode%20desc 9 Python astroquery: https://astroquery.readthedocs.io/en/latest At the time of writing, the ALMA Science While the query functionality of the ALMA 10 OpenCADCTap package: Archive contains data from about 32 000 Science Archive can now compete with https://github.com/opencadc/tap 11 observations stored as 280 TB and dis- other astronomical archives, substantial ADQL: http://www.ivoa.net/documents/latest/ ADQL.html tributed over 18 million files. Those data work is still required over the next few

6 The Messenger 167 – March 2017 Telescopes and Instrumentation DOI: doi.org/10.18727/0722-6691/5001

ALMA Band 5 Science Verification

Liz Humphreys1 currently being produced by a consor- Andy Biggs1 tium led by Academia Sinica Institute Katharina Immer1 of Astronomy and Astrophysics [ASIAA] Robert Laing1 in Taiwan); and the lower portion of Hauyu Baobab Liu1 the 3 mm atmospheric transparency Gianni Marconi1 window (below 84 GHz), for which a Tony Mroczkowski1 new-technology, high-sensitivity receiver, Leonardo Testi1 dubbed Band 2+3 to cover the full Pavel Yagoubov1 67–116 GHz band, is currently being developed in Europe.

1 ESO ESO and several European partners (including Chalmers University in Sweden, the Science and Technology Facilities ALMA Band 5 (163–211 GHz) was Council [STFC] in the UK and the Univer- recently commissioned and Science sity of Chile) were awarded funding by Verification (SV) observations were the European Commission under the obtained in the latter half of 2016. A pri- EU’s Sixth Framework Programme (FP6) mary scientific focus of this band is the to develop prototypes of Band 5. A set of

H2O line at 183.3 GHz, which can be six prototype receivers was produced by observed around 15 % of the time when the Group for Advanced Receiver Devel- the precipitable water vapour is suffi- opment (GARD) at Chalmers University in ciently low (< 0.5 mm). Many more lines collaboration with the Rutherford Appleton are covered in Band 5 and can be Laboratory (United Kingdom) under an observed for over 70 % of the time on EU FP6 contract and delivered to ALMA Chajnantor, requiring similar restrictions in 2012 (Billade et al., 2012). ALMA to those for ALMA Bands 4 and 6. accepted the ESO proposal to outfit all Figure 1. An assembled ALMA Band 5 receiver 18 cartridge, shown courtesy of NOVA/GARD. Examples include the H2 O line at 66 antennas with Band 5 receivers in 203 GHz, some of the bright (3–2) lines 2012. of singly and doubly deuterated forms ments, most notably on the Atacama of formaldehyde, the (2–1) lines of The production of the revised and opti- Pathfinder EXperiment (APEX) telescope + + HCO , HCN, HNC, N2H and several of mised full complement of 73 Band 5 as part of the Swedish-ESO PI receiver their isotopologues. A young star- cartridges started in 2013, with produc- for APEX (SEPIA) project. The SEPIA forming region near the centre of the tion shared between GARD and the Band 5 receiver was commissioned at Milky Way, an evolved star also in our Nederlandse Onderzoekschool Voor APEX in 2016 and Immer et al. (2016) Galaxy, and a nearby ultraluminous Astronomie (NOVA), who were jointly describe the instrument and some of the infrared galaxy (ULIRG) were observed responsible for the production and the commissioning and SV observations. as part of the SV process and the data integration of the Cold Cartridge Assem- Other Band 5 pre-production cartridges are briefly described. The reduced data, bly of the receiver, and the National Radio will be installed on the Atacama Submil- along with imaged data products, are Astronomy Observatory (NRAO) in the limeter Telescope Experiment (ASTE) now public and demonstrate the power USA, who provided the Warm Cartridge on Chajnantor, and on the Large Latin of ALMA for high-resolution studies of Assembly. The receivers are dual polari- American Millimeter Array (LLAMA) in

H2O and other molecules in a variety of sation SIS (superconductor insulator Argentina. One is kept at ESO for public astronomical targets. superconductor) mixers used in a side- display. The installation of the production band-separating (2SB) configuration and Band 5 receivers started at ALMA during operated with all-reflective cold (< 4 K) 2015 and 2016 and the first fringes were One of the bands of the Atacama Large optics. The measured system tempera- obtained in July 2015. At the time of Millimeter/submillimeter Array (ALMA) ture of the production receiver is < 50 K writing 45 Band 5 cartridges have been that was not initially produced during over 80 % of the band (Belitsky et al., delivered to the ALMA project and 32 of construction of the observatory and was 2017), a figure significantly better than the these are integrated in ALMA Front Ends. not available when the array was officially original ALMA specifications for this inaugurated in 2013 was Band 5, cover- receiver band, and achieved thanks to Band 5 will be offered as a “standard ing the frequency range 163–211 GHz extensive optimisation work undertaken mode” in all available array configurations (1.9–1.4 mm). Band 5 was one of the at GARD following the production of the (including the ALMA Compact Array, three frequency ranges originally envi- six prototype receivers. Figure 1 shows ACA) in ALMA Cycle 5. Current plans are sioned for ALMA, but deferred from one of the Band 5 cartridges. for Band 5 to be available for science the construction project to the develop- observations starting in the second half ment programme. The other two are: Several of the six prototype Band 5 of the cycle (March 2018), following com- the 35–50 GHz frequency range (Band 1, receivers were installed in other instru- missioning of all the receivers.

The Messenger 167 – March 2017 7 Telescopes and Instrumentation Humphreys L. et al., ALMA Band 5 Science Verification

Band 5 Science Verification

ALMA Band 5 Science Verification (SV) observations took place from May to October 2016. In contrast to SV with Very Large Telescope (VLT) instruments, 0 where proposals are solicited from the 155 160 165 170175 community, a set of targets are selected by an SV team composed of ALMA staff and scientists with the goal of providing a full end-to-end test and scientific valida- tion of the new capability under operational conditions. The selection of targets 0 and modes for SV focuses on testing 175 180 185 190 195 challenging or novel calibration schemes to ensure smooth science operations. As per ALMA policy, the intention was to select targets with previous H2O observations in order to enable a careful compar-

ison with the ALMA results; in all cases Intensity (arbitrary unit) 0 the targets were also common to APEX 195 200 205 210 215 Frequency (GHz) SEPIA Band 5 observations. In the case of ALMA Band 5 SV, one extragalactic Figure 2. Superposition target with previously detected H O emis- 5000 au of ALMA (black) and 2 APEX (blue) spectra sion was selected — Arp 220, a prototypi- from part of the Band 5 cal luminous infrared galaxy — along with full spectral scan of the two Galactic targets: the molecular cloud Sgr B2 star-forming complex near the Galactic Centre, Sagit- region (from Baobab Lu, Katharina Immer, Anita tarius B2, selected for a full-band spectral 16ೀ Richards, Ana Lopez- scan; and the evolved supergiant star Sepulcre, Lydia Moser VY CMa, chosen to demonstrate the line ) and Daniel Tafoya). Spa-

000 tially extended emission

and continuum polarisation performance. 2 from bright lines is sup- (J H2O-3

c pressed in the interfero- Observations of the H O (3 –2 ) metric spectrum, while 2 1,3 2,0 De 183.3 GHz line are challenging even from the absorption features the very high site on Chajnantor, since the 20ೀ against the compact continuum sources and precipitable water vapour (PWV) is only the H2O maser lines are below 0.5 mm about 15 % of the time H O-2 well matched in the two H O-1 2 (~ 50 days per year). Figure 2 of Immer et 2 spectra. In the lower al. (2016) shows the atmospheric trans- panel, the estimated continuum emission mission through the 183.3 GHz H2O line image is shown overlaid –28°22 24 as a function of PWV; a PWV < 0.5 mm ಿ ೀ with some of the H2O ensures a transmission in the line peak maser spot emission 17 h 47 m 20.40s 20.20s 20.00s 19.80s 19.60s of > 35 %, with PWV of 0.3 mm required and spectra. RA (J2000) for transmission > 50 %. There are a number of other molecular lines of interest in Band 5, including HCN(2–1) at standard ALMA observing software with a pre-release version of the Cycle 5 177.3 GHz, HNC(2–1) at 181.3 GHz, Band 5 observations, and to determine ALMA control system.

CS(4–3) at 196.0 GHz, CH3OH(4–3) at the best calibration parameters to be 193.5 GHz and several SiO (J = 4–3) lines used in Band 5 Cycle 5 observations. As between 171.3 and 173.7 GHz, but none Band 5 had never been used with the SV observations of these is seriously affected by the H2O ALMA Observing Tool (OT) before, it was transmission unless the PWV is large important to check that Scheduling Block Sgr B2 (≳ 2 mm). See Table 1 and Figure 2 of (SB) generation worked as expected Sagittarius (Sgr) B2 is a massive and Immer et al. (2016) for an extended list of and that the SBs could be submitted to dense high-mass star-forming complex molecular lines in the band. the archive and successfully executed. situated at a projected distance of All SV observations were carried out with ~120 pc from the Galactic Centre. The An additional aspect of the SV observa- SBs created using an SV version of the cloud is well known for its rich chemistry tions was to test the compatibility of the OT, and observations were performed in and has been extensively studied with

8 The Messenger 167 – March 2017 submillimetre telescopes, including APEX 17.00 km s–1 17.86 km s–1 18.71 km s–1 and ALMA, with the goal of detecting complex organic molecules and understanding the chemical processes in the dense interstellar medium (for example, Belloche et al., 2013). Sgr B2 had already been observed in Band 5 with APEX SEPIA (Immer et al., 2016) so could provide an ideal comparison with the ALMA data. 19.56 km s–1 20.41 km s–1 21.26 km s–1

The almost complete range of Band 5 was observed with 13 receiver tunings and a hybrid array, consisting of 8–12 12-metre antennas with baselines of up to 1.6 km, with four 7-metre antennas included for some observations. Given the complexity of the source morphology, 12.9 ) the limited number of antennas used and 1.0 –1 –1 –1

) 22.12 km s 22.97 km s 23.82 km s 10.2

the sparse coverage of the (u,v) plane beam with the limited set of available baselines, 7.8 y/ 0.5 (J

second 5.7 y

the imaging of this dataset is challenging, rc 4.0 nsit and the image fidelity is relatively low (a

0.0 2.6 te in compared to typical ALMA observations. fset 1.4 d

The importance of this SV observation c of −0.5 0.6 De was to provide a complete spectral scan 0.2 larise of the whole of Band 5 to test the ability 0.0 Po 0.5 0.0 −0.5 to calibrate across the full band in varying RA offset (arcsecond) atmospheric absorption conditions. Figure 3. Spatially resolved velocity slices of the stellar magnetic field strength and mor- Figure 2 (upper) shows the ALMA and polarisation vectors in VY CMa superimposed on the phology. This may be important for polarised intensity image for the SiO maser line SEPIA spectra overlaid. A wealth of around 172.5GHz (from a report released with the understanding the mass-loss process molecular lines is revealed at a velocity ALMA data by Iván Martí-Vidal, Wouter Vlemmings from these stars, and the structures resolution of ~1 km s–1, many of which and Tobia Carozzi2). observable in the circumstellar enve- remain to be identified. For part of the lopes. For lower mass stars, such as observing time the H2O transmission was It is expected to eventually explode as a those on the Asymptotic Giant Branch, low enough to map some water maser core collapse supernova. It has a com- ALMA polarisation observations may emission clumps associated with the plex, extended and outflowing dusty and additionally provide information on the massive star formation (Figure 2, lower). molecular envelope with H2O and SiO processes leading to planetary nebulae. The comparison between the APEX and maser emission detected. The SV obser- In the SV dataset, one of the results is ALMA spectra shows that the brightest vations concentrated on measuring the that both the continuum and the SiO and lines, associated with more extended polarisation in continuum and in the H2O H2O maser emission towards VY CMa emission, are not fully recovered in the and SiO maser lines (at 183.3 and around are confirmed to be polarised. Maps of interferometric spectrum, because of the 172.5 GHz, respectively). Fifteen ALMA the polarisarisation vectors in SiO maser aforementioned limitations in the (u,v) 12-metre antennas and baselines up to emission are shown in Figure 3. coverage. The compact structures, 0.48 km were employed and again there including all absorption lines against the were previous APEX observations with Arp220 bright and compact continuum emission, which to compare. Arp 220 is the closest (at ~ 78 Mpc) ultra- 12 are well matched. luminous infrared galaxy (~ 4 × 10 L⊙) This is the first ALMA SV line polarisation representing an ongoing merger. The VY CMa dataset obtained and it was used to core has a very high star formation rate VY Canis Majoris is a red supergiant star check the observation and data reduc- and is a rich source of molecular emis- of spectral type M5 in a phase of strong tion procedures for this important sion. It has been extensively observed at –4 –1 mass loss (< 10 M⊙ yr ). The star is observing mode, expected to be used mm and radio wavelengths and displays very extended and of high luminosity for a variety of science cases and astro- H2O maser emission (at 22, 183 and 5 (~ 3 × 10 L⊙, for a distance of 1.2 kpc) nomical targets. For supergiant stars like 325 GHz). The 183 GHz water emission and the 25–32 M⊙ progenitor star is now VY CMa, it is anticipated that ALMA line was previously observed using the evolving blueward in the Hertzsprung- polarisation observations will make trans- Institut de Radioastronomie Millimétrique Russell diagram (Wittkowski et al., 2012). formational advances in understanding (IRAM) 30-metre telescope and APEX.

The Messenger 167 – March 2017 9 Telescopes and Instrumentation Humphreys L. et al., ALMA Band 5 Science Verification

30 m (2005) 200 30 m (2014) )

Jy APEX (2015) ALMA (2016) y (m 100 nsit te in

grat 0 te In

5000 5500 6000 Velocity (km s–1) Figure 4. Composite sub-mm/optical image of Arp 220 showing the Band 5 emission including HCN, Figure 5. The H2O 183.3 GHz line as observed with CS, SiO and H2O from the SV observation of the the IRAM 30-metre telescope in 2005 (Cernicharo et nuclear star forming region (in red) on top of an image al., 2005) and 2014, with SEPIA on APEX in 2015 from the NASA/ESA Hubble Space Telescope (blue/ (Galametz et al., 2016) and with ALMA in 2016 (König green). West is up and north left in this composite. et al., 2017), displaying the relative constancy of the The ALMA image was provided by Sebastien Muller line profile. From König et al. (2017). and Sabine König. See Release eso1645 for details.

Arp 220 has a double nucleus with the tion problems and finalise the calibration Itziar de Gregorio, Antonio Hales, Violette Impellizzeri, peaks of molecular emission separated and data release products. On 7 Decem- Andres Felipe Perez Sanchez, Neil Phillips, Adele Plunkett, Giorgio Siringo, Satoko Takahashi, the JAO by 1.1 arcseconds and the Band 5 obser- ber 2016, the Band 5 raw data, calibrated Extension and Optimisation of Capabilities (EOC) vations (beam size 0.7 arcseconds) data and reference images, as well as the Team and the JAO Department of Science Opera- tions (DSO) team members who performed the resolved the H2O emission into the east calibration scripts and detailed documen- and west nuclei (see Figure 4). The tation explaining the imaging and calibra- observations. The fantastic Band 5 receivers we have on ALMA would have not been possible without western component is brighter while the tion procedures, were publicly released the preproduction effort funded by the EU FP6 at 1 eastern one has a steep velocity gradient. on the ALMA SV page . At the Band 5 GARD and RAL, and without the cartridge optimisation and production effort at GARD, NOVA, and König et al. (2017) compared the H2O Workshop in February 2017 (see the fol- 183.3 GHz line profile with previous lowing article by de Breuck et al., p. 11), NRAO, and the Integration and Verification team on site in Chile supported by ESO, with contributions observations using the IRAM 30-metre analysis and results from these SV obser- from the National Astronomical Observatory of telescope (Cernicharo et al., 2006) and vations were presented and discussed. Japan (NAOJ). We thank Jeremy Walsh for his work the SEPIA Band 5 receiver on APEX on this article. (Galametz et al., 2016). The line profiles These SV observations allowed us to vali- are remarkably similar over a period of date and release the science operations References >10 years (see Figure 5). This is perhaps procedures to obtain successful ALMA unexpected for maser lines, which charac- Band 5 observations and resulted in the Belitsky, V. et al. 2017, A&A, in preparation teristically change in strength on time- inclusion of Band 5 as a standard mode Belloche, A. et al. 2013, A&A, 559, 147 Billade, B. et al. 2012, IEEE Trans. Terahertz scales of months to years. It is therefore in the Cycle 5 call for proposals. The Science Technology, 2, 208 suggested that the H2O profile represents datasets are now being used by astrono- Cernicharo, J. et al. 2006, ApJ, 646, L49 the emission of many unresolved maser mers in the community to perform scien- Galametz, M. et al. 2016, MNRAS, 462, L36 spots within the star-forming complex, so tificanalysis and to prepare for their own Immer, K. et al. 2016, The Messenger, 165, 13 König, S. et al. 2017, A&A, submitted, that, while individual masers vary, the observing proposals in the forthcoming arXiv:1612.07668 aggregate profile does not (König et al., ALMA Cycle. Wittkowski, M. et al. 2012, A&A, 540, 12 2017).

Links Acknowledgements Data Release 1 ALMA SV Band 5 data release: targets: Obtaining, validating and releasing the ALMA Band 5 https://almascience.eso.org/alma-data/science- SV data was a team effort involving a large number verification After the initial data collection and of people at ESO, the EU ARC Network and the Joint 2 Band 5 Polarisation Calibration Information: ALMA Observatory (JAO). We thank for their key assessment, an intensive workshop was https://almascience.eso.org/almadata/sciver/VYC- contributions Tobia Carozzi, Simon Casey, Sabine held at Chalmers University, Sweden MaBand5/VYCMa_Band5_PolCalibrationInforma- König, Ana Lopez-Sepulcre, Matthias Maercker, tion.pdf in October 2016 where participants from Iván Martí-Vidal, Lydia Moser, Sebastien Muller, Anita across the European ALMA Regional Richards, Daniel Tafoya, Wouter Vlemmings, Allison Centre (ARC) worked to solve the calibra- Man, John Carpenter, Paulo Cortes, Diego Garcia,

10 The Messenger 167 – March 2017 Telescopes and Instrumentation DOI: doi.org/10.18727/0722-6691/5002

Report on the ESO Workshop Getting Ready for ALMA Band 5 — Synergy with APEX/SEPIA

held at ESO Headquarters, Garching, Germany, 1–3 February 2017

Carlos De Breuck1 of being installed in ALMA and the pre ALMA, a full set of optimised receivers Leonardo Testi1 vious article (Humphreys et al., p. 7) was built by GARD and the Nederlandse Katharina Immer1 describes the Science Verification (SV). Onderzoekschool Voor Astronomie The timing was therefore right for a work- (NOVA) in Groningen, with the local oscil- shop on the Band 5 science already lators (LO) and warm electronics built 1 ESO achieved with SEPIA. by the National Radio Astronomy Obser- vatory (NRAO) in the USA. The goal of the meeting was to discuss The workshop provided an overview and highlight the role of APEX as an Giorgio Siringo from the Joint ALMA of the wide range of results from the ALMA complement and to encourage Observatory (JAO) gave a detailed pro- first two years of science operations European ALMA users to focus on the gress report of the installation and veri with the ALMA Band 5 (163–211 GHz) science that will be enabled by the new fication of the Band 5 receivers at ALMA. receiver in the Swedish ESO PI Instru- Band 5 receivers ahead of the ALMA Production and delivery of the receiver ment for APEX (SEPIA) ahead of the Cycle 5 call for proposals. The workshop cartridges is expected to be completed ALMA Cycle 5 call for proposals, when was attended by more than 50 astrono- (including all spares) by the end of 2017, the Band 5 receivers will be offered for mers and submillimetre instrument build- while completing the installation and veri- the first time. The frequency range of ers (see Figure 1) and also featured some fication for use within the ALMA antennas the Band 5 receiver has never been fully SEPIA science with the Band 9 receiver. depends on the scheduling of Front End covered by existing receivers; the talks maintenance at the Observatory. The presented at the workshop illustrate the current estimate is that Cycle 5 science importance of several lines in this fre- Development of the Band 5 receivers operations for Band 5 receivers will com- quency range that provide crucial diag- mence in March 2018 (see Humphreys et nostics of the interstellar medium. As explained by Victor Belitsky, who al., p. 7). gave the opening invited talk, the idea of building a receiver to cover the frequency SEPIA, the Swedish ESO PI Instrument gap between ALMA Bands 4 and 6, and Evolved star science with Band 5

for the Atacama Pathfinder EXplorer across the 183.3 GHz atmospheric H2O (APEX) was developed around a pre- absorption line, started in 2005. Thanks One of the areas where the Band 5 production Band 5 receiver (157–212 GHz) to a specific grant as part of the Euro- receiver has already made a significant built for the Atacama Large Millimeter/ pean Union’s Sixth Framework Program impact in its two years of science oper submillimeter Array (ALMA). It was (FP6), a first set of six “pre-production” ations at APEX is the field of evolved installed on APEX in early 2015 (Immer receivers was built by the Group for stars (overview talk by Elvire De Beck). et al., 2016), and is already being used Advanced Receiver Development (GARD) The outer layers of these stars are labo by European astronomers to reveal the at the Chalmers University of Technology ratories where a wide range of molecules new science that can be done in this in Gothenburg in collaboration with the are formed and fed into the interstellar relatively unexplored frequency band. Rutherford Appleton Laboratory (Billade medium (ISM) through stellar winds. The Band 5 receivers are in the process et al., 2012). After successful testing at Although no CO lines are present in Luis Calçada/ESO

Figure 1. The participants at the APEX/ ALMA Band 5 workshop outside the ESO Head- quarters building.

The Messenger 167 – March 2017 11 Telescopes and Instrumentation De Breuck C. et al., Report on the ESO Workshop “Getting Ready for ALMA Band 5”

Band 5, there are many other important 70 + Source 48 molecules such as HCN, HNC, HCO 1.0 (talk by Karl Menten), H2S (Taïssa Danilovich), and many others, including 0.8 key isotopomers to study fractionation, 60 0.6 which are found in spectral line surveys )

(K 0.4

(Elvire De Beck). By combining the con- MB T straints from these lines with spectral 0.2 surveys at other frequencies, one is now ) (K obtaining a full inventory of the circum- )] 50 0.0 11 stellar gas. This in turn allows the chemi- 2– –0.2 cal state to be constrained in the various (1 –80–60 –40–20 02040 H 2 Velocity (km/s) C

classes of evolved stars (for example, split 3 by chemical types or density regimes), H 40 [C and their different evolutionary paths. T

One important advantage of Band 5 is that the bright H O and SiO maser tran 2 30 sitions at 183.3 and ~173 GHz can be observed simultaneously (Liz Humphreys). This allows the physical conditions, dynamics and even the magnetic field strengths and morphologies throughout 20 1 10 100 the outflow to be traced. One of the L /M interesting new applications of the dual ๬ ๬ polarisation Band 5 receiver in SEPIA water vapour (PWV) < 0.5 mm, this Figure 2. CH3C2H(12–11) gas temperature as a was to look for polarised emission in SiO line does become observable from function of the luminosity to mass ratio (L/M) for high-mass protocluster candidates from the Hi-GAL and H O masers. As SEPIA is located in Chajnantor, and is a powerful probe of 2 survey. The inset shows one of the SEPIA CH3C2H the Nasmyth A cabin without a de-rotator, the ISM, as water controls the chemistry spectra (adapted from Molinari et al., 2016). recovering the polarisation angle is very of many other species (Floris van der complicated. However, one can still look Tak). The detection of H2O in proto 18 at the difference between the two polari- planetary disks will allow us to determine the optically thin H2 O line at 203 GHz, sations, and can thus identify which of and study the snowline, a key missing still within the Band 5 receiver frequency the maser lines are significantly polarised. piece of the puzzle to understand the range, one can determine the relative Humphreys et al. (submitted to A&A) have distribution of life-supporting volatiles in roles of maser versus thermal excitation indeed found that only some components planetary atmospheres. of water. of the SiO masers are polarised, while the

H2O emission is not. Nevertheless, such observations may When looking for water in external galax- be challenging even with the sensitivity ies, even a small redshift helps to improve The ability to perform accurate line and spatial resolution of ALMA (Michiel the atmospheric transmission. However, and polarisation observations is a key Hoogerheijde and Ruud Visser), requiring special care will have to be taken to prop- strength of the ALMA Band 5 receiver, significant time investment for this key sci- erly calibrate broad emission lines across as shown by the SV data for VY CMa ence goal of ALMA Band 5. As explained the varying atmospheric absorption in the (Humphreys et al., p. 7). In this source, by John Carpenter, Band 5 observations shoulders of the atmospheric water line. ALMA data showed that both SiO and of discs will also offer many other lines As discussed by Immer et al. (2016), the

H2O (as well as the continuum) show that will provide powerful diagnostics of application of APEX offline calibration is polarised emission. The combination of turbulence, the snowlines of various vola- required across the water absorption line APEX surveys with ALMA high-resolution tiles, nitrogen fractionation, deuteration to avoid large amplitude discrepancies follow-up in this area is thus expected and ionisation. As a byproduct of any line across the SEPIA passband. Upgrades to produce transformational results in the observations of discs with ALMA, it will of the APEX OnlineCalibrator are planned coming years. be possible to observe the dust emission to provide this higher-resolution calibra- at high spatial resolution to probe grain tion by default. properties using continuum and polarisa- The 183.3 GHz water line tion measurements. SEPIA observations of extragalactic water have led to the confirmation of the previ-

The most challenging Band 5 obser- Friedrich Wyrowski reported strong H2O ously reported H2O line in the ultra-lumi- vation is across the 31,3–22,0 atmospheric detections in hot molecular cores using nous infrared galaxy Arp 220 at z = 0.018 absorption line of H2O centred at SEPIA. When combined with other water (Galametz et al., 2016), and a weaker 183.3 GHz. However, with precipitable lines at higher frequencies, in particular tentative detection in IRASF17207-0014

12 The Messenger 167 – March 2017 at z = 0.043 presented by Zhi-Yu Zhang 6 H CO 3(0,3)–2(0,2) (Yang et al., in prep.). The Arp 220 system 2 IRAM was also observed as part of the ALMA 4 Band 5 SV (Humphreys et al., p. 7). The comparison of the APEX, ALMA and pre- 2 vious observations of the water line shows a remarkable stability (in terms of 0 H 13CO 3(1,3)–2(1,2) intensity and line profile) of this masing 0.3 2 IRAM line in Arp 220 (König et al., 2017); see 0.2 Figure 5 of Humphreys et al., p. 7. 0.1

0 Other gas tracers in Band 5 0.1 HDCO 3(2,1)–2(2,0) SEPIA The first spectral line surveys in Band 5 0.05 have already shown a remarkable rich- ness of molecular lines, as illustrated, for 0 example, by the Sgr B2(N) spectrum observed with both ALMA and SEPIA 0.1 (Fig. 5 of Humphreys et al. p. 10), or the HDCO 3(2,2)–2(2,1) SEPIA

D-Dor survey shown in De Beck’s talk. ) 0.05 (K Apart from the aforementioned H O and 2 MB 18 T 0 H2 O lines, which probe the location of the snowline and the thermal structure –0.05 in disks, the SO2 line can be used to determine the shock chemistry and sys- 0.4 HDCO 3(1,3)–2(1,2) SEPIA tem geometry, while the CH3OCH3 and C2H5CN lines provide information on the 0.2 grain surface chemistry (van der Tak). The CH3C2H line has also been used as 0 a powerful temperature probe for dense gas (Molinari et al., 2016). By selecting 0.4 HDCO 3(0,3)–2(0,2) SEPIA dense clumps from the Hi-GAL survey of our Galaxy, Sergio Molinari and Manuel 0.2 Merello reported a remarkably strong correlation between the CH C H line 3 2 0 strength and the luminosity–mass ratio 0.15

(Figure 2). D2CO 3(0,3)–2(0,2) SEPIA 0.1

The presence of important H, C, N, O, 0.05 HMSC HMPO and S isotopomers for several key mole- 0 cules in this band will also allow to extend important work on element fractionation –0.05 in various phases of the interstellar –20020 Velocity (km s–1) medium. Examples discussed at the 18 Figure 3. SEPIA HDCO and D CO spectra for the workshop included (besides H2 O/H2O the other lines such as HCN, HNC and 2 high-mass star-forming region AFGL 5142, compared studies) the studies of H fractionation CO. A first mapping campaign has been 13 with H2CO and H2 CO measurements from the using some of the (3–2) lines of singly and started to better probe the origin of these Institut de Radioastronomie Millimétrique (IRAM) doubly deuterated formaldehyde (Sarolta variations (see Figure 4). 30-metre telescope (adapted from Zahorecz et al., Zahorecz) and potentially the study of the 2017). The blue profile is associated with the high- 14N/15N ratio using the (2–1) lines of HNC, mass starless cores (HMSC) and the red profile with the high-mass protostellar objects (HMPO). HCN and N2H+ isotopomers (Figure 3). The high redshift Universe

In star-forming regions, the brightest lines Kirsten Knudsen and Maria Strandet the redshift coverage of the CO(2–1) line in Band 5 are the 2–1 transitions of HCN, summarised the role of Band 5 for high- out to z = 0.46, and SEPIA has already HNC and HCO+. In a pilot survey of redshift science, highlighting respectively started to fill the existing redshift gap pointed observations within the LMC and the CO and fine structure lines that move (from Edo Ibar). To cover the CO spectral SMC, Maud Galametz found large spatial into the frequency range of Band 5 for line energy distribution, continuous fre- variations between the HCO+(2–1) and different redshift ranges. Band 5 extends quency coverage is essential (from Bitten

The Messenger 167 – March 2017 13 Telescopes and Instrumentation De Breuck C. et al., Report on the ESO Workshop “Getting Ready for ALMA Band 5”

0.4 0.2 0 SDP.11 [C II] 0.4 400 SEPIA B9 0.2 ) 0 Jy 0.4 0.2 y (m 200 0

0.4 densit 0.2 0 0 Flux ) 0.4

* (K 0.2 A T 0 0.4 –200 0.2 0 0.4 CO J = 4–3 0.2 PdBI 0 ) 10

0.4 Jy 0.2 0 y (m 0.4 5 0.2 densit 0 –5050–50 50 Flux –1 Velocity (km s ) 0

Figure 4. An HCO+(2–1) map of the Large Magellanic Cloud region N159W obtained with APEX/SEPIA Band 5 (Galametz et al., in prep.). –500 0500 Velocity (km s–1)

Gullberg). For fine-structure lines, the lines, such as the z ~ 1.9 [C II] lines Figure 5. The [C II] 158 µm line detected with the most important lines shifting into Band 5 observed during SV by Zhi-Yu Zhang Band 9 receiver of SEPIA in the z = 1.8 dusty star- forming galaxy SDP.11 (Zhang et al., in prep.). The at 1.33 < z < 2.11 and 2.84 < z < 4.13 (Figure 5), and the tentative [O III] 88 µm velocity profile in this short SEPIA observation is fully are the [C I] 609 µm and 370 µm lines, detections by Carlos De Breuck. The consistent with the IRAM Plateau de Bure CO(4–3) respectively. Paola Andreani and Matt Sgr B2(N) spectral scan highlighted the data of Oteo et al. (2017). Bothwell highlighted the importance of difficulty of using the current double the [C I] line as an alternative tracer for sideband (DSB) receiver for line-rich the H2 mass, and reported several SEPIA sources, due to overlapping signal com- how to optimally use the query forms. detections. By filling the frequency gap ing from the two sidebands (Katharina Future developments (for example, better in the ALMA coverage, the SEPIA Band 5 Immer). With future upgrades to a side- visualisation tools) were also mentioned receiver has also manifested itself as an band-separating receiver and a doubling on how to better mine the ALMA and ideal follow-up instrument for ALMA, of the spectral bandwidth, we can hope APEX data archives. confirming ambiguous redshifts obtained for an APEX pathfinding role for ALMA in with ALMA Band 3 spectral scans this band too. (Strandet et al., 2016). Acknowledgements

The practical sessions would not have been possible Practical sessions without the help of the tutors Francisco Montenegro, Synergy with Band 9 Kalle Torstensson, Paulina Venegas, Claudio Agurto, As Band 5 has some special features Suzanna Randall and Felix Stoehr. Thanks go to While the main topic of the meeting was due to the presence of the deep atmos- Baobab Lu for his help collecting the presentations from the speakers, to Rein Warmels for help setting the Band 5 receiver, the other receiver pheric absorption feature, the ALMA up the web pages, and especially to Stella Klingner currently installed inside SEPIA, a Band 9 Regional Centre and APEX staff explained for the smooth organisation of the workshop. (600 to 722 GHz) ALMA receiver, has a to the participants how to optimally pre- very similar synergy with ALMA. pare for their Service Mode observations. References Users should in particular pay attention A number of talks presented first results, to the placement of the image band, as Belitsky, V. et al. 2017, A&A, in preparation such as the intriguing ArH+ line results this may have little transparency if placed Billade, B. et al. 2012, IEEE Trans. Terahertz Science in the Crab Nebula (Ilse De Looze) and near the 183 GHz band. The new fea- Technology, 2, 208 Galametz, M. et al. 2016, MNRAS, 462, L36 the 658 GHz vibrationally excited water tures in both the ALMA Observing Tool Immer, K. et al. 2016, The Messenger, 165, 13 lines presented by Alain Baudry. Even and the APEX Phase 2 web submission König, S. et al. 2016, A&A, submitted, for extragalactic science, the Band 9 tool were also presented. As the ALMA arXiv:1612.07668 receiver now has sufficient bandwidth to and APEX archives are also growing Molinari, S. et al. 2016, ApJ, 826, 8 Oteo, I. et al. 2017, ApJ, submitted, arXiv:1701.05901 allow the detection of broad emission steadily, demonstrations were given of Strandet, M. et al. 2016, ApJ, 822, 80

14 The Messenger 167 – March 2017 for details. potw1706a Week the of Picture ESO See Type II). SN, collapse 2007c SN core (a and (a Type Ia) 1968I SN supernovae, two had has NGC 4981 27 Mpc, about of adistance At composite. colour a FORS2 in shown is NGC 4981 The grand design (SBbc) barred spiral galaxy B -, -, V -, -, R -band

Astronomical Science Astronomical Science DOI: doi.org/10.18727/0722-6691/5003

Minor Planet Science with the VISTA Hemisphere Survey

Marcel Popescu1,2 resources for space exploration; and in The survey conducted with the Visible Javier Licandro3,4 order to mitigate the risk of impacts by and Infrared Survey Telescope for Astron- David Morate3,4 near-Earth objects. omy (VISTA), the VISTA Hemisphere Sur- Julia de León3,4 vey (VHS1), provides such a survey for Dan Alin Nedelcu1,2 The physical properties of minor planets minor planets. VHS is the largest survey are known for just a small fraction of being conducted by the VISTA telescope. these objects: spectroscopic studies and VHS images the entire southern hemi- 1 Astronomical Institute of the Romanian light curves exist only for several thou- sphere using four filters in the near- Academy, Bucharest, Romania sand. The results show an unexpected infrared region, namely Y, J, H and Ks 2 IMCCE, Observatoire de Paris, PSL diversity in the composition, density and (McMahon et al., 2013; Cross et al., 2012). Research University, CNRS, Sorbonne shape of these bodies. The Sloan Digital The band centres of these filters are Universités, UPMC Univ Paris 06, Sky Survey (SDSS) and Wide-field Infra- located at 1.02, 1.25, 1.65 and 2.15 μm Université de Lille, France red Survey Explorer (WISE) provide infor- respectively. Figure 1 shows the trans- 3 Instituto de Astrofísica de Canarias mation for about 100 000 minor planets. mission curves of the VISTA filters com- (IAC), La Laguna, Tenerife, Spain The resulting visible colours and albedos pared to the spectra of two of the most 4 Departamento de Astrofísica, Univer show a greater mixing of the bodies as typical asteroid classes, the primitive sidad de La Laguna, Tenerife, Spain a function of their orbital parameters, C-type and the rocky S-type. Notice that which can be explained by the turbulent these four filters allow sampling of some history of the Solar System (DeMeo et al., of the main spectral features we expect We have carried out a serendipitous 2015 and references therein). However, for asteroids: the spectral slope and the search for Solar System objects imaged some of the most important spectral fea- two wide absorption bands at 1 and by the VISTA Hemisphere Survey (VHS) tures used to reveal the compositions of 2 μm, produced by minerals like olivine and have identified 230 375 valid detec- minor planets are in the near-infrared and pyroxene. tions for 39 947 objects. This informa- region. A large survey with observations tion is available in three catalogues, sampling this spectral region allows us to entitled MOVIS. The distributions of the refine and complement the global picture Detection of minor planets in VHS data in colour-colour plots show clusters of these bodies provided by SDSS and identified with the different taxonomic WISE data. With the aim of characterising the minor asteroid types. Diagrams that use (Y–J) planet population in the VHS, we per- colour separate the spectral classes formed a serendipitous search within the more effectively than any other method observational products of the survey. In Figure 1. The normalised throughput profiles of the based on colours. In particular, the end- VISTA filter compared with two asteroid spectral order to detect the minor planets, we class members A-, D-, R-, and V-types types. used the fact that Solar System objects occupy well-defined regions and can be easily identified. About 10 000 aster- 1 oids were classified taxonomically using S-type a probabilistic approach. The distribution of basaltic asteroids across the C-type Main Belt was characterised using the 0.8 MOVIS colours: 477 V-type candidates Filters were found, of which 244 are outside the Vesta dynamical family.

s 0.6

Context unit y The total number of minor planets (small ar Solar System bodies orbiting the Sun) Arbi tr 0.4 known today exceeds 700 000. The vast majority of them are concentrated between the orbits of Mars and Jupiter, in the asteroid Main Belt. These objects are the remnants of planetesimals from which 0.2 YJ HKs the planets formed, and understanding their properties in detail allows the formation and evolution of the Solar System to be constrained. Other arguments for studying minor planets are related to 0.5 1.02 1.25 1.65 2.15 more practical reasons: their use as Wavelength (μm)

16 The Messenger 167 – March 2017 Figure 2. (Left) False- colour image obtained J by combining the stack J H of frames observed with H Ks J, H and Ks filters on Ks 5 November 2010. Owing to the differential motion of 0.24 arcseconds per minute, the asteroid (5143) Heracles appears as a different source in each filter.

Figure 3. (Right) False- colour image obtained by combining the stack Heracles of frames observed with Comet 279P J, H and Ks filters for the comet 279P. appear as moving sources compared MOVIS-D contains the parameters corre- information to be inferred (Popescu et with the background stars. This is exem- sponding to all detections; MOVIS-M al., 2016a). plified in Figure 2, using a false-colour contains the magnitudes obtained with image obtained by combining the stack different filters for each object and The VHS-DR3 release covers ~ 40 % of of frames observed with J-, Ks- and selected by taking into account the timing the planned survey sky area; thus by the H-band filters on 5 November 2011 at constraints; and MOVIS-C lists the colours end of the survey the total number of 02:32, 02:42 and 02:52 UT, respectively. which are useful to infer the mineralogy. Solar System objects observed will be at In this case, the near-Earth asteroid least double these numbers. (5143) Heracles moved about 2.5 arcsec- The MOVIS catalogues are available onds between the three consecutive online via the Centre de Données observations and hence appears as three astronomiques de Strasbourg (CDS2) Near-infrared colours of minor planets separate images compared with the portal. The information provided includes background stars. observational details, and photometric In order to derive compositional informa- and astrometric measurements. The tion for minor planets, it is necessary to Identifying the Solar System objects astrometric positions, corresponding to correlate the spectral behaviour with the observed in a given field requires cross- 230 375 valid detections, were submitted colours. This can be accomplished using matching of the detected coordinates to the International Astronomical Union the taxonomic classes of asteroid spec- with those computed at the moment of Minor Planet Center3, and all of them were tral data (since the large majority of the observation. A dedicated pipeline — validated. The observatory site received objects are asteroids). The main goal of called MOVIS (Moving Objects VISTA the code W91-VHS-VISTA. taxonomies is to identify groups of aster- Survey) was designed for this task. The oids that have similar surface composi- first step consists of predicting the posi- The first published catalogues (Popescu tions. The fact that spectra similar to the tion of Solar System objects potentially et al., 2016a) used the VHS-DR3 data templates proposed by the taxonomic imaged in each field and retrieving the release, which contains the observations systems were systematically recovered corresponding detections from the sur- performed between 4 November 2009 by independent authors using diverse vey products. Secondly, MOVIS removes and 20 October 2013. A total of 39 947 data sets and different methodologies the mis-identifications based on an algo- objects were detected, including 52 provides confidence in these systems. rithm that takes into account the differ- Near Earth Asteroids (NEAs), 325 Mars ence between the observed and the Crossers, 515 Hungaria asteroids, The first approach consisted of analysing computed (O–C) positions and also by 38 428 Main Belt asteroids, 146 Cybele the observed MOVIS-C colours for the comparing with the PPXML star cata- asteroids, 147 Hilda asteroids, 270 objects already classified taxonomically. logue (of positions, proper motions, Two Trojans, 13 comets (see example in Fig- There are about 185 objects with spectra Micron All Sky Survey [2MASS] near- ure 3), 12 Kuiper Belt objects and obtained by the Small Main-belt Asteroid infrared and optical photometry). Finally, Neptune with its four satellites. About Spectroscopic Survey (SMASS) and the the information is provided in three cata- 10 000 objects have accurate spectro- S3OS2 visible spectroscopic survey of logues for the purpose of organising the photometric data (i.e., magnitude errors 820 asteroids. Within an error of ~ 5 %, the data for different types of analysis: less than 0.1) allowing compositional main compositional groups are completely

The Messenger 167 – March 2017 17 Astronomical Science Popescu M. et al., Minor Planet Science with the VISTA Hemisphere Survey

Figure 4. Left panel: the ACDSVX ACDSVX 0.9 colours of asteroids with visible spectra, having an assigned taxonomic type. Right panel: the 0.7 colours computed for the template spectra of the taxonomic classes J 0.5 from DeMeo et al. Y– (2009) compared with the MOVIS-C data with colour errors less than 0.3 0.033 mag. From Popescu et al. (2016a). N = 185 N = 1335 0.1

–0.1 0.30.7 1.1 –0.1 0.30.7 1.1 J–Ks J–Ks separated (Figure 4) using the (Y–J) veras the end taxonomic type members A-, in the early age of the Solar System. This sus (J–Ks) colour-colour plot (Popescu D-, R-, and V-types (Popescu et al., hypothesis challenges the models of the et al., 2016a). This is the case for S-, C-, 2016a). This survey thus provides an radial extent and the variability of the A-, D-, V- and C-type asteroids. S-type important tool for investigating the faint early Solar System temperature distribu- are objects with spectra similar to ordi- asteroids which are hard to observe tion, which generally do not predict melt- nary chondrite meteorites; C-type spec- spectroscopically. ing temperatures in this region. V-type tra are similar to carbonaceous chon- asteroids with orbits in the middle and drites; A-type are olivine-rich asteroids; Based on the available data we were able outer part of the Main Belt are unlikely to D-type are objects with low albedo and a to classify about 10 000 objects using be scattered Vesta family objects. featureless red spectrum; V-type are a probabilistic approach which takes into asteroids with a basaltic composition, the account the errors in the object pho Near-infrared colours allow the easy iden- most representative one being the aster- tometry and the position of the class in tification of the V-type candidates: asteroid (4) Vesta. The X-types present fea- colour space (Popescu et al., 2017). oids with (Y–J) > 0.5 and (J–Ks) > 0.3 mag tureless spectra with a moderate slope A further step is to integrate into this are likely to be members of this class. and are representative of objects of dif- schema the photometric data obtained Using the more accurate MOVIS-C data ferent compositions: primitive, like carbo- by SDSS and WISE. (with uncertainties < 0.1 mag), and the naceous chondrites; or metallic, like colour criteria described above, we have enstatite chondrites. Knowledge of the identified 477 objects, of which 244 of the albedo is necessary to derive composi- A particular case: the basaltic asteroids V-type candidates are outside the Vesta tional information of an X-type asteroid. dynamical family (Figure 5). This sample Basaltic asteroids are considered to be almost doubles the number of known The second approach is to compare the fragments of large bodies whose interiors V-types that are not members of the distribution of MOVIS-C data in colour- reached the melting temperature of sili- Vesta family (Licandro et al., 2016). In colour space with the position of colours cate rocks and subsequently differenti- particular we identified 19 V-type aster- computed for the template spectra of the ated (a core of heavy minerals is formed oids beyond the 3:1 mean motion reso- different taxonomic classes spanning the with a mantle of lighter minerals, such nance, 13 of them in the middle part of visible to the near-infrared region (DeMeo as olivine and pyroxene). These asteroids the Main Belt and six in the outer part. et al., 2009). are classified as V-types and are identified by their spectrum in the 0.5–2.5 μm In Popescu et al. (2016a) we show that region which shows two deep and sharp Acknowledgements the (Y–J) colour is a key parameter for a absorption bands at 0.9 and 2 μm. Most The observations were obtained as part of the VISTA taxonomic classification: those with the of the objects with these characteristics Hemisphere Survey, ESO Programme 179.A-2010 1 μm band have a large value of (Y–J) orbit in the inner part of the Main Belt (PI: R. McMahon). J. de León acknowledges support colour. The colour-colour plots which use and are members of the Vesta collisional from the IAC. D. Morate acknowledges the Spanish MINECO for financial support in the form of a the Y filter allow separation of the taxo- family, or are likely scattered members of Severo-Ochoa Ph.D. fellowship. J. Licandro, D. nomic classes much better than has pre- this family. These objects are chunks of Morate, J. de León, and M. Popescu acknowledge viously been possible using other col- the crust of the asteroid (4) Vesta, ejected support from the project ESP2013-47816-C4-2-P ours. Even for large photometric errors from it due to a collision. The presence of (MINECO, Spanish Ministry of Economy and Com- petitiveness). The work of D. A. Nedelcu, and part (up to 0.15 mag), the diagrams (Y–J) vs basaltic asteroids, unlikely to be scat- of the work of M. Popescu, were supported by a (Y–Ks) and (Y–J) vs (J–Ks) clearly sepa- tered members of the Vesta family, clearly grant from the Romanian National Authority for rate the asteroids belonging to the main shows that there were other big differen- Scientific Research — UEFISCDI, project number spectroscopic S- and C-complex, as well tiated basaltic asteroids in the Main Belt PN-II-RU-TE-2014-4-2199.

18 The Messenger 167 – March 2017 Figure 5. Distribution in References Vesta proper orbital elements 0.4 non-Vesta of the V-type candidates Cross, N. J. G. et al. 2012, A&A, 548, A119 from the VHS survey. DeMeo, F. E. et al. 2009, Icarus, 202, 160 3:15:2 2:1 The figure shows the DeMeo, F. E. et al. 2015, Asteroids IV, University of proper semi-major axis Arizona Press, 13 0.3 (ap) vs the sine of the Licandro, J. et al. 2016, A&A, submitted proper inclination (ip). McMahon, R. G. et al. 2013, The Messenger, 154, 35 Red circles are Vesta Popescu, M. et al. 2016a, A&A, 591, A115 P

i family members, while Popescu, M. et al. 2017, in preparation

n blue circles indicate si 0.2 objects out of the Vesta family. The vertical Links dashed lines corre- spond to the most rele- 1 VHS: http://www.vista-vhs.org/ 0.1 vant mean motion reso- 2 CDS catalogues: nances (Licandro et al., http://cdsarc.u-strasbg.fr/viz-bin/Cat 2016). 3 IAU Minor Planet Center: http://www.minorplanetcenter.net/iau/mpc.html 4 0 http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/ 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.23.4 A%2BA/591/A115

aP R. Wesson/ESOR.

Composite image of sunset and star trails over the La Silla Observatory photographed from the 3.6-metre telescope with a series of long exposures. See Picture of the Week potw1647 for information.

The Messenger 167 – March 2017 19 Astronomical Science DOI: doi.org/10.18727/0722-6691/5004

The Nearby Evolved Star L2 Puppis as a Portrait of the Future Solar System

1,2 Pierre Kervella Five billion years from now, the Sun will tudes in the visible, L2 Pup has experi- Miguel Montargès3 grow into a red giant star, more than a enced a remarkable, slow photometric Anita M. S. Richards4 hundred times larger than its current size. dimming over the last decades by more Ward Homan5 It will also experience intense mass loss than 2 magnitudes in the visible. Bedding Leen Decin5 in the form of a stellar wind. The end et al. (2002) interpreted this long-term Eric Lagadec6 product of its evolution, seven billion dimming as the consequence of the Stephen T. Ridgway7 years from now, will be a white dwarf star obscuration of the star by circumstellar Guy Perrin2 — about the size of the Earth and ex dust. Iain McDonald4 tremely dense (density ~ 5 × 106 g cm–3). 8 Keiichi Ohnaka We observed L2 Pup on the night of This metamorphosis will have a dramatic 21 March 2013 with NAOS CONICA impact on the planets of the Solar Sys- (NACO) as part of a survey aimed at 1 Unidad Mixta Internacional Franco- tem, including the Earth. While Mercury imaging the circumstellar environments Chilena de Astronomía (CNRS UMI and Venus will be engulfed by the giant of selected nearby evolved stars (Kervella 3386), Departamento de Astronomía, star and destroyed, the fate of the Earth et al., 2014a). We used 12 narrow-band Universidad de Chile, Santiago, Chile is still uncertain. The brightening of the filters spread in wavelength between 1.04 2 LESIA (UMR 8109), Observatoire de Sun will make the Earth hostile to life in and 4.05 µm. We processed the image Paris, PSL Research University, CNRS, about one billion years. As an aside, cubes using a serendipitous imaging UPMC, Université Paris-Diderot, France assuming that life appeared on Earth approach (also known as “Lucky imag- 3 Institut de Radioastronomie Millimétri 3.7 billion years ago (Ohtomo et al., 2014), ing”). Using 8400 very short exposures que, Saint-Martin d’Hères, France this implies that life on Earth has already (8 milliseconds each) in each filter, we 4 Jodrell Bank Centre for Astrophysics, exhausted ~ 80 % of its development were able to freeze the residual atmos- Dept. of Physics and Astronomy, Uni- time. However, we do not know whether pheric perturbations. After selecting the versity of Manchester, United Kingdom our then-lifeless rock will be destroyed by best 50 % of the series of images, we 5 Institute of Astronomy, Katholieke the burgeoning Sun, or survive in orbit recentred and averaged them to obtain Universiteit Leuven, Belgium around the white dwarf. the 12 final, diffraction-limited images. 6 Laboratoire Lagrange (UMR 7293), They were finally deconvolved using a Université de Nice-Sophia Antipolis, To address the question of the impact of point spread function (PSF) calibrator

CNRS, Observatoire de la Côte d’Azur, the final phases of stellar evolution on star. The morphology of L2 Pup in these Nice, France planetary systems, hydrodynamical mod- images (Figure 1) was very surprising. 7 National Optical Astronomy Observa els have been proposed (see, for exam- From a seemingly double source between tory, Tucson, USA ple, the recent review by Veras, 2016). 1.0 and 1.3 µm, the star became a single 8 Instituto de Astronomía, Universidad But observational constraints on the star- source with an east-west extension at Católica del Norte, Antofagasta, Chile planet interaction models are still rare. 2.1 µm, and exhibited a spectacular spiral Planets of asymptotic giant branch (AGB) loop at 4.0 µm! stars are embedded in complex circum- The impact of the dramatic terminal stellar envelopes and are vastly outshone We proposed (Kervella et al., 2014a) that phases of the lives of Sun-like stars on by their parent star. The observation of L2 Pup is surrounded by an equator-on their orbiting planets is currently uncer- this critical phase of planetary system dust disc. In this framework, the opacity tain. Observations with NAOS CONICA evolution thus presents considerable, and and thermal emission of the dust change and SPHERE/ZIMPOL in 2014–2015 as yet unsolved, technical challenges. As dramatically between 1 and 4 µm, provid- have revealed that the nearby red giant a result, there currently exists only indi- ing a natural explanation for the changing star L2 Puppis is surrounded by an rect evidence of the presence of planets aspect of the circumstellar envelope. At almost edge-on disc of dust and gas. orbiting AGB stars (Wiesemeyer et al., 1 µm, the dust efficiently scatters the light We have observed several remarkable 2009). In addition, the masses of AGB from the star, which therefore appears features in L2 Pup: plumes, spirals, and stars are notoriously difficult to estimate masked behind the dust band. The dust a secondary source (L2 Pup B) which from observations, preventing accurate becomes progressively more transparent is embedded in the disc at a projected determinations of their evolutionary as the wavelength increases. At 2.2 µm, separation of 2 au. ALMA observations states. the thermal emission from the hot inner have allowed us to measure a mass of rim of the disc is observable through the

0.659 ± 0.043 M⊙ for the central star. dust. A colour composite image of This indicates that L2 Pup is a close The discovery of the disc of L2 Puppis L2 Pup in the near infrared is presented analogue of the future Sun at an age with NACO in Figure 2. It shows the intrinsically red of 10 Gyr. We also estimate the mass of colour of the equatorial dust band due

L2 Pup B to be 12 ± 16 MJup, implying At a distance of only 64 pc (van Leeuwen, to the stronger scattering at shorter that it is likely a planet or a brown 2007), L2 Pup is the second nearest wavelengths. dwarf. L2 Pup therefore offers us a AGB star after R Doradus. In addition to remarkable preview of the distant future its regular pulsation with a period of Our hypothesis of an edge-on dust disc of our Solar System. 141 days and an amplitude of ~ 2 magni- was initially relatively fragile. But a 3D

20 The Messenger 167 – March 2017 1.04 μm 1.26 μm 2.12 μm 4.05 μm

N E 50 mas 5 au

Figure 1. NACO deconvolved images of L2 Puppis elongated, and the subtraction of the Sparks et al. (2008) and Kervella et al. at a range of wavelengths from 1 to 4 μm. From central star revealed the presence of a (2014b). Kervella et al. (2014a). second source, L2 Pup B, at a separation of 32 milliarcseconds (mas) from the star Apart from the scattered light on the radiative transfer model using the to the west (Figure 3). disc’s upper and lower surfaces, a very

RADMC-3D code (Dullemond, 2012) striking signature in the pL map (Figure 3, confirmed that this interpretation of the The polarimetric imaging capability of right panel) comes from the two plumes NACO images is consistent with the ZIMPOL has been particularly important emerging from the disc. Their high observations, reproducing convincingly in revealing the structure of the envelope degree of polarisation (~ 30 %) indicates both the spectral energy distribution and of L2 Pup (Figure 3, right). As the star that they contain dust and that the scat- the morphology of the disc (Kervella et is embedded in a dust-rich environment, tering angle is large at θ ~ 50°. These thin al., 2014a). the scattering of the starlight by the dust plumes, whose transverse diameter is grains induces a linear polarisation of smaller than 1 au, have a length of more the photons. For small dust grains, the than 10 au. The large scattering angle

Stunning features from SPHERE polari- degree of linear polarisation pL is a implies that they emerge from the disc metric imaging smooth function of the scattering angle, close to perpendicular, and propagate in

with a maximum pL value obtained for the northern cone cavity that is otherwise We took advantage of the Science Verifi- ~ 90° scattering. Knowing the degree of essentially devoid of dust. cation of the Spectro-Polarimetric High- polarisation therefore allowed us to esti- contrast Exoplanet REsearch instrument mate the scattering angle θ over the The map of the degree of polarisation (SPHERE) to observe L2 Pup in visible envelope. Knowing θ and the projected also shows well-defined local maxima at light imaging polarimetry with the Zurich position of the dust relative to the star in a radius of 6 au, symmetrically east and IMaging POLarimeter (ZIMPOL) camera the image, then allowed us to retrieve the west of the star. The degree of polarisa- (Kervella et al., 2015). The observation 3D distribution of the scattering material. tion reached at these positions is very was carried out on the night of 7 Decem- This polarimetric tomography technique high, up to pL = 60 % in the R-band, cor- ber 2014. The combination of the high was previously employed, for example, by responding to scattering of the light at brightness of L2 Pup and good seeing resulted in spectacular image quality. The Strehl ratio produced by the SPHERE adaptive optics reached more than 40 % at a wavelength of 646 nm for an atmospheric seeing of ~ 0.7 arcseconds. In one hour of telescope time, the observation of L2 Pup and a PSF calibrator star (β Col) confirmed unambiguously our hypothesis of an edge-on circumstellar dust disc (Figure 3, upper left). In addition to revealing the overall geometry of the dust disc 0.1ೀ — as relatively thin, moderately flared Figure 2. Colour composite image of L Pup and extending to at least 13 au — the 2 at infrared wavelengths collected images in the V- and R-bands assembled from NACO showed remarkable structures in the Jupiter observations. The orbits Earth Saturn Uranus of four Solar System envelope of L2 Pup (Figure 3, upper right). We detect several spiral arms in the neb- planets are represented in the lower part of the ula, as well as two intriguing thin plumes. figure to give the overall

The central source appeared significantly scale of the L2 Pup disc.

The Messenger 167 – March 2017 21 Astronomical Science Kervella P. et al., Evolved Star L2 Puppis as a Portrait of the Future Solar System

V-band p Plume 2 L Plume 2 Plume 1 Northern cone Loop Plume 1 Max. pL Spiral 1 Segment Max. pL Edge A B 3 au Band AB

Max. pL Max. N N Spiral 2 pL

Southern cone E E 5 au 100 mas 5 au 100 mas

Figure 3. Left: Colour composite intensity image of 0.1 0.20.3 0.40.5 L2 Pup assembled from SPHERE/ZIMPOL V- and R-band images. Middle: nomenclature of the observed structures in the circumstellar environment high brightness of L2 Pup and the high two-thirds the mass of our Sun (0.653 ± of L2 Pup. Right: degree of linear polarisation, pL, of sensitivity of the array. We detected 0.043 M⊙). It is remarkable that the error L2 Pup measured with ZIMPOL. The two plumes several molecular emission lines in the budget of this measurement is fully domi- sketched in the middle panel are also indicated. selected spectral windows, from 12CO, nated by the uncertainty in the parallax 13 29 CO, H2O, SO2, SiO, SiS and SO. of L2 Pup, as the error from the ALMA We focus our discussion here on the data fit is only ± 1.7 %. ~ 90°. We interpret these maxima as the 29SiO(ν = 0, J = 8–7) molecular line at a scattering of the starlight by the inner rim rest frequency of 342.981 GHz. The con- The coincidence of the radius where the of the dust disc, that is, the minimum tinuum subtracted integrated intensity rotation becomes sub-Keplerian and the radius at which the dust is present with a in this line is presented in Figure 4 (upper radius of the inner rim (maximum of pL, high density. The existence of an inner left panel). Figure 3) of the dust disc observed with rim is due to the very high brightness of ZIMPOL indicates that the rotation of the the central star (2000 times Solar lumi- Our analysis is based on the position- gas becomes sub-Keplerian precisely nosity), which would lead to the sublima- velocity diagram (PVD) formalism. The when it enters the dust disc. This very tion of any dust grains closer to the star PVD is computed by integrating the interesting effect is likely due to the vis- (Homan et al., 2017). ALMA spectro-imaging data cube over cous coupling of the gas and dust within a 0.02 arcsecond wide pseudo-slit the disc. The dust is sensitive to the aligned with the disc plane (east-west strong radiative pressure from the central An analogue of the future Sun, 5 billion direction). The resulting diagram (Figure star, and is thus subject to a reduced years from now 4, lower left) shows the velocity of the effective gravity resulting in a slower molecular gas as a function of the posi- orbital velocity than the gas. As the inter-

L2 Puppis was observed with the tion along the slit. Thanks to the excellent nal cavity within 5 au contains very little Atacama Large Millimeter/submillimeter signal-to-noise ratio of the ALMA data, dust, the gas rotates freely there. But Array (ALMA) in Cycle 3 in Band 7 we can measure very accurately the when it reaches the inner rim of the dust (340 GHz, wavelength ~ 0.8 mm) using orbital motion of the gas in the disc disc, it is slowed down by friction with the longest available configuration of the plane, and more precisely the maximum the dust, which explains its sub-Keplerian interferometer with baseline lengths of up velocity of the gas as a function of the rotation. to 16 km (Kervella et al., 2016). This con- separation from the centre of rotation. We figuration provided the highest possible determined that this maximum velocity From the measured mass of L2 Pup, angular resolution currently achievable by profile closely follows Kepler’s law up to a stellar evolution models predict that its ALMA, with a beam size of only 15 mas. radius of 5–6 au from the star. Figure 4 age is ~10 Gyr. The mass, radius and It is interesting to remark that this resolu- (lower left and right panels) clearly shows pulsation period are all consistent with tion matches very well that of SPHERE/ the two rotation regimes: Keplerian within a main sequence mass identical to that ZIMPOL in the visible (16–20 mas). We the inner 5 au (that is, v ~ R–1/2), and sub- of the Sun. The missing third of a solar –0.85 selected velocity resolutions of 100 to Keplerian beyond 6 au (v ~ R ). A mass has been lost by L2 Pup during its 400 m s–1 for the molecular line spectral smooth transition is observed between 5 evolution. The extraordinary coincidence windows, corresponding to a spectral and 6 au. From the Keplerian motion of of having a Sun-like AGB star in the close resolution of R ~ 1 000 000. This power- the inner 5 au, we could determine with vicinity of the Sun thus provides us with ful combination of very high spatial and very high accuracy (± 6.6 %) the present a privileged preview of the very distant spectral resolution is permitted by the mass of the AGB star, finding that it is future of our own star.

22 The Messenger 167 – March 2017 29 Figure 4. Upper left: SiO(ν = 0, J = 8–7), ν0 = 342.9805 GHz ZIMPOL NR-band (645 nm) 0.3 0.3 ALMA integrated intensity image in the 29SiO (ν = 0, J = 8–7) molecular line. The dark spot 0.2 0.2 on the star is caused by gas absorption along ) ) the line of sight. Upper right: ZIMPOL image in 0.1 0.1 R-band at the same seconds seconds scale. Lower left: Posi- rc rc tion-velocity diagram (a (a et et (PVD) constructed from 0.0 0.0 fs fs the east-west pseudo-

of slit displayed in the n of on io

ti upper left panel. Lower –0.1 –0.1 right: PVD in logarithmic velocity and radius Declina Declin at scales to show the different power law –0.2 –0.2 regimes of the velocity profile. The domain and positions of various fea- 0.00 0.19 0.38 0210000 00000 tures are indicated –0.3 –0.3 according to the legend. 0.3 0.20.1 0.0–0.1–0.2 –0.3 0.3 0.20.1 0.0–0.1–0.2–0.3 The envelope of the Right ascension offset (arcseconds) Right ascension offset (arcseconds) maximum velocity profile 30 defines the central star mass, and the inflection 40 29SiO(ν = 0, J = 8–7) Background: West points corresponding to the inner edge of the ν0 = 342.9805 GHz 30 dust disc are shown for 20 25 the east and west edges. 20 )

10 ) –1

–1 15 s m s m (k (k

.0 0 ty 10 loci Ve y — 33 locit

Ve –10 5

Photosphere Inner rim –20 Companion (ALMA) M sin i = 0.653 ± 0.011 M ๬ V ≈ Rα with α = –0.85 ± 0.06 East inﬂection –5 0510 15 20 West inﬂection –30 0.3 0.20.1 0.0 –0.1 –0.2 –0.3 0.5 1251020 Position offset on sky (arcseconds) Radius (au)

A candidate planet orbiting in the disc of We estimated the mass of the companion convert this offset into a mass of 12 ±

L2 Pup by comparing the position of the centre 16 MJup for this companion, which corre- of rotation of the molecular disc and the sponds to a planet or a low mass brown The ALMA data in the continuum showed position of the continuum emission peak. dwarf. the presence of an excess of emission The centre of rotation of the molecular in the western wing of the disc (Figure 5), disc is very well defined from the ALMA We also detected excess emission in the contributing 1.3 % of the central star’s PVD (Figure 4), and it corresponds to the PVD of the molecular lines (ν = 0, flux. This emission coincides almost centre of gravity of the mass enclosed by J = 3–2) of 12CO and 13CO at the location perfectly with the secondary source the disc. The continuum emission peak of the candidate planet, at a velocity of –1 L2 Pup B detected with SPHERE/ZIMPOL provides the position of the AGB star. We 12 km s (Figure 6). We propose that this one year before the ALMA observations. determined that the two points are coin- emission comes from the extended

This continuum emission could be pro- cident within 0.55 ± 0.75 mas. As we molecular envelope accreted by L2 Pup B duced by a dusty envelope or by an know the mass of the central star and the from the wind of the AGB star. This

accretion disc surrounding L2 Pup B. current separation of L2 Pup B, we can measured velocity is consistent with the

The Messenger 167 – March 2017 23 Astronomical Science Kervella P. et al., Evolved Star L2 Puppis as a Portrait of the Future Solar System

line-of-sight projection of the velocity Figure 5. Composite view of L Pup in visible vector of a planet in circular Keplerian 2 light (ZIMPOL image in revolution at a radius of 2.4 au from a the R-band, blue col- 0.65 M⊙ central star, that is, with an ours) and ALMA contin- orbital period of 5 years. uum (orange colours). Plume The central star light has been subtracted from This candidate planet is, to our knowl- the ALMA image to bet- edge, the first planet whose emission ter show the companion is detected with ALMA. We also observe object. The size of the a signature at 6 au in the PVD that may star's photosphere is represented to scale. be linked to the plume #1 detected in The white circle in the the ZIMPOL images (yellow arrow in Fig- bottom left corner rep- ure 6). resents the resolution of Red Giant ALMA candidate planet the image (beam size).

The persistence of L2 Pup B between the ZIMPOL and ALMA observations is an indication that this is a compact object rather than a coreless aggregate of gas and dust. The strong Keplerian shear and the radiation pressure would very 5 au quickly blow such a clump into the dust 0.1ೀ disc (R > 6 au). Moreover, the presence of a plume originating from the position of L2 Pup B and launched perpendicular companion. Figure 7 shows our hypothe- (Khouri et al., 2016) and W Hya (Ohnaka to the dust disc plane is an indication sised structure of the detected features in et al., 2016), although they are at a com- that accretion is occurring. Such a possi- the L2 Pup system. We propose that the parable stage of their evolution to L2 Pup, bility is plausible, as the Roche lobe of a large dust loop observed at 4 µm in the do not host axially symmetric circum planet embedded in the dust- and gas- NACO images is created by dust conden- stellar structures but irregular, mostly rich environment surrounding L2 Pup will sation in the shadow of L2 Pup B. The spherical envelopes. We suggest that the sweep up a considerable volume and highly collimated plume is ejected from a axial geometry of the envelope of L2 Pup therefore accrete a significant quantity of putative accretion disc surrounding the is due to the presence of its companion. material. planet. Its biconical shape is also strongly evoca- tive of the bipolar planetary nebulae, and

The presence of a candidate planet orbit- Compared to other AGB stars observed L2 Pup may hold the key to demonstrat- ing L2 Pup provides a remarkable test at high angular resolution, the morphol- ing the link between binarity (including case to observe the interactions between ogy of the circumstellar disc of L2 Pup sub-stellar companions) and bipolarity of the evolved star’s wind and a low-mass stands out as remarkably singular. R Dor planetary nebulae.

12CO(ν = 0, J = 3–2) 13CO(ν = 0, J = 3–2) Companion (SPHERE) 30 Inner rim 30 –55 1 5 10 Companion (ALMA) 0 5 Photosphere M sin i = 0.653 M 25 ๬ 25

20 20 Figure 6. Emission of L2 Pup B in two CO ) ) molecular isotopologue –1 –1 12 s s lines ( CO to the left 15 15 13 m m and CO to the right) in (k (k position-velocity dia- y y grams with logarithmic ocit ocit l l velocity and radius Ve Ve 10 10 scales. The emission from the east wing of the disc has been subtracted. The positions of various key features are indicated in the legend, cf. Figure 4. The yellow arrow marks a 5 5 feature tentatively 0.5 11250 0.51 2510 ascribed to the Plume 1 Radius (au) Radius (au) (cf., Figure 3).

24 The Messenger 167 – March 2017 Figure 7. Proposed Lopez et al., 2014; Millour et al., 2016) will configuration of the dust enable milliarcsecond spectro-imaging of disc of L2 Pup and its candidate planet is the photosphere and structures present shown from a pole-on around the star (plumes, loop, compan- (upper) and equator-on ion). We plan to develop the observations (lower) perspective. of L2 Pup with these new instruments to monitor its pulsation cycle and its close- in molecular envelope (the molsphere, located within 1–3 stellar radii). The inter-

m action of the molsphere with the orbiting ri r planet L2 Pup B may be an important Inne ingredient in the accretion of gas. v v0 B (ALMA, 2015.84) The forthcoming Extremely Large Tele- A scope (ELT) will provide an angular resolution of 60 mas at 10 µm, 12 mas at B (ZIMPOL, 2014.93) 2.2 µm and 3 mas in the visible. Observ-

ing L2 Pup with the ELT will be easy: it is very bright (mV ~ 7.5, mK ~ –2), and thus provides an excellent natural guide

on star for adaptive optics wavefront sens- ti ing. With its 0.4 arcsecond extension, the ansi

R R Tr circumstellar disc is easily resolved spa- 0 B au tially, and high-resolution spectroscopy 0 2468 10 12 will provide a Doppler map of the molecular envelope. The interactions of the Keplerian Sub-Keplerian Earth candidate planet with the dust disc and the wind of the central star will thus be observable in very fine detail, revealing the accretion of a stellar wind onto a planetary-mass object.

Loop As an older sibling of our Sun, and thanks Plum to the powerful existing and foreseen

e high angular resolution instrumentation

available at the VLT and ALMA, L2 Pup will undoubtedly continue to surprise us in the coming years with key discoveries pertinent to the distant future of the Solar System.

A References B Bedding, T. R. et al. 2002, MNRAS, 337, 79 Dullemond, C. P. 2012, Astrophysics Source Code Library, 1202.015 Eisenhauer, F. et al. 2011, The Messenger, 143, 16 Prospects for future observations determine its mass from its Keplerian Homan, W. et al. 2017, A&A, submitted Kervella, P. et al. 2014a, A&A, 564, A88 velocity amplitude. Kervella, P. et al. 2014b, A&A, 572, A7 The longest ALMA baselines of 16 km Kervella, P. et al. 2015, A&A, 578, A77 combined with the shortest wavelengths Optical interferometry with the Very Large Kervella, P. et al. 2016, A&A, 596, A92 (Bands 9 and 10) will soon give access Telescope Interferometer (VLTI) commis- Khouri, T. et al. 2016, A&A, 591, A70 Lopez, B. et al. 2014, The Messenger, 157, 5 to an angular resolution ~ 6 mas. Assum- sioning instrument VINCI has been used Millour, F. et al. 2016, Proc. SPIE, 9907, 99073 ing a mass of 12 MJup for L2 Pup B, its by Kervella et al. (2014a) to measure the Ohnaka, K., Weigelt, G. & Hofmann, K.-H. 2016, Roche lobe has a diameter of about angular diameter of the central AGB star A&A, 589, A91 0.6 au, or 10 mas. This means that it will of L Pup. The VLTI second-generation Ohtomo, Y. et al. 2014, Nature Geoscience, 7, 25 2 Sparks, W. B. et al. 2008, AJ, 135, 605 be possible to resolve the putative accre- instruments GRAVITY (Eisenhauer et al., van Leeuwen, F. 2007, A&A, 474, 653 tion disc around L2 Pup B (particularly 2011) and the Multi AperTure mid-Infrared Veras, D. 2016, Royal Society Open Science, 3, 150571 in CO molecular emission) and directly SpectroScopic Experiment (MATISSE: Wiesemeyer, H. et al. 2009, A&A, 498, 801

The Messenger 167 – March 2017 25 Astronomical Science DOI: doi.org/10.18727/0722-6691/5005

Supernova 1987A at 30

Jason Spyromilio1 ranged across astroparticles and all made famous by HST, Chandra and Bruno Leibundgut1 wavelengths of the electromagnetic ATCA images (see Figure 1, left), is readily Claes Fransson2 spectrum, then one might consider one visible in images from NAOS-CONICA Josefin Larsson2 had found the perfect source. (NACO), and the Spectrograph for INtegral Katia Migotto2 Field Observations in the Near-Infrared Julien Girard1 SN 1987A is just such a heavenly object! (SINFONI) as well (Larsson et al., 2016). That it is circumpolar for the more south- Figure 1 right shows a very recent NACO ern astronomical sites adds to its opti- image at 2.15 μm (Ks-band). The flux in 1 ESO mality. Located in the Large Magellanic the Ks-band is dominated by Brackett-γ 2 Department of Astronomy, The Oskar Cloud (LMC), it is near enough to be emission at 2.165 µm illuminated from the Klein Centre, Stockholm University, resolved, yet far enough to not be a outside. The illumination of the ring at Sweden threat, along an almost unextinguished the earliest times, by the ultraviolet (UV) line of sight, in a relatively uncluttered light emerging as the shock broke the part of its host galaxy. It is evolving on surface of the progenitor star, was used Thirty years on, SN 1987A continues to a human timescale. Many articles on to determine a geometric distance to the develop and, over the last decade in 1987A have appeared in the pages of LMC and remains one of the anchors of particular, has: revealed the presence of The Messenger over the years and there- the extra-galactic distance ladder. The a large centrally concentrated reservoir fore we will not dwell here on the past ring illumination also provided the first of dust; shown the presence of molecu- but rather focus on the current state and evidence of the radiation from the shock lar species within the ejecta; expanded ponder an exciting future. A comprehen- break-out, lasting only a few minutes but such that the ejecta structure is angu- sive review (McCray & Fransson, 2016) with a temperature of about a million larly resolved; begun the destruction of appeared recently and covers SN 1987A degrees. the circumstellar ring and transitioned over the past 10 000 days. to being dominated by energy sources Later, when the fastest ejecta, moving external to the ejecta. We are partici- Despite fading by seven orders of magni- at ~10 % of the speed of light, reached pating in a live experiment in the creation tude from its peak, the supernova and its the ring, the shocked gas emitted brightly of a supernova remnant and here the surroundings remain readily observable. at wavelengths from radio to X-ray. recent progress is briefly overviewed. Lengthy exposure times are still necessary Recently, observations from HST have Exciting developments can be expected to study the details and, critically, the time- been used to show that the ring is begin- as the ejecta and the reverse shock scales over which the supernova changes ning to suffer from the effects of the ejecta continue their interaction, the X-rays remain of order half a year (approximately colliding into it (Fransson et al., 2015). It penetrate into the cold molecular core the light travel time of the ejecta at this will take a while, but the ring is currently and we observe the return of the mate- epoch); therefore continued vigilance is being destroyed. A simple extrapolation rial into the interstellar medium. We needed. ESO, together with the Hubble estimates this process will be complete by anticipate that the nature of the remnant Space Telescope (HST) and the Australia ~ 2025. However, new spots of emission of the leptonisation event in the centre Telescope Compact Array (ATCA), are the outside the ring have appeared and con- will also be revealed. sole observatories that, thanks to the evo- tinued observations may yet provide sur- lution of their observing capabilities, have prises about the surrounding structure. provided the necessary continuous ultra- We get to watch in real time as a shock In the preface to the first SN 1987A con- violet/optical/near-infrared/radio coverage wave with well-defined characteristics ference thirty years ago (Danziger, 1987), of the supernova, and fortunately the fire- impinges on a well-understood structure Lodewijk Woltjer, then Director General of works are still continuing. Together with (both in density and composition); a text ESO, welcomed the participants with the similar monitoring by the Chandra and book illustration of shock theory. prescient statement “It is very well possi- X-ray Multi-Mirror Mission (XMM-Newton) ble that […] SN 1987A will remain observ- space telescopes in X-rays, these facili- able for thousands of years to come.” ties have provided a nearly complete Radioactivities multi-wavelength coverage of the development of the supernova. These tele- Inside the ejecta, radioactive species Introduction scopes are providing a legacy dataset for freshly synthesised in the explosion pro- this object that cannot be repeated. vide gamma rays and energetic positrons If an observational astronomer was that deposit their energy into the ejecta, allowed to pick the parameters of the The progenitor star (Sanduleak –69°202) provided they do not escape. Which iso- object of study, then ideally the angular of SN 1987A cleared a volume around topes are present, and how much of size would be matched to the resolution itself, sweeping-up material blown off in each, are critical to our understanding of of the telescope, the dimensions of the earlier evolutionary stages (about the emerging spectrum. The isotope mix physical processes would be matched 8000 years ago) into an hour-glass struc- also places limits on the mass cut (the to the angular size and the variability ture dominated by an equatorial ring. This mass coordinate in the proto-neutron star matched to the proposal cycles for tele- structure, first observed with the New where the ejection starts and the collapse scope time. If, in addition, the physics Technology Telescope (NTT) in 1989, and ends) and provides a measure of the

26 The Messenger 167 – March 2017 Figure 1. Left: combined HST (green), Chandra (blue) and ALMA (red) image of SN 1987A. Right: NACO data taken in January 2017 in the Ks-band. The ejecta emission in the centre of the ring is well resolved in both images; the short axis of the ring projects to 1 arcsecond on the sky. The west side of the ring can now be seen to be significantly brighter than the east side.

nucleosynthetic yield of the supernova. ARray (NuSTAR) detection (Boggs et al., core. This distribution is one of the main The presence of 56Ni (source of 56Fe) had 2015) and the INTErnational Gamma-Ray diagnostics of the explosion dynamics long been confirmed in SN 1987A, as Astrophysics Laboratory (INTEGRAL) during the first seconds. had 57Co. Theory predicted that 44Ti detection by Grebenev et al. (2012) of should also be made in the explosion of hard X-ray lines from 44Ti. Observations supernovae. Combining Very Large Tele- with SINFONI (Kjaer et al., 2010; Larsson Shocks scope (VLT) and HST spectra with time- et al., 2016) and HST (Larsson et al., dependent non-local thermodynamic 2011) have revealed a complex structure While the forward shock moves through equilibrium (LTE) radiative transfer calcu- of emission from atomic species that, in the ring, slowing down the ejecta and lations, it was determined that 44Ti had some cases, are collocated with the radi- accelerating the ring material, the reverse taken the role of key energy supplier to oactive species and in others are illumi- shock is formed by the supernova ejecta the supernova eight years after the explo- nated by external sources. In particular, hitting the decelerated medium behind sion (Jerkstrand et al., 2011). the SINFONI observation of the 1.644 µm the forward shock. The reverse shock is [Si I] + [Fe II] line gives a three-dimen- formed in successfully slower and denser It was consequently exciting to see both sional view of the 44Ti distribution in the regions in the supernova ejecta. the Nuclear Spectroscopic Telescope ejecta, responsible for powering the inner The supernova ejecta are being exposed from the outside to X-rays from the ring 120 Figure 2. The light interaction and at some point during the curve of the super- supernova’s teenage years the dominant nova over the past 5000 days. Different source of energy became the conversion 100 components and of kinetic energy from the supernova wavelengths are iden- ejecta with the surroundings. Quite ele- tified. The dimming of gantly, just as the radioactive elements ) 80 the ring in optical –1 whose decay had powered the emission s emission and the

g brightening of the of the junior supernova exponentially er

emission from the 3 decreased, the X-rays from the interaction –1 60 Ring: 0.5–8 keV ejecta, consequent 0 Ejecta: R-band × 150 with the inner ring provided the energy for

(1 on the input of energy

from the reverse an outside-in look at the ejecta. These

Flux shock, are evident. X-rays are mainly absorbed in the hydro- 40 Ring: [O III] × 300 gen rich envelope and the metal core is still powered by decay of 44Ti.

20 The different emission sites (ionised but Ring: R-band × 5 unshocked ring material, shocked ring gas, reverse shock, inner supernova 0 4000 6000 8000 10 000 ejecta) account for the vastly different Days since explosion velocities, and are easily separated in the

The Messenger 167 – March 2017 27 Astronomical Science Spyromilio J. et al., Supernova 1987A at 30

–13 The ejecta continue to be observed –13 Hα unshocked ring across the optical and near-infrared spectral region. SINFONI with adaptive Hα [N II] optics has been critical in providing a view of the near-infrared emission at a –13.5 –14 [N II] spatial resolution comparable to that of [O I] HST. This work has established the

)] geometry of the emission in the lower –1

Å –14 ionisation lines of [Fe II] and [Si I]. These

–1

s “core” elements play a critical role in

–2 –15 cooling the ejecta while at the same time –14.5 Shocked ring tracing the radioactive energy deposition. rg cm However, the SINFONI data also provided (e –1000 0 1000 x [S II] us with the ability to find previously unde- He I [Flu tected molecular gas. –15 lo g Before construction of the VLT had even been approved, the discovery of hot –15.5 (2000 K) molecular emission (CO and Ejecta Hα SiO) from within the ejecta of 1987A initi- ated the discussion of supernova chem- –16 Reverse shock istry. Chemical models also predicted Ejecta [O I] formation of molecular hydrogen (Culhane –15 –10–50 51015 & McCray, 1995). H2 is notoriously shy Velocity (1000 km s–1) and challenging to detect in the part of the spectrum approaching the thermal Figure 3. The UVES spectrum of SN 1987A around The dominant feature of the velocity infrared, and therefore it was a pleasant the Hα line in different zooms; spectrum taken in profile from the whole supernova shown confirmation to detect the emission January 2012. The UVES slit covers the whole –1 supernova, sampling the emission from all compo- in Figure 4 is the ~ 500 km s emission (Fransson et al., 2016) in SINFONI data nents; see text for details. from the shocked ring, seen in Hα some 20 years after the explosion. and the [N II] lines either side of it. The Except for its very presence, the fact that optical and infrared spectrum of the narrow feature on top of the broader the observed distribution reaches almost supernova. The UV-Visual Echelle profile is emission from the ionised ring to the centre means that hydrogen was Spectrograph (UVES) spectroscopy gas at the systemic velocity of the super- mixed by the Rayleigh-Taylor instabilities complements the HST imaging by provid- nova, + 287 km s–1. Over a range of shortly after the explosion, as predicted ing separation of the different velocity 10 000 km s–1 and at a flux level less than by explosion models (for example, components, and is perfectly suited both 1 % of the peak of the ring emission, we Wongwathanarat et al., 2015). in wavelength coverage and resolution see a strong box-like emission of Hα. (see Figure 4 for the different velocity This is emission from the supernova components in the Hα region). Spectra ejecta passing through the reverse Dust and molecules such as this have allowed us to follow shock. The emission from the inner core the evolution of both the ring and ejecta can be seen as the rising blue emission As new facilities come online, SN 1987A emission continuously. for velocities less than about 2500 km s–1. is not only a natural target but also a

Figure 4. Left: SINFONI spectral image in the molecular hydrogen line H2 2.41 μm at 2.40 µm (from Fransson et al., 2016). The bright ring is the continuum emission from the shocks and is not related to the molecular hydrogen in the inner ejecta. Right: 3D dis- Y tribution of the 1.64 µm [Si I] + [Fe II] line from SINFONI. The ring is shown for reference and the tick marks on the box are at steps of 1000 km s–1.

X Z

28 The Messenger 167 – March 2017 Wavelength remnant before the reverse shock dis- 1 cm 3 mm 1 mm 300 μm 100 μm turbs the environment. We will need to remain vigilant to see whether the dust and molecules survive or are destroyed. Supernovae are certain to be prolific 102 polluters of the early Universe in metals. Whether they also contribute dust and ALMA: central ejecta molecules to the mix, we will see in the experiment taking place before our telescopes. ) Jy ALMA: torus The future (m ν

F 1 10 What can we expect for the future? The holy grail is certainly the nature of the compact object in the centre. The length of the neutrino burst indicated the formation of a neutron star, but with later fall- back it is also possible that a black hole could have been formed. ATCA has been giving us a detailed view of the material around the supernova (Potter et al., 2009) 10 0 30 GHz100 GHz300 GHz 1 THz3 THz and combining these radio data with Frequency ALMA mm/sub-mm data provides an interesting constraint set for the presence Figure 5. ALMA's angular resolution permits the the cold dust with the inner ejecta of of a plerion, a region ionised by the separation of the continuum dust emission from the 1987A (Indebetouw et al., 2014; see Fig- strong magnetic field of the neutron star, synchrotron power law radiation resulting from shocks in the ring. The measurements shortward of ure 5). The mass of the dust, however, in the centre of the remnant (Zanardo et 400 µm are from Herschel (Matsuura et al., 2011) remains “stubbornly high”, above 0.5 M⊙ al., 2014). Higher angular resolution and APEX (Lakicevic et al., 2012) At low frequencies (Matsuura et al., 2015). If the dust sur- observations with ALMA will help greatly. data come from ATCA (Potter et al., 2009; Zanardo vives travelling through the reverse et al., 2014). From Indebetouw et al. (2014). shock, then core-collapse supernovae From X-ray observations there is a strong may be a significant contributor to the upper limit to the luminosity in the source of new understanding. The dust budget in the early Universe. 3–10 keV band of 3 × 1033 erg s–1 (Frank Spitzer Space Telescope observed the et al., 2016). The absorption of the X-rays supernova out to 30 µm and detected the The ALMA spectra provided further by the ejecta may, however, still be large presence of warm dust. Observations excitement in that, in addition to the dust (Fransson & Chevalier, 1987; Orlando et with the Gemini South telescope and the observations, they revealed strong emis- al., 2015), although this decreases rapidly VLT in the 10 µm band showed that the sion from CO 2–1 and SiO 5–4 transi- with the expansion of the ejecta. The thermal infrared emission comes from the tions. Combined with a detection by clumpiness of the ejecta, as revealed by equatorial ring. In 2010 the Herschel sat- Herschel of the CO 6–5 and 7–6 transi- SINFONI and ALMA, is the main uncer- ellite observed the supernova in the far tions, the temperature and mass determi- tainty. The optical/infrared may also pro- infrared and detected an enormous nation could be refined by Kamenetzky vide an interesting window, since any excess of emission longward of 100 µm et al. (2013). Approximately 0.01 M⊙ of absorbed X-rays may be reprocessed (Matsuura et al., 2011). Contemporane- CO emits at a temperature of ~ 20 K and into this wavelength range. The infrared ously, Lakićević et al. (2012) used APEX at an expansion velocity of 2000 km s–1. sensitivity of the James Webb Space Tel- to detect emission from the supernova at It remains to be seen whether this is the escope (JWST) and the superior spatial 300 and 870 µm. Combining the flux with same CO that was detected at 2000 K resolution of the Extremely Large Tele- models of dust, Matsuura et al. (2011) and 2000 km s–1 during the supernova’s scope (ELT), will be especially exciting concluded that between 0.1 and 1 M⊙ of first year or represents new formation. here. With the new and old facilities, we dust formed in the supernova. will, hopefully, during the coming decade Fascinating new ALMA observations at reveal whether the leptonisation event Given the angular resolution of Spitzer high angular resolution are in the process that was responsible for the neutrinos and Herschel, the location of the cold of being published (Abellan et al., 2017, ended in a neutron star or a black hole. dust remained uncertain. Observations in submitted). The cold CO and SiO in the 2013 with ALMA at 1 mm and 450 µm at centre of the supernova are seen to be As for the ejecta and circumstellar an angular resolution of ~ 0.5 arcseconds separated into clumps. These are unique medium, we are already seeing the proved the unambiguous association of observations of the birth of a supernova decaying ring emission. The shock wave,

The Messenger 167 – March 2017 29 Astronomical Science Spyromilio J. et al., Supernova 1987A at 30

however, continues out into the circum- ring have also been found. The neutron the sites. They have all contributed through their stellar medium beyond the ring, and will star has so far defied detection. expertise and enthusiasm to generating this beautiful and unique data set. We also want to thank the time hopefully reveal more of the several solar allocation committees over the decades who have masses of material thought to have been There have indeed also been great sur- recognised the uniqueness of the supernova and lost by the progenitor star. The mass of prises. Tracing the explosion mechanism have supported this research. the ring is only ~ 0.06 M . The X-ray by directly observing the geometry of the ⊙ The authors thank the current editor, himself a emission is expected to decay more element distribution in the inner ejecta naked eye observer of SN 1987A, for improving slowly than the optical ring emission. It confirms the non-spherical explosion the article and wish the next editor a Galactic will therefore continue to illuminate more models. The illumination of the inner supernova for herself. and more of the ejecta, and thus also ejecta by X-rays from the ring is a new give a new view of the abundance and feature in the development of SN 1987A. References hydrodynamic structure of the ejecta. The It provides a novel and unexpected win- supernova will then gradually transform dow on parts of the ejecta that have so Boggs, S. E. et al. 2015, Science, 348, 670 into a supernova remnant similar to other far been unobservable. The molecules in Culhane, M. & McCray, R. 1995, ApJ, 455, 335 Danziger, I. J. 1987, Proc. ESO Workshop on young remnants. We can follow this in the inner ejecta were predicted early on SN 1987, ESO, Garching real time for hundreds of years, perhaps and have finally been found. ALMA, with Frank, K. A. et al. 2016, ApJ, 829, 40 longer, as suggested by Lo Woltjer. In all its first observations, together with Fransson, C. & Chevalier, R. A. 1987, ApJ, 322, 15 these aspects ESO can continue to play Spitzer and Herschel, have told us more Fransson, C. et al. 2007, The Messenger, 127, 44 Fransson, C. et al. 2015, ApJ, 806, L19 a leading role. about the dust in SN 1987A than we Fransson, C. et al. 2016, ApJ, 821, 5 could have guessed two decades ago. Grebenev, S. A. et al. 2012, Nature, 490, 373 Ten years ago we were already musing The reverse shock has been firmly Indebetouw, R. et al. 2014, ApJ, 782, L2 about the future development of SN 1987A observed and adds another important Jerkstrand, A. et al. 2011, A&A, 530, A45 Kamenetzky, J. et al. 2013, ApJL, 773, L34 (Fransson et al., 2007). We predicted aspect to the evolution of the supernova. Kjaer, K. et al. 2010, A&A, 517, 51 exciting events — the destruction of the Lakićević, M. et al. 2012, A&A, 541, L1 inner ring and the illumination of material Larsson, J. et al. 2011, Nature, 474, 484 outside the ring. We were also hoping Larsson, J. et al. 2016, ApJ, 833, 147 Matsuura, M. et al. 2011, Science, 333, 6047 Acknowledgements to find the compact remnant inside Matsuura, M. et al. 2015, ApJ, 800, 50 SN 1987A and hopefully other surprises. McCray, R. & Fransson, C. 2016, ARAA, 54, 19 It is a pleasure to thank all the staff at the various Orlando, S. et al. 2015, ApJ, 810, 168 The ring has started to fade, indicating observatories and in particular those involved in the Potter, T. M. et al. 2009, ApJ, 705, 261 that it will be destroyed in the near future, Paranal and ALMA operations, both in preparing the Zanardo, G. et al. 2014, ApJ, 796, 82 and the first traces of material beyond the observations in Garching and in executing them on

A wide-field image (about 4 degrees in extent) of the Large Magellanic Cloud and 30 Doradus taken by the ESO 1-metre Schmidt telescope in 1986, before the appearance of SN 1987A.

30 The Messenger 167 – March 2017 Astronomical Science DOI: doi.org/10.18727/0722-6691/5006

VANDELS: Exploring the Physics of High-redshift Galaxy Evolution

Ross McLure1 mately the same as it was less than a varying degrees of hard evidence and Laura Pentericci2 billion years after the Big Bang (i.e. z ~ 7), speculation, active galactic nuclei (AGN) and that in the intervening period the Uni- feedback, stellar winds, merging and and the VANDELS team verse was forming stars about ten times environmental-/mass-driven quenching more rapidly. However, despite this it is have all been widely discussed in the still perfectly plausible to argue that the literature (see Fabian, 2012 and Conselice, 1 Institute for Astronomy, University peak in cosmic star formation history 2014 for reviews). It seems clear that of Edinburgh, Royal Observatory occurred anywhere in the redshift interval quenching must be connected to the Edinburgh, United Kingdom 1.5 < z < 3.5, an uncertainty of two and interplay between gas outflow, the inflow 2 INAF, Osservatorio Astronomico di a half billion years. Moreover, the results of “pristine” gas, the build-up of the Roma, Monteporzio, Italy of the latest generation of semi-analytic mass-metallicity relation and morpho and hydro-dynamical galaxy simulations logical transformation. However, to date, (for example Somerville & Davé, 2015) the relative importance of, and intercon- VANDELS is a new ESO spectroscopic demonstrate that, from a theoretical per- nections between, the different underly- Public Survey targeting the high-redshift spective, even reproducing the evolution ing physical mechanisms remain unclear. Universe. Exploiting the red sensitivity of the cosmic star formation density can of the refurbished VIMOS spectrograph, be problematic. Within this context, a series of spectro- the survey is obtaining ultra-deep opti- scopic campaigns with the Very Large cal spectroscopy of around 2100 galax- Over the last decade it has become Telescope (VLT) and the VIsible Multi ies in the redshift interval 1.0 < z < 7.0, clear that the majority of cosmic star for- Object Spectrograph (VIMOS), such as with 85 % of its targets selected to mation is produced by galaxies lying on the VIMOS Very Deep Survey (VVDS; be at z ≥ 3. The fundamental aim of the the so-called main sequence of star for- Le Fèvre et al., 2005), the COSMOS survey is to provide the high signal- mation (Noeske et al., 2007). The main spectroscopic survey (zCOSMOS; Lilly to-noise spectra necessary to measure sequence is a roughly linear relationship et al., 2007) and the VIMOS Ultra Deep key physical properties such as stellar between star formation rate (SFR) and Survey (VUDS; Le Fèvre et al., 2015), population ages, metallicities and out- stellar mass, the normalisation of which have played a key role in improving our flow velocities from detailed absorption- increases with lookback time. Galaxies understanding of galaxy evolution, pri- line studies. By targeting two extraga- lying well above the main sequence can marily through providing large numbers lactic survey fields with superb multi- be considered to be starbursts, while of spectroscopic redshifts over wide wavelength imaging data, VANDELS those falling well below the main sequence fields. The VANDELS survey is designed will produce a unique legacy dataset for are passive, or quenched. to complement and extend the work of exploring the physics underpinning these previous campaigns by focusing on high-redshift galaxy evolution. The evolution in the normalisation of ultra-long exposures of a relatively small the main sequence over the last 10 Gyr number of galaxies, pre-selected to lie is now relatively well established, with at high redshift using the best available Background the average SFR at a given stellar mass photometric redshift information. increasing by a factor of about 30 Understanding the formation and evolu- between the local Universe and redshift tion of galaxies, from the collapse of z = 2 (for example, Daddi et al., 2009). The survey the first gas clouds at early times to the However, at higher redshifts the evolution assembly of the detailed structure we of the main sequence is still uncertain, The VANDELS (Proposal ID 194.A-2003) observe in the local Universe, remains the despite a clear theoretical prediction that survey is repeatedly targeting a total of key goal of extragalactic astronomy. it should mirror the increase in halo gas eight overlapping VIMOS pointings (see Despite the immense challenge, the last accretion rates (for example, Dekel et al., Figure 1), four in the United Kingdom 15 years have been a period of unprece- 2009). Depending on their assumptions InfraRed Telescope (UKIRT) Infrared dented progress in our understanding of regarding star formation histories, metal- Deep Sky Survey (UKIDSS) Ultra Deep the basic demographics of high-redshift licity, dust and nebular emission, different Survey (UDS) and four in the Chandra galaxies. Indeed, thanks largely to the studies find that at a given stellar mass Deep Field South (CDFS). VANDELS profusion of deep, multi-wavelength sur- the increase in average SFR between observations are exclusively performed vey fields, we now have a good working z = 2 and z = 6 is anything from a factor using the medium resolution (MR) grism knowledge of how the galaxy luminosity of about two (for example, González et al., + GG475 order-sorting filter, which pro- function, stellar mass function and global 2014), to a factor of about 25 (for exam- vides medium resolution (R ~ 700) spectra star formation rate density evolve with ple, de Barros et al., 2014). covering the wavelength range 4800– redshift (see Madau & Dickinson, 2014 for 10 000 Å at a dispersion of 2.5 Å pixel–1. a recent review). Moreover, although the decline in the global star formation rate density over the Each of the eight pointings is observed As a consequence, we can now be last 10 Gyr has been well characterised, four times, each pass receiving 20 hours confident that the star formation rate the primary physical drivers responsible of on-source integration. Using a nested density we observe locally is approxi- for this quenching remain uncertain. With slit allocation strategy, targets are allocated

The Messenger 167 – March 2017 31 Astronomical Science McLure R. et al., VANDELS: Exploring the Physics of High-redshift Galaxy Evolution

either 20, 40 or 80 hours of integration, depending on their brightness. In total, 5 arcmin VANDELS has been allocated 640 hours 1 1 of on-source observing time, all of which –5°04ಿ is being obtained in Visitor Mode on 2 2 the VLT between August 2015 and Janu- ary 2018. 08ಿ

In order to justify such a large investment ) of observing time, VANDELS is deliber- 000 ately focused on two of the best legacy 2 (J fields for studying the high-redshift Uni- 12ಿ

verse. Crucially, both the UDS and CDFS at ion are covered by deep optical–near-infrared 1 1 Hubble Space Telescope (HST) imaging Declin provided by the CANDELS survey (Grogin 2 2 16 et al., 2011). In addition, both UDS and ಿ CDFS are covered by ultra-deep imaging with the Spitzer Space Telescope, HST near-infrared grism spectroscopy from the public 3D-HST survey (Brammer 20ಿ et al., 2012) and the deepest available Y+K-band imaging from the HAWK-I Ultra Deep Survey (HUGS; Fontana et al., 2014). 18 m 2h17 m Right ascension (J2000) The fundamental science goal of VANDELS is to move beyond simple redshift acquisition and obtain a spectroscopic dataset deep enough to study the 5 arcmin astrophysics of high-redshift galaxy evo- 4 4 lution. The spectroscopic targets are all –5°04ಿ pre-selected using high-quality photo- 3 3 metric redshifts, the vast majority being drawn from one of three main categories: bright star-forming galaxies, higher red- 08ಿ shift star forming galaxies and passive ) galaxies. 000 2 (J

Firstly, VANDELS is targeting a sample 12ಿ of more than 400 bright (HAB ≤ 24, IAB ≤ at ion 25 mag.) star-forming galaxies in the 4 4

redshift range 2.4 < z < 5.5. The spectra Declin 3 3 of these galaxies will cover the required 16 rest-frame ultraviolet (UV) wavelength ಿ range with a signal-to-noise ratio (SNR) high enough to allow the stellar metallicity to be measured. Secondly, the VANDELS survey extends to higher redshifts and 20ಿ fainter magnitudes by targeting a large sample (around 1300) of star-forming galaxies at 3 < z < 7 in the magnitude 18 m 2h17 m range (25 < iAB < 27). Thirdly, to study the Right ascension (J2000) descendants of high-redshift star-forming galaxies, VANDELS also uses rest-frame Figure 1. Illustration of how the four VANDELS imaging area is covered. Outside the central region, UVJ selection (Williams et al., 2009) to VIMOS pointings are organised within the UDS the background image shows the deep H-band target a complementary sample of around survey field. The rectangle indicated by the dashed imaging from the UKIDSS UDS survey. To maximise 300 massive (H ≤ 22.5), passive galax- white line shows the region covered by deep H-band the slit allocation efficiency, targets can be allocated AB HST imaging from the CANDELS survey. The four to slits on quadrants in different overlapping point- ies at 1.0 < z < 2.5. Finally, thanks to VIMOS pointings (labelled 1–4), each with four quad- ings. The four pointings within the CDFS survey the large number of targets that can be rants, are located to ensure that 100 % of the HST fields are organised in a similar fashion.

32 The Messenger 167 – March 2017 G Ca II Ca II allocated on each VIMOS mask, VANDELS -ban Mg Mg Mg Fe II Fe II Fe H is also targeting small samples of rarer H II H K d

δ γ bright systems such as AGN and galaxies I I I 3.0 detected by the Herschel satellite.

The VANDELS observing strategy is 2.5 designed to provide consistently high ) –1 Å SNR continuum detections for the bright –2 2.0 star-forming and passive galaxy sub- cm

samples (see Figure 2 for example spec- –1 s 1.5 tra). For those objects with iAB ≤ 24.5, rg (e

the final 1D spectra will typically provide 8 SNR of 15–20 per resolution element, –1 1.0 10 /

based on total exposure times of 20, 40 λ or 80 hours. For the faintest objects in F 0.5 these sub-samples (IAB ~ 25), the final spectra typically have a SNR ~ 10 per resolution element, based on 80 hours of 0.0 integration. For the faintest (25 < i < 27) AB 5000 6000 7000 8000 9000 targets at z ≥ 3, the VANDELS observing Observed wavelength (Å) strategy is designed to provide a con sistent Ly-α emission-line detection limit N –18 –1 –2 IV Mg He Mg Zn C Fe II Fe II Fe II (5 ) of ~ 2 × 10 erg s cm and a Fe II C III Ni N

σ A III A III IV II II II II iI

continuum SNR of about 3 per resolution I I element. The data reduction and survey 3.0 management of VANDELS are performed within the Easylife system (Garilli et al., 2.5

2012). Easylife is an updated version of ) –1 Å the original VIMOS Interactive Pipeline and Graphical Interface (VIPGI) system –2 2.0 cm and was originally developed to process –1 s the data from the VIMOS Public Extraga- 1.5 lactic Redshift Survey (VIPERS; Guzzo et rg (e

al., 2014). –1

10 1.0 / λ F

Science goals 0.5

As outlined briefly above, current studies 0.0 of high-redshift galaxies are limited by 5000 6000 7000 8000 9000 interrelated and insidious uncertainties in Observed wavelength (Å) the measurements of key physical He Si Si C N parameters such as stellar mass, metal- Fe II Ni Ni A III A III Ly Si Si C II O

IV IV IV IV II II II II II licity, star formation rate and dust attenu- α I ation. The VANDELS survey is specifically 2.0 designed to provide the high-SNR spectra necessary to derive accurate physical ) –1 1.5 Å parameters via absorption line studies, –2 cm 1.0 Figure 2. Example spectra from the VANDELS –1 survey. The top panel shows a redshift z = 1.1303 s passive/quiescent galaxy. The middle panel shows rg (e a bright star-forming galaxy at z = 2.372 and the 8 0.5 –1 bottom panel shows a bright star-forming galaxy at 10 / z = 3.703. Common absorption (dotted lines) and λ emission (dot-dashed lines) features are highlighted. F 0.0 For the type of objects shown, the VANDELS observations are designed to provide spectra with sufficiently high SNRs to allow key physical properties –0.5 (for example, metallicity and outflow velocities) to be 5000 6000 7000 8000 9000 measured on an individual, object-by-object, basis. Observed wavelength (Å)

The Messenger 167 – March 2017 33 Astronomical Science McLure R. et al., VANDELS: Exploring the Physics of High-redshift Galaxy Evolution He Si Si C Fe II C III Ni A III A III Ly Si Si C II

O Figure 3. An illustration of the potential

IV IV IV II II II II α

I within the VANDELS dataset for pro- 3.0 ducing high-SNR stacked spectra. This example shows the stacked spectrum of 100 fainter star-forming 2.5 galaxies in the redshift interval )

–1 3.0 < z < 4.0. Common absorption Å (dotted lines) and emission (dot- –2 2.0 dashed lines) features are highlighted. cm The stacked spectra from VANDELS –1

s will allow key physical properties to 1.5 rg be investigated over a wide dynamic (e

range in redshift, stellar mass and star 9

–1 formation rate. 0 1.0 /1 λ F 0.5

0.0 1200 1300 1400 1500 1600 1700 1800 1900 2000 Rest-frame wavelength (Å) and will therefore have an impact on slopes) will also lead to significantly stand the impact of galactic outflows many areas of high-redshift galaxy evo improved estimates of stellar masses on star formation at z ≥ 2. Measuring lution science. However, the original and SFRs. Importantly, this means that the balance of inflow, outflow and star VANDELS survey proposal was motivated the VANDELS dataset will allow the formation will enable models of the by a small number of key science goals, stellar mass – stellar metallicity relation evolving gas reservoir to be tested and three of which we briefly discuss below. to be studied out to z ~ 5 for the first address the origins of the Fundamental time. Moreover, the improved stellar Metallicity Relation (Mannucci et al., 1. Stellar metallicity and dust attenuation mass and SFR estimates for about 2010). Finally, comparing the outflow Tracing the evolution of metallicity is 1800 spectroscopically confirmed star- velocities of star-forming galaxies with a powerful method of constraining forming galaxies at 2.4 < z < 7.0 will and without hidden AGN (as identified high-redshift galaxy evolution via its also allow accurate calibration of photo- from X-ray emission) will allow the role direct link to past star formation and metric determinations of the evolving of AGN feedback in quenching star sensitivity to interaction (inflow/outflow) stellar mass and SFR functions. formation and the build-up of the red with the intergalactic medium. Moreo- sequence to be investigated. ver, accurate knowledge of metallicity 2. Outflows is essential for deriving accurate star Along with stellar metallicity measure- 3. Massive galaxy assembly and formation rates and breaking the ments, a key science goal for VANDELS quenching degeneracy between age and dust is the study of outflowing interstellar A key sub-component of VANDELS extinction (for example, Rogers et al., gas. It is now becoming increasingly is obtaining deep spectroscopy of 2014). clear that high-velocity outflows may ~ 300 massive, passive galaxies at be ubiquitous amongst star forming 1.0 < z < 2.5. This population holds the Recent studies using stacked spectra galaxies at z > 1, with mass outflow key to understanding the quenching of relatively small samples (for example, rates comparable to the rates of star mechanisms responsible for producing Steidel et al., 2016) have shown that formation (for example, Bradshaw et al., the strong colour bi-modality observed it is possible to derive accurate stellar 2013). Such outflows may be playing at z < 1, together with the significant metallicities from the rest-frame UV a major role in the termination of star evolution in the number density, mor- spectra of galaxies at z ≥ 2, provided formation at high redshift and the phology and size of passive galaxies the spectra have a high enough SNR. build-up of the mass–metallicity rela- observed between z = 2 and the pre- The VANDELS data will allow metal tion. sent day. For the majority of the pas- licities to be measured for hundreds sive sub-sample, the VANDELS spec- of galaxies at 2.4 < z < 5.5, both indi- Crucially, the high-SNR, medium- tra will provide a combination of crucial vidually and via stacking (see Figures 2 resolution, VANDELS spectra will allow rest-frame UV absorption-line informa- and 3) and therefore offers the pros- accurate measurements of outflowing tion and Balmer break measurements. pect of transforming our understanding interstellar medium velocities from Combined with the unrivalled photo- of metallicity at high redshift. high- and low-ionisation UV interstellar metric data available in the UDS and absorption features (for example, CDFS fields, it will be possible to break It is worth noting that the ability to inde- Shapley et al., 2003). The fundamental age/dust/metallicity degeneracies and pendently constrain the stellar metallic- goal is to measure the outflow rate as deliver accurate stellar mass, dynami- ity and dust attenuation (from the ratio a function of stellar mass, SFR, and cal mass, star formation rate, metal of observed to intrinsic UV spectral galaxy morphology, in order to under- licity and age measurements via full

34 The Messenger 167 – March 2017 spectrophotometric spectral energy of the James Webb Space Telescope load via the ESO Science Archive Facility distribution (SED) fitting. (JWST) in late 2018. The opportunity to (SAF). In addition, the VANDELS team are combine ultra-deep optical spectroscopy committed to a regular schedule of data with the unparalleled near-infrared spec- releases (starting with data release 1 in Legacy science troscopic capabilities of the JWST near- June 2017), through which fully reduced infrared spectrograph NIRSpec will make 1D and 2D spectra, plus redshifts and Finally, given that VANDELS is fundamen- VANDELS sources an obvious choice for basic target parameters, will be provided tally a public spectroscopic survey, it is follow-up spectroscopy with JWST. As a to the astronomy community via the SAF. worth briefly considering the question of specific example, high-SNR spectra of More information about the VANDELS legacy science. The immense legacy the Balmer break region of typical z ~ 5 survey, including a full list of Co-Is, can value of the VANDELS survey is compel- galaxies targeted by VANDELS could be be found at the team website1. ling: simply by providing spectra of rela- obtained with NIRSpec in less than one tively faint targets with unprecedentedly hour. high signal-to-noise, VANDELS is guaran- References teed to open up new parameter space Finally, it is also worth noting that the Bradshaw, E. J. et al. 2013, MNRAS, 433, 194 for investigating the physical properties southern position of both the UDS and Brammer, G. B. et al. 2012, ApJS, 200, 13 of high-redshift galaxies. For example, CDFS make them ideal survey fields for Conselice, C. J. 2014, ARA&A, 52, 291 VANDELS will fundamentally improve our sub-millimetre and millimetre wavelength Daddi, E. et al. 2009, ApJL, 695, L176 knowledge of the statistics of Ly- emis- follow-up observations with the Atacama de Barros, A. L. F. et al. 2014, A&A, 563, 81 α Dekel, A. et al. 2009, 457, 451 sion in star-forming galaxies approaching Large Millimeter/submillimeter Array Fabian, A. C. 2012, ARA&A, 50, 455 the reionisation epoch (see Pentericci et (ALMA). One of the key scientific ques- Fontana, A. et al. 2014, A&A, 570, 11 al., 2014) and expedite the identification tions that VANDELS will help to address Garilli, B. et al. 2012, PASP, 124, 1232 of the progenitors of compact galaxies is the evolution of star formation and González, V. et al. 2014, ApJ, 781, 34 Grogin, N. A. et al. 2011, ApJS, 197, 35 amongst star-forming galaxies at z ≥ 2.5. metallicity in galaxies at z ≥ 2. However, Guzzo, L. et al. 2014, A&A, 566, 108 Moreover, additional science will be facili- in order to derive a complete picture it will Le Fèvre, O. et al. 2005, A&A, 439, 845 tated by the samples of rarer bright sys- be necessary to obtain dust mass and Le Fèvre, O. et al. 2015, A&A, 576, 79 tems, such as the Herschel detected gal- star formation rate measurements at long Lilly, S. et al. 2007, ApJS, 172, 70 Mannucci, F. et al. 2010, MNRAS, 408, 211 axies and AGN, targeted by VANDELS. wavelengths, which can now be provided Madau, P. & Dickinson, M. 2014, ARA&A, 52, 415 For these systems, the deep VANDELS by short, targeted, continuum observa- Noeske, K. G. et al. 2007, ApJL, 660, L47 spectroscopy will make it possible to tions with ALMA. Pentericci, L. et al. 2014, ApJ, 793, 113 assess their physical conditions (for exam- Rogers, A. B. et al. 2014, MNRAS, 440, 3714 Shapley, A. E. et al. 2003, ApJ, 588, 65 ple, metallicities, ionising fluxes and out- Somerville, R. S. & Davé, R. 2015, ARA&A, 53, 51 flow signatures) and compare them with Timeline Steidel, C. C. et al. 2016, ApJ, 826, 159 those of less active systems at the same Williams, R. J. et al. 2009, ApJ, 691, 1879 redshifts. The VANDELS survey has just finished its second of three observing seasons and, Links In terms of future follow-up observations, weather depending, is scheduled to be there is an excellent synergy between completed in January 2018. All of the raw 1 VANDELS team website: http://vandels.inaf.it VANDELS and the expected launch date data are immediately available for down-

Part of the Chandra Deep Field South (10.1 × 10.5 arcminutes) imaged by the Wide Field Imager on the MPG/ESO 2.2-metre telescope shown in a B-, V- and R-band composite. See Release eso0302 for further details.

The Messenger 167 – March 2017 35 Astronomical News Astronomical ) atacamaphoto.com Aerial image of the Paranal Observatory shortly before sunset. The VISTA peak is to the left (north- east) and the Residencia and support buildings to the south-east. See ESO Picture of the Week

ESO/G. Hüdepohl ( potw1650a for details.

36 The Messenger 167 – March 2017 Astronomical News DOI: doi.org/10.18727/0722-6691/5007

Report on the 2017 ESO Calibration Workshop: The Second-Generation VLT Instruments and Friends

held at ESO Vitacura, Santiago, Chile, 16–19 January 2017

Alain Smette1 Florian Kerber1 Andreas Kaufer1

1 ESO

The participants at the 2017 ESO Cali- bration Workshop shared their experi- ences and the challenges encountered in calibrating VLT second-generation instruments and the upgraded first- generation instruments, and discussed improvements in the characterisation of the atmosphere and data reduction. A small group of ESO participants held a follow-up retreat and identified possible game changers in the future operations of the La Silla Paranal Observatory: feedback on the proposals is encouraged. VLT Imager and Spectrometer for mid- Figure 1. The attendees at the 2017 Calibration Work- InfraRed (VISIR). In the near future, it shop photographed in the garden of ESO Vitacura. Introduction will evolve further with the completion of the upgrade of the CRyogenic InfraRed – the progress made in characterising Calibration is a critical component in the Echelle Spectrometer (CRIRES) to the properties of the atmosphere that conversion of raw data to material ready CRIRES+, the arrival of the Echelle SPec- allow science operations to make the for scientific analysis. Consequently, a trograph for Rocky Exoplanet and Stable best use of current conditions; complete, consistent calibration plan for Spectroscopic Observations (ESPRESSO) – progress made in data reduction and each dataset fulfilling quality control crite- and the adaptive-optics-assisted instru- pipeline tools. ria was recognised as a cornerstone of ment modes of MUSE and the High Acu- the operation of the Very Large Telescope ity Wide-fieldK -band Imager (HAWK-I). The ESO office in Vitacura was chosen (VLT). In 2007, ESO organised its first In addition, other instruments are in plan: as the venue for the workshop to foster Calibration Workshop (Kaufer & Kerber, SOn of X-Shooter (SOXS) and the Near collaboration between the major ground- 2007) in order to: (a) foster the sharing InfraRed Planet Searcher (NIRPS) at based observatories in Chile. The sunny of information, experience and tech- La Silla; the Enhanced Resolution Imaging weather also allowed the participants to niques between observers, instrument Spectrograph (ERIS) and the Multi Object enjoy lunches and the conference dinner developers and the instrument operation Optical and Near-infrared Spectrograph in the pleasant gardens; see Figure 1. teams; (b) review the actual precision (MOONS) at the VLT; and the 4-metre and limitations of the applied instrument Multi-Object Spectroscopic Telescope calibration plans; and (c) collect the cur- (4MOST) at the Visible and Infrared Sur- The workshop rent and future requirements of the ESO vey Telescope for Astronomy (VISTA). For users. The first Calibration Workshop many of these instruments, the increase The participants — from ESO Headquar- focused on calibration issues affecting in complexity requires challenging cali- ters in Garching and from the Chile sites, the first generation of VLT instruments. bration to achieve optimum performance. from various institutes in Europe, from Gemini Observatory, Las Campanas Ten years later, ESO instrumentation has The 2017 ESO Calibration Workshop Observatory, the Large Synoptic Survey changed considerably following the brought together astronomers and Telescope (LSST) project, US National arrival of second-generation instruments instrument scientists from various fields Institute of Standards and Technology — the K-band Multi-Object Spectrograph of expertise to share their experience, (NIST), the Pontificia Universidad Catolica (KMOS), the Multi Unit Spectroscopic engage in open discussions, challenge de Chile (PUC), the Center for Astronomy Explorer (MUSE), the Spectro-Polarimetric current limitations and try to develop in Harvard, USA, and the Space Telescope High-contrast Exoplanet REsearch creative concepts for better calibration Science Institute (STScI) in Baltimore, instrument (SPHERE) and the X-shooter in the future. The workshop covered: USA — listened to presentations grouped spectrograph — and the completion of – all aspects of calibration that are rele- in sessions organised around a central major upgrades of first-generation ones, vant to the user community or to sci- theme. Most of the sessions included: such as the High Accuracy Radial veloc- ence operations at ESO’s Paranal (VLT) (i) a talk describing an ESO instrument, its ity Planet Searcher (HARPS) and the and La Silla sites; calibration plan and issues affecting the

The Messenger 167 – March 2017 37 Astronomical News Smette A. et al., Report on the “2017 ESO Calibration Workshop”

quality of the data; (ii) an invited talk, or cute novel and innovative self-contained sure time calculator (ETC) callable by a several, on the specific theme of the ses- calibration methods and concepts. A user script, which can also be used to sion; and (iii) contributed talks on various specific session was organised to pre- systematically compare observations calibration or data reduction aspects. sent their content and merit to all partici- with expectations and to analyse hard- Ample time was left after each presenta- pants at the workshop. These calibration ware problems. Furthermore, how tion, and at the end of each session, for proposals will then be executed during could an ETC be used for calibration lively discussion. pre-allocated time in due course. — potentially reducing the number and frequency of on-sky calibrations — The themes of the various sessions were All the presentations, recordings and and how best to follow up on this focused: on calibration of adaptive- question-and-answer sessions will soon approach when comparing the model optics-fed instruments (SPHERE); infrared be available on Zenodo1 or through the with reality? spectroscopy and metrology; high- workshop webpage2. 4. Presentations by Miwa Goto on infra- accuracy wavelength calibration (such as red spectroscopy and Florian Kerber for HARPS, ESPRESSO, and the Giant on the Low Humidity ATmospheric Magellan Telescope [GMT] Consortium The retreat PROfiling radiometer (LHATPRO: Large Earth Finder [G-CLEF]); reference Kerber et al., 2012) indicated that the data (molecular line parameters and After the workshop, a small group of ESO VLT could “fly” when certain conditions atomic lines used for wavelength calibra- participants met at Paranal for a retreat. occur: the amount of precipitable tion); lessons learned from past instru- They identified the following potentially water vapour above Paranal can occa- ments regarding polarimetry; calibrations game-changing topics or actions for the sionally be the same as on a site at for integral field units and sky background operation of the La Silla Paranal Observa- 5000 metres (Kerber et al., 2014)! On reduction strategies in multi-fibre spectro- tory, which were then ordered on a 2D the other hand, the number of pro- graphs; photometry; astrometry; the graph of “scale of impact” vs “likelihood grammes requesting the best seeing Earth’s atmosphere; wide-field surveys, of execution”: conditions is small. If the opportunities as obtained by VISTA’s infrared camera 1. The integration of the high-accuracy are rare, how could the Observatory VIRCAM or the future LSST; and data astrometric and photometric data, best make use of them? ESO should reduction. obtained by Gaia, LSST and surveys promote programmes whose science like the VISTA Hemisphere Survey can only be carried out under excellent The concluding remarks by Susanne (VHS), into ESO operations was recog- conditions. The Call for Proposals for Ramsay (ESO) crystallised various nised by all as the most likely to hap- Period 100 will already mention this themes which often appeared in the vari- pen with the largest impact. Aspects concept, which could be reinforced in ous presentations. For example, is cali- that will be impacted range from the future calls once the implications are bration a tool to fix hardware issues: calibration of the telescope adaptors, better evaluated. can that step be avoided by improving the internal astrometric calibration of 5. Should the calibration strategy be instrument design? Can we rely on physi- instruments like KMOS, to data reduc- better matched to the requested sci- cal instrument models instead? However, tion, on the basis that most fields will ence? At one extreme, we could imag- since everything changes, one must be have a sufficiently high density of stars ine that users provide not only their always attentive and constantly assess for accurate astrometric and photo- science Observing Blocks, but also all the quality of calibrations and their valid- metric calibrations. their Calibration Blocks. The content ity period (semper vigilo): calibration plans 2. Another potentially high-impact topic of such Calibration Blocks would also are living things. But this task should not is how to better characterise the state be based on an ETC to ensure that keep us from being more ambitious, for of the atmosphere and, based on that, the quality of the science data is not example in attempting to reduce the time how to forecast relevant atmospheric degraded, for example due to insuffi- spent on sky-subtraction in the near parameters, along with which data cient signal-to-noise ratio in the flat infrared. Interaction with users is also a should be used for optimal processing fields. key input: data that cannot be reduced of adaptive optics data reduction and 6. Instrument Operations Teams ensure do not return any science! Finally, ESO analysis? An accurate atmospheric that instruments provide the best should prepare now and respond to the profile is also required for optimal cor- science and calibration data. They challenges to be presented by LSST and rection of telluric absorption lines by should, however, be encouraged to the European Space Agency (ESA) Gaia tools such as Molecfit (Smette et al., contact expert users in the community satellite, and for the new instrumentation 2015; Kausch et al., 2015). What will be to promote collaboration with ESO on the 40-metre-class Extremely Large the impact of high-accuracy forecasts and disseminate the knowledge to the Telescope. (in particular, of the turbulence includ- wider community, or to identify specific ing the seeing) on observations within problems with an instrument. An innovative feature of the meeting was a time frame of hours to days? 7. Does the ELT have specific calibration that technical time on the VLT (and on the 3. Physical modelling of the instrument requirements which can only be ESO 3.6-metre) was pre-allocated in behaviour was best illustrated by the addressed by specific VLT observa- preparation for the calibration workshop. talk by Robert Lupton on LSST. Ideas tions? The next few years should be This observing time will be used to exe- that were identified included an expo- used to first identify these needs and

38 The Messenger 167 – March 2017 Astronomical News

then define and conduct the relevant The participants in the retreat compiled operations were identified and need to be observations. and agreed on a list of action items to brought to fruition. We encourage every- 8. New calibration sources such as further explore these different topics and one interested in the subject to further Laser Frequency Combs or stable transform them into specific improve- explore these topics with us through the Fabry-Pérot calibration units will soon ments for their integration into ESO oper- email account [email protected]. become operational at ESO: what is ations. These action items and the corre- their potential for other VLT instru- sponding deadlines will be pursued in ments? Problems with high-purity order to ensure progress towards a timely References Thorium-Argon hollow-cathode lamps implementation. Kaufer, A. & Kerber, F. (eds.) 2007, Proc. ESO following recent stricter environmental Instrument Calibration Workshop, ESO Astro regulations could be dealt with by a physics Symposia, Springer bulk order in collaboration with other Conclusions Kausch, W. et al. 2015, A&A, 576, 78 observatories. Kerber, F. et al. 2012, The Messenger, 148, 9 Kerber, F. et al. 2014, The Messenger, 155, 17 9. ESO should take a more active role in According to the feedback received, the Smette, A. et al. 2015, A&A, 576, 77 defining the needs for laboratory data. 2017 ESO Calibration Workshop Archival data may play a crucial role succeeded in its aim of encouraging dis- to improve molecular line parameters cussion of calibration issues, not only for Links which are required for accurate, syn- ESO instruments but also at other ground- 1 Zenodo: http://www.zenodo.org thetic telluric line correction in tools based observatories. Seeds of potential 2 Conference web page: http://www.eso.org/sci/ such as Molecfit. game changers in improving ESO future meetings/2017/calibration2017.html

DOI: doi.org/10.18727/0722-6691/5008 Highlights from the CERN/ESO/NordForsk Gender in Physics Day

held at CERN, Geneva, Switzerland, 27 January 2017

Francesca Primas1 solid networks. The event was very well the GENERA activities very closely. The Geneviève Guinot2 attended and was declared a success. first meeting of the project was held at Lotta Strandberg3 The main highlights of the meeting are ESO’s Headquarters in June 2015. The reported. final goal of GENERA is very ambitious, i.e., to propose and create organisational 1 ESO structures allowing physics research in 2 CERN, European Organization for GENERA and its objectives Europe to benefit from a more gender- Nuclear Research, Geneva, Switzerland balanced research community. 3 NordForsk, Oslo, Sweden The Gender Equality Network in the European Research Area (GENERA) is a Within the GENERA network, one Horizon 2020 project that focuses on special initiative that looks in more detail In their role as observers on the EU evaluating, monitoring and improving at national gender equality plans and Gender Equality Network in the existing or new gender equality plans of at the existence of innovative activities European Research Area (GENERA) research organisations in the field of that help with the gender balance, is project, funded under the Horizon 2020 physics. The GENERA Consortium the organisation of national Gender in framework, CERN, ESO and NordForsk includes 13 beneficiary partners, either Physics Day (GiPD) events. Each of the joined forces and organised a Gender Research Performing Organisations 13 beneficiary partners is expected to in Physics Day at the CERN Globe of (RPOs) or Research Funding Organisa- organise one such event in their own Science and Innovation. The one-day tions (RFOs) scattered across Europe, country. Each event follows common conference aimed to examine innovative and a number of associate partners organisational guidelines that consist of activities promoting gender equality, and observers. Among the latter, CERN collecting a general overview on the and to discuss gender-oriented policies (the European Organization for Nuclear national situation (both in terms of gender and best practice in the European Research), NordForsk (an organisation statistics and initiatives) and offering topi- Research Area (with special emphasis that facilitates and provides funding cal workshops in the areas most relevant on intergovernmental organisations), for Nordic research cooperation and to that country. as well as the importance of building research infrastructure) and ESO, follow

The Messenger 167 – March 2017 39 Astronomical News Primas F. et al., Highlights from the CERN/ESO/NordForsk “Gender in Physics Day”

The CERN/ESO/NordForsk GiPD

In this spirit, CERN, NordForsk and ESO NordForsk decided to organise a Gender in Physics Day, bringing in the perspective of intergovernmental organisations and the challenges that such international research infrastructures and funding agencies face. All eight EIROforum organisations were invited to join the event. The focus of the day was on the recruitment, reten- tion and career development of female professionals in the field of science, engineering and technology (SET).

The event was meant to be an opportunity to discuss with the academic partners within GENERA the issue of a sustainable scientific or engineering career after Mas- ters, PhD or Postdoctoral employment. All the international research organisations were asked ahead of the meeting to share their gender disaggregated data, as well as measures implemented in their infrastructure, with a critical view on their effectiveness. NordForsk has been fund- ment and the Compact Muon Solenoid Figure 1. The discussion forum on gender statistics ing efforts on the issue of gender balance [CMS] experiment, both at CERN). and equality plans among the EIROforum organisations. From left to right: Ms Ersilia Vaudo (ESA, Head for years and the focus on the field of of Policy Office); Ms Heidi Schmidt (ESO, Head of physics was meant to serve as a case Human Resources); Mr. James Purvis (CERN, Head study for other fields. NordForsk therefore Highlights from the plenary sessions of Talent Acquisition); Mr. Thierry Baudoin (ESRF, brought insight into the situation in the Head of Human Resources). Nordic countries: from how they support The day opened with welcome speeches collaborations with the large infrastruc- by the CERN and ESO Directors General turned out to be rather similar, confirming tures in Europe to what is their gender (Fabiola Giannotti and Tim de Zeeuw, that all four organisations are facing simi- (im)balance in physics. respectively) and by the NordForsk lar challenges, especially as regards Senior Adviser (Lotta Strandberg), wish- hiring and retaining female scientists and This GiPD also offered an opportunity to ing all participants a productive meeting promoting them to the top levels. In the reflect on how gender equality, and more and noting their important exchanges field of engineering, where from the start generally diversity, can be embedded in on best practice and future collaborations. the pool of female candidates is already international collaborations or consortia, significantly smaller, numbers appear to to look at the situation of women in phys- After an introduction and progress report be even more challenging. ics in developing countries, and to listen on GENERA by its Programme Coordi to the expectations of the younger gener- nator, the morning was divided into three The second session was dedicated to ation. main sessions: Gender Equality Plans the Nordic countries. NordForsk was the and Numbers in international RPOs; main host of this part of the programme The programme alternated panel discus- Efforts in Gender Equality and Results in that included detailed overviews of the sions, talks, interactive sessions and the Nordic Countries; and Other Per- gender (im)balance in physics in Denmark, workshops and aimed at targeting a var- spectives. Norway and Sweden. In terms of gender ied audience, ranging from junior and equality, the Nordic countries have rather senior researchers to management-level The first session focused on a direct paved the way over the past several personnel, policy makers and diversity comparison of gender statistics among years, with dedicated legislation, special officers. The event was attended by about some of the EIROforum institutes. Num- hiring/funding programmes and the set- 100 people. All eight EIROforum organi- bers were collected and assembled ting of quotas (for example, on executive sations were represented at the venue, beforehand so that the session could be boards). While these measures have as well as four Nordic countries (Den- structured as a discussion forum, with certainly had a positive impact in some mark, Finland, Norway and Sweden) and representatives of the European Space areas and for some specific positions, members of the largest projects and sci- Agency (ESA), the European Synchrotron all three presentations showed that, even entific collaborations in the current phys- Radiation Facility (ESRF), ESO and CERN if gender equality seems to have been ics world (for example, the ATLAS experi- on stage. Not surprisingly, numbers achieved at college/Masters student

40 The Messenger 167 – March 2017 levels, there remains a significant and Participants then split into four parallel about the lack of transparency in hiring increasing gap as the female researchers workshops: I. How to make a network; processes (even at postdoctoral levels), progress into their academic careers, II. Promoting gender equality pro- and the lack of role models or the exist- with a persistent lack of senior female grammes (GEPs) in international consor- ence of the wrong role models, especially professors, similar to other countries (the tia; III. Expectations from early career in terms of balancing work and private so-called “Nordic Paradox”). scientists on GEPs; and IV. Gender life. Finally, Workshop#4 dealt with how equality initiatives aimed at the general the physics research field is presented The third session was a collection of public (i.e., how to change the image of to the general public. CERN presented different perspectives: from how to imple- physics). A designated Chair moderated two of its initiatives: one that targets an ment gender equality in large scientific each discussion and collected feedback. increase in diversity in CERN’s public collaborations and projects (for example, All four workshops were well attended face via a variety of actions and public large high energy physics teams) to the and discussion was lively and productive. events; the other, gender inclusive teach- situation in astronomy (noting the efforts ing in the CERN High School teacher the International Astronomical Union is The day ended with brief reports from the programme. One of the main outcomes making in this respect) and in the field of workshop chairs, highlighting the main here was about attracting and engaging biology (with a detailed report from the topics of discussion and conclusions that young pupils in science, especially girls, EIROforum EMBL institute); to a look into were reached. Workshop #1 looked into thus breaking through stereotypes and the STEM fields (Science, Technology, two types of networks, the EU GenPORT expanding their knowledge. Engineering and Mathematics) in devel- community project and the String Theory oping countries. The last of those pro- Universe, a Cost Action programme vided an insight into non-western cul- strictly focusing on the gender gap pre- Concluding remarks tures, where the majority of STEM stu- sent in the field of string theory. The audi- dents are actually female. The speaker ence agreed that networks (especially Based on the feedback received, the day presented the results of her investigations social networks) represent important was declared a success, as it covered in Palestine and South Africa, underlining tools to raise awareness but they are not a variety of themes, some of which were the cultural and socio-economic differ- enough and they need a critical mass not often covered in this type of event ences between those countries. The (which depends on goals, expertise and (for example, the challenges faced by equal number of male and female STEM field) in order to be efficient. inter-governmental organisations and the students at Bachelor and PhD level was gender dimension of large scientific col- explained as possibly due to the very dif- Workshop #2 focused on the inclusion laborations). More importantly, the event ferent approach to advanced education. (or lack thereof) of GEPs in international created the pre-requisites, especially While in the western world, the young consortia and organisations. Part of the among international organisations, to fos- generation chooses College and Master discussion was centred on the LHCb ter further exchanges on gender diversity degrees with an eye already on what they collaboration, an international consortium and inclusivity actions. would like to do workwise afterwards, in, (behind one of the CERN Large Hadron for example, Arab countries, college and Collider [LHC] experiments) of more than Masters studies are still considered part 1200 members, involving 71 institutes in Acknowledgements of the basic education, and hence they 16 countries. A constant monitoring of The authors would like to thank all the participants choose what they really like to do, rather gender statistics with no evident improve- for their support and active participation, especially than what is expedient for a career. ment led the collaboration to set up an the EIROforum representatives and the scientific Unfortunately, they know from the start Early Career, Gender and Diversity Office societies in Denmark, Norway and Sweden for per- that the majority will not continue profes- inside LHCb, that now provides advice forming the data collection exercise to a very tight deadline. Special thanks go to the ESO and CERN sionally, as there is a strong social pres- to the team management on equality and directorships and senior management, for endorsing sure to get married and start a family. diversity issues. Raising awareness, and attending the event. Finally, the organisers of improving working conditions and offer- this special Gender in Physics Day would like to ing mentoring were among their final thank the GENERA network and its Programme Coordinator for their support. Highlights from the workshops recommendations. EUROfusion, instead, presented the challenge of implementing After a networking lunch, the afternoon gender equality guidelines and initiatives Links opened with an engaging and provoca- when the employment of staff is handled 1 GENERA: http://genera-project.com tive talk on diversity, touching upon stere- through beneficiaries, with every country 2 NordForsk: https://www.nordforsk.org/ otypes, unconscious bias and work cul- having its own statutes, laws and (equal- 3 EIROforum membership: European Organization ture, followed by some reflections on ity) best practice. for Nuclear Research (CERN), European Molecular gender imbalance in physics in Finland Biology Laboratory (EMBL), European Space Agency (ESA), ESO, European Synchrotron and different proactive measures that Workshop #3 focused on early-career Radiation Facility (ESRF), European Synchrotron could be explored (from mentoring and scientists and touched upon their expec- Radiation Facility (XFEL), EUROfusion and Institut leadership programmes to diversity and tations in terms of gender and work-life Laue-Langevin (ILL) 4 positive discrimination). balance. It was well attended by young GenPORT: http://www.genderportal.eu/ physicists, who expressed concerns

The Messenger 167 – March 2017 41 Astronomical News DOI: doi.org/10.18727/0722-6691/5009

Report on the ESO Python Boot Camp — Pilot Version

held at ESO Vitacura, Santiago, Chile 13–14 October 2016

Bruno Dias1 Julien Milli1 ESO/F. RodriguezESO/F. 1 ESO

The Python programming language is becoming very popular within the astronomical community. Python is a high- level language with multiple applications including database management, handling FITS images and tables, statistical analysis, and more advanced topics. Python is a very powerful tool both for astronomical publications and for observatory operations. Since the best way to learn a new programming Figure 1. (Above) Participants attended the morning Figure 2. (Below) Participants and trainers working language is through practice, we there- classes with their own laptops running Python and together on the proposed projects, and interacting all packages required by the Boot Camp. among different groups to share good ideas. fore organised a two-day hands-on workshop to share expertise among ESO colleagues. We report here the out- come and feedback from this pilot event. ESO/F. RodriguezESO/F.

The first step in launching Python at Vitacura was to hold a weekly informal coffee break centred on Python-related topics, called the ESO PyCoffee1, which began in September 2015. Participants, from beginners to experts, shared their experience of using Python and demon- strated different applications of the language on a large diversity of astronomical problems. After a year with only presentations and discussions, we recognised a need for, and an interest in, more hands- on activities. We therefore started with the pilot version of the ESO Python Boot Camp, which took place on 13 and 14 October 2016. It was meant to be an internal event where the knowledge of more expert Python users could be To mention just a few cases, Berkeley2 and introduced tools useful in processing shared. The main goal was to provide a (the original), the National Aeronautics and astronomical data. In some cases the basic training in Python for astronomers, Space Administration (NASA) Goddard trainers proposed exercises in real time telescope operators and engineers, to Space Flight Center (NASA GSFC3) and using scripts or Jupyter Notebooks. help them in their day-to-day tasks at the the Institute of Astronomy, Geophysics These tools and the knowledge and good Observatory and in their own research. and Atmospheric Sciences of the Univer- practice learned in the morning classes To achieve this goal, we placed particular sity of São Paulo (IAG-USP4), have all were later used to work on specific emphasis on practical examples, so that organised successful events similar to observatory projects during the afternoon trainees could leave the Boot Camp with ours. The Python Boot Camp lasted two sessions. Outlines of these projects are a few scripts installed and running on days, with classes during the mornings presented in the next section. their own computers. and projects in groups during the after- noons (see Figures 1 and 2). Two of the The participants were from many ESO morning classes introduced the specific departments: students, fellows, staff The boot camp concept aspects of Python with respect to other astronomers, telescope operators from languages, presented by the Paranal Science Operations, data analysts from We were not the first to organise a software engineer Claudio Reinero. The ALMA, and Paranal/La Silla engineers Python event focused on astronomy. other classes were astronomy oriented from various teams. Their background in

42 The Messenger 167 – March 2017 0.9 30 Figure 3. Evolution of weather conditions (seeing,

c) 0.8 25 coherence time [τ0], flux and Strehl ratio), plotted in

se 0.7 20 separate panels above, and combined in the large rc

0.6 0 lower panel, as performed in Project 4. τ

(a 15 0.5 0.4 10 0.3 5 Seeing 0.2 0 Project 3 — Extracting data from the 0 0 0 0 0 0 0 0 0 0 0 0 0 0 telescope log :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 03 04 05 06 07 08 09 03 04 05 06 07 08 09 Leader: Daniel Asmus (Fellow) 105 100

ture IR DTTS 80 ) Similarly to Project 2, the participants 104 Vis WFS aper (% 60 used the telescope log files to monitor U/ hl 3 40 tre AD 10 specific parameters of the SPectro

S in 20 polarimetric High-contrast Exoplanet x 102 0 REsearch instrument (SPHERE), the Flu 0 0 0 0 0 0 0 0 0 0 0 0 0 0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 :0 Fibre Large Array Multi-Element Spectro- 03 04 05 06 07 08 09 03 04 05 06 07 08 09 graph (FLAMES), and the VIsible Multi-

ﬂux) 3.0 Object Spectrograph (VIMOS) in order to S 1 8 8 S O 15 uc _3 check the performance of the instru- I_ 26 03 -T WF _A _V

DP ments at startup or the efficiency of RDIF 22 09 47 2.5 01 _I . to -1 -2 S_ GJ-39

ocor acquisition templates. They learned how 19 op HD _n HIP HR55

pr to read a large-volume text file, extract IRDI 12 i_ P2 e 20 2.0 B_

iz information, plot and use shell com- L- L_ (s HD mands in Python. 5344 13 1.5 ZIMPO ZIMPO Strehl d HD Del- an

Project 4 — Plotting the evolution of the 1.0 EU ms

Strehl ratio and atmospheric parame- in ters using SPHERE adaptive optics data 0

/1 0.5 0 τ , Leader: Julien Milli (AO System Scientist)

csec 0.0 ar In this group, the participants were invited in to analyse the adaptive optics (AO) –0.5 0 0 0 0 0 0 0 parameters from a SPHERE observation.

Seeing :0 :0 :0 :0 :0 :0 :0 03 04 05 06 07 08 09 They had to read the parameters from a Night of 2016-06-21 FITS table, save them in a text file, and make quality plots (Figure 3). Advanced Python ranged from complete beginners skills such as manipulating a FITS (Flexi- participants could also correlate the per- to experts. The diversity of backgrounds ble Image Transport System) image and formance with atmospheric parameters proved very fruitful during the interactions header, extracting a spectrum from a 2D by characterising the trends between on the projects. The challenge, on the image, and measuring its full width at half Strehl ratio, star magnitude and coher- other hand, was to hold the attention of maximum (FWHM) were developed. ence time. The conclusion of this project the more expert users without leaving the was that the Strehl ratio is sensitive to a beginners behind. combination of seeing and coherence Project 2 — Tracking the Strehl ratio of time. SINFONI during an Observing Block Group projects Leader: Frédéric Vogt (Fellow) Project 5 — Centre the reference stars Project 1 — Focus curve of UVES on FLAMES This group had to analyse the evolution Leader: Nicolas Haddad (Paranal Instru- of the Strehl ratio during a given Observ- Leader: Jorge Lillo-Box (Fellow) mentation) ing Block (OB) for the Spectrograph for INtegral Field Observations in the Near During acquisition, three or four reference The participants had to analyse the Infrared (SINFONI). They extracted spe- stars must be centred onto a bundle of differences in focus between the two cific information from a complex text file fibres to guarantee good centring of the chips of the Ultraviolet and Visual Echelle containing the log, manipulated strings science targets. This advanced project Spectrograph (UVES) detector and the and time variables, and learned how to aimed at automating this procedure. The focus evolution with time. In this project, make quality plots. participants learned how to make polar

The Messenger 167 – March 2017 43 Astronomical News Dias B. & Milli J., Report on the “ESO Python Boot Camp”

plots, retrieve coordinates by clicking on the plot and apply Bayesian analysis to find the centre of each star; they finally calculated the offset and rotation that 6 should be applied for good centring. Pearson r = –0.78; p = 0

5 Project 6 — Reading and inspecting data using pandas

Leader: Ignacio Toledo (ALMA Data 4

Analyst) s) (m 0 Weather conditions from Paranal are τ 3 available on the ESO webpage5 and anyone can analyse their evolution and correlations. In this project the partici- 2 pants were invited to explore a very large text file with observing conditions of the last 16 years in Paranal using the 1 Python module pandas6 to retrieve and manage information, and the module 0.5 1.01.5 2.0 seaborn7 for graphic inspection of trends. Seeing (ೀ) Figure 4 shows that, for good seeing conditions (< 0.8 arcseconds), there is a something new and useful. More Figure 4. Relation between coherence time (τ0) and range of possible coherence time values, advanced participants contributed differ- Differential Image Motion Monitor (DIMM) seeing during January 2016 at Paranal as analysed in Pro- all suitable for AO corrections on ent points of view on how to solve a given ject 6. SPHERE and NACO for example, in task, which highlighted the flexibility of agreement with Figure 3. Python. for the external community. Nevertheless, this event proved to be very efficient in Most of the participants reached and terms of sharing knowledge that is Feedback and next workshops acknowledged the main goal of this already present among our colleagues. workshop, and can now progress auton- We can recommend this type of initiative After the workshop we sent a feedback omously by self-learning, using web to other research institutes in astronomy. form to the participants to gather their sources and the PyCoffee material. All of If you are struggling with a task, you reactions to this pilot Boot Camp. On a them left the event with Python scripts might have an expert next door willing to scale of 1 to 5 where 1 is maximum, 50 % working on their computers and knowing share his/her knowledge! of the answers gave an overall grade 1 for how to edit and tune them for their own the event and its length at two full days. scientific or operational activities. Among The quality of morning classes received the poll answers some people felt that Acknowledgements grades 2 and 3 in 70 % of the answers. the next run(s) of the Boot Camp should We thank all the teachers and lecturers for their con- The quality of the afternoon projects focus on some specific subjects, rather tribution to this bootcamp. received grades 1 and 2 in 75 % of the than cover a range of topics. answers. These results confirm our expectations that hands-on activities are Finally, 100 % of the respondees agreed Links the best way to go. Based on the com- that we should continue the event. They 1 ESO PyCoffee: www.sc.eso.org/~bdias/pycoffee/. ments and grades we have decided to also said we should keep the mix of peo- Managed by Bruno Dias, Julien Milli, and Callum continue with this style of training project, ple from different ESO and ALMA depart- Bellhouse 2 and we now know where to improve. ments, as long as we remain a small Berkeley Python Boot Camp: https://sites.google. com/site/pythonbootcamp/ event with around 30 participants and 10 3 NASA GSFC Python Boot Camp: https://asd.gsfc. The big challenge of this event was mix- trainers so as to be efficient during the nasa.gov/conferences/pythonbootcamp/2016/ ing participants with different back- hands-on activities and interactions. The 4 IAG-USP Python Boot Camp: http://iagpyboot. grounds and with different levels of majority of respondees agreed with main- wixsite.com/pbc2017 5 Paranal Ambient Query Forms: http://archive.eso. Python knowledge. We proposed that the taining the ESO Python Boot Camp org/cms/eso-data/ambient-conditions/paranal- participants should study the basics of as an internal training workshop for the ambient-query-forms.html Python using the CodeCademy8 platform moment. ESO and ALMA personnel 6 Python Data Analysis Library pandas: and arrive at the Python Boot Camp with change very often, and we depend on http://pandas.pydata.org 7 seaborn statistical data visualisation: at least the same basic level. From this them as trainers. Therefore, we cannot http://seaborn.pydata.org starting point, all participants learned offer an official training session on Python 8 CodeCademy: https://www.codecademy.com

44 The Messenger 167 – March 2017 Astronomical News DOI: doi.org/10.18727/0722-6691/5010

Fellows at ESO

Agnieszka Sybilska cluster-like environment to follow the formation of their substructures. I’ve been interested in learning about the Earth and beyond for as long as I can At ESO I really enjoy the independence remember – at least since I received a and being able to pursue my own children’s cosmos encyclopedia at the research line. Working here has also age of seven. I remember telling everyone given me a unique opportunity to experi- around that a teaspoon of matter from a ence first-hand the forefront of European black hole would weigh 100 million tons astronomical research. Among other — I was fortunate enough to have an things, I got a chance to help as a scien- encouraging family who wanted to listen! tific assistant to the ESO Observing Programmes Committee, which is enor- Having said that, nothing extraordinary mously useful for better understanding happened between then and my high the time allocation process and, hope- school years, other than that I was always fully, being able to write better proposals curious to read and learn more and was in the future (observing or otherwise). I’ve fascinated by stories of planets, distant joked a number of times that when you’re stars and galaxies. I majored in mathe- at ESO you don’t have to travel to be up matics and physics in high school and to date with the latest developments in took a first-year physics laboratory the field — it’s happening right here. While course at the local university, but there an exaggeration of course, the sheer was little to no astronomy in it. There number of conferences/workshops/sym- have been other “loves” in my life and, posia and numerous talks can make your after finishing high school, I first went to head spin — just be careful not to make study English philology and linguistics Agnieszka Sybilska your goal attending all of them! and only when I was in my third year in college, did I decide to start on an There I was a principal investigator of a I’m a keen hiker and it somehow hap- astronomy major as well. Doing the two project devoted to 3D spectroscopic pened that I’ve always picked places to simultaneously was admittedly challeng- imaging of dwarf early-type galaxies, the live abundant with magnificent hiking ing (imagine close to 50 course hours first of its kind for low-mass systems. I trails. This also nicely combines with my a week at three different locations in the worked with Jesus Falcón-Barroso and other hobby — landscape photography. city), but in the end I managed to obtain Glenn van de Ven (Max Planck Institut für I have never abandoned my linguistic two Masters degrees after a total of Astronomie, Germany) and we looked in interests and could say that learning new seven years. particular at the kinematic and dynamical languages when starting a new job was properties of our dwarfs. I got to experi- almost as exciting as the job itself! Thanks What has played a crucial role in my ence first-hand all the steps of project to my astronomy adventures I now speak choosing a career in science, as development: from proposal writing, to almost fluent Spanish and very good opposed to humanities, was definitely preparing observing runs and then carry- German. I’ve always found new chal- an opportunity I got in 2008 to work as ing out observations at the Observatorio lenges exciting and so as my family and a Summer Research Assistant at the del Roque de los Muchachos in La Palma, I move to Poland in a few months, I’m Space Telescope Science Institute (STScI) through to the reduction and analysis of very much looking forward to starting a in Baltimore. Working at the STScI with the data and publishing of the results. job in a new field, working on precise Roeland van der Marel, Alessandra Aloisi astrometry in the context of ESA space and Aaron Grocholski on Hubble Space I moved to Germany a few months after surveillance and tracking activities. Telescope (HST) Wide Field and Plane- finishing my PhD in June 2014, having tary Camera 2 (WFPC2) data of nearby worked on a Space Situational Aware- starburst galaxies was the opportunity ness project for the European Space Annalisa De Cia that allowed me, for the first time, to see Agency (ESA) in between. Two months of world-class science being done. I was an intensive language course in Munich I grew up in a small town in northern Italy, really encouraged by the very positive went by and I was ready to go back to surrounded by the Dolomite mountains attitude towards budding scientists like doing science full-time. My current work and stunning landscapes. As a kid, I myself, which certainly gave me the moti- involves looking at both real and simu- would follow my father’s adventures as vation to continue in the field. The work lated galaxies to better understand the a paraglider pilot, and soon became I did at STScI evolved into a Masters the- importance of the local environment on fascinated by flying machines. My dream sis and certainly served as an excellent their evolution. As for the former, my main back then was to become a fighter-jet springboard to a PhD in astrophysics focus is on stellar populations and star pilot, until I realised I was not really up for which I started in 2009 at the Instituto formation histories of early-types, from the army, nor for wars. But instead I loved de Astrofísica de Canarias in Tenerife, dwarfs to giants. I also look at the evolu- science! At junior-high school I had a Spain. tion of simulated late-type galaxies in a brilliant teacher and great facilities for all

The Messenger 167 – March 2017 45 Astronomical News

sorts of experiments — in electronics, al. 2016, A&A 596, A97) in which, for the optics, chemistry and biology. We would first time, the chemical properties of the make field trips with experts in geology, gas in the Galaxy and in distant galaxies and astronomy too. So I had no doubt were characterised in a unified picture. In that I would enroll in a science high particular, we derived the properties of school later. Soon I learned to have fun the dust and the dust-corrected metallic- with mathematics and physics, and ity in the interstellar medium. became more and more curious about how things work in the Universe. While I have used Very Large Telescope (VLT) observations for my science, I now The University of Bologna was my next have the opportunity to be a night astron- step, where I got both Bachelor and omer on Paranal. As an ESO fellow, I am Masters Degrees in Astronomy and observing with Kueyen (Unit Telescope 2), Astrophysics. As part of my Masters, I driving the UV-Visual Echelle Spectro- spent almost a year at the University of graph (UVES), the Fibre Large Array Multi Calgary, Canada. Back in Italy for my Element Spectrograph (FLAMES) and the Masters thesis, I worked at the Astro- X-shooter spectrograph through their physics Institute (INAF/IASF) on the X-ray diverse science objectives, and learning properties of a low-luminosity active more deeply the science operations at galactic nucleus. While writing my thesis, the Observatory, appreciating the excel- I remember receiving an email regarding lence of these world-leading facilities, a PhD project on even more energetic and participating in ensuring that the and mysterious phenomena, gamma-ray observations run smoothly and efficiently, bursts (GRBs), and their environments. thereby enabling the best science from And in Iceland. Poyekhali!* Annalisa De Cia the collected data. Enjoying a red sunset at the platform, watching the Sun melting Without hesitation, I took up the chal- Factory. In particular, I started to work into the clouds over the Andes (always lenge, and set off on a new adventure. on superluminous supernovae (SLSNe), hoping for a green flash) and the VLT This was in 2008. The Centre for Astro- the most luminous SNe in the Universe, showing its majesty, I feel lucky. None of physics and Cosmology, University of whose origin is a hot and still debated this would have been possible without Iceland, was a small but warm and stimu- field. In the meantime, I became more the many brilliant people who guided or lating astronomy group, which nurtured and more fascinated by small distant inspired me through my journey. I have my scientific growth and also encouraged galaxies, so faint as to elude normal not named any of them here, but I am my independence by supporting visits observations. But we can use bright and grateful to every single one of them. The and extended projects abroad with my distant background sources, such as journey is not over, and I am looking for- external collaborators, such as at the quasars, GRBs, or SLSNe, to probe their ward to what will be next! And I hope that Dark Cosmology Centre (Denmark), ESO gas properties in incomparable detail. science will continue to drive my dreams. in Chile and the University of Leicester In particular, I started to study the metals (UK). My PhD years went by excitingly and dust within these distant systems, between science, aeroplanes and vol- also known as Damped Lyman-α Absorb- Jorge Lillo Box canic eruptions. I am still dreaming about ers (DLAs). The Middle East revealed the tremendous and exotic beauty of Ice- itself as a very intriguing land, with an Astronomy, with its link to philosophy, is landic nature. impressive historical heritage. But unfor- probably one of the oldest sciences in tunately with a complex and painful mili- the history of human beings. Our current During a conference in Nikko, Japan, I tary and political struggle continuing. job is nothing but a technological had learned to appreciate the scientific improvement and knowledge accumu excellence of the Experimental Astro- In time, I developed a strong European lation over the centuries, building on physics Group of the Weizmann Institute feeling, and so I decided to move to a what the Mayas did in Central America, of Science, Israel. So the science call, major astronomical organisation in what the philosophers did in ancient and (literally) favourable winds, took me Europe. I started at ESO as a fellow in Greece, what Hypatia and her disciples south, to the opposite side of Europe. September 2015, and immediately found did in Alexandria, what the Rapa Nui At Weizmann, I was introduced to the myself loving the place, and being involved did in Easter Island, etc. Nothing more, world of supernovae (SNe), and became in observational and scientific activities, nothing less. part of a very active and cutting-edge such as the ”Gas Matters” club, which supernova survey, the Palomar Transient my colleagues and I founded to bring the Becoming an astronomer is a long jour- Garching community together and dis- ney, and many different paths can lead cuss the multi-phase gas inside and out- to this final goal. I am pretty sure each side galaxies. Scientifically, I have just of us has a different story in answer * Russian for ”Let’s go!”, Yuri Gagarin, 1961 published an extensive work (De Cia et to the question “How did I become an

46 The Messenger 167 – March 2017 In the last stages of my PhD, I had another of those “brain please wake up” moments. Suddenly, I found myself applying for postdoc positions and fel- lowships around the world, all of them requiring a “Research Plan”. So, this was an excellent opportunity to be creative, to try breaking the established rules of what we think can and cannot exist in the Universe and to face impossible challenges. From my point of view, this is how we push science to the next level, and so I proposed the TROY project.

ESO gave me a great and unique opportunity not only to develop this project but also to learn, contribute and be part Jorge Lillo Box of one of the greatest astronomical facili- astronomer”. My story is not really a fancy After my degree, I specialised in a hot ties in the world, as part of the Scientific one, it is just my story. Apparently, when topic for my PhD: exoplanets in the con- Operations team of the Very Large Tele- I was a child, with very poor drawing and text of the Kepler mission. My advisor, scope at Paranal. I was assigned as sup- painting skills, I liked to draw stars in all David Barrado, provided me with the port astronomer of the Moon (Kueyen in the school paintings. This passion, how- unique and special opportunity to do my Mapuche language or simply Unit Tele- ever, was hidden in my brain for years, doctorate at the Center for Astrobiology scope 2), instrument fellow of X-shooter just waiting for the appropriate moment in Madrid, and he guided me through and the instrument fellow for the forth- to come out. For a long time I thought this completely new world of astronomi- coming Echelle SPectrograph for Rocky about becoming a mathematician and cal research. From my point of view, this Exoplanet and Stable Spectroscopic teaching maths, because I really liked the is exactly what I needed, just guiding. Observations (ESPRESSO). The new feeling of solving problems and logic During life we are taught many concepts capabilities and opportunities that games. Discovering the mathematics and assumed facts that are, apparently, ESPRESSO will bring for the exoplanet behind the tick-tack-toe grid game, for irrefutable. Freedom of thought is usually community in particular (but also for cos- instance, was one of those moments avoided (or forgotten) during the learning mology and extragalactic studies) make when your brain wakes up after years of process at school and university. How- it a complete challenge from both the being in passive mode and starts asking ever, during my PhD I had the necessary scientific and the technological point of for more and more challenges. This was freedom to start thinking by myself, to view. It is still difficult for me to under- just one year before I started my pure have my own ideas, to start questioning stand that we will be able to measure the physics course at the high school. And what I was taught. So, this was another radial component of the velocity of a star that was really the critical turning point. of those moments, mentioned before, located hundreds of parsecs away with when my brain woke up again and a precision better than the speed of a I had the luck to have an extremely expe- started exploring new ways of thinking, walking turtle. Just amazing! rienced, motivated, encouraging, and looking for new challenges. great physics and chemistry teacher. By I am looking forward to seeing just using chalk and the blackboard, he And this is how I accomplished one of ESPRESSO in operation and the new was able to open our minds, our brains, my dreams. Even though thousands of space- and ground-based facilities and, last but not least, our interest in planets have already been discovered, coming in the near future (CHaracterising answering the question “Why?”. Why do one of them will always be very special to ExOPlanet Satellite [CHEOPS], PLAnetary things happen as they do in nature? me. This is Kepler-91b, my first discov- Transits and Oscillations of stars [PLATO], What are the forces governing our world? ered planet. This hot Jupiter was the first the James Webb Space Telescope Then in the same year I skipped my first planet confirmed to transit a giant star [JWST], etc.), as well as to develop my class at high school to see the 2004 tran- and the closest planet to an evolved host own ambitious scientific projects. All this sit of Venus using binoculars with solar ascending the red giant branch, orbiting is contributing to our understanding of filters attached. So, during the last two at just 2.3 stellar radii around the star the place in which we live, the Universe years of high school, this hidden passion and the only planet known around a giant we inhabit. Just continuing what our for astronomy that had been there since star closer than 0.5 au at that time. A ancestors did years, centuries and mil- I was a child, suddenly came out, and I handful of planets of this kind were dis- lennia ago. Nothing more, nothing less! finally said these words to my parents: covered afterwards and they proved to “Mom, Dad, I want to become an astron- be key to our understanding of the evolu- omer”. tion of planetary systems once the star leaves the main sequence.

The Messenger 167 – March 2017 47 Astronomical News

Personnel Movements

Arrivals (1 January–31 March 2017) Departures (1 January–31 March 2017)

Europe Europe Czepanski, Jasna (DE) Administrative Assistant Bhardwaj, Anupam (IN) Student Flörs, Andreas (DE) Student Cortes, Angela (CL) Instrumentation Engineer François, Mylène (FR) Administrative and Document Lampinen, Mervi Johanna (FI) Head of Information Management Assistant Technology Department George, Elizabeth (US) Detector Engineer Mc Leod, Anna Faye (FR) Student Guglielmetti, Fabrizia (IT) ALMA Pipeline Processing Analyst Rabanus, David (DE) Electronics Engineer Harrison, Christopher (UK) Fellow Turner, Owen James (UK) Student Haug, Marcus (DE) Cryogenic Systems Engineer Lelli, Federico (IT) Fellow Lucchesi, Romain (FR) Student Montesino Pouzols, Federico (ES) Software Engineer Müller, Eric (DE) Instrumentation Engineer Nogueras Lara, Francisco (ES) Student

Chile Chile Aguilar, Max (CL) Hospitality Operations Supervisor Guzman, Lizette (MX) Fellow Carcamo, Carolina (CL) Procurement Officer Cardenas, Mauricio (CL) Telescope Instruments Operator Ciechanowicz, Miroslaw (PL) Senior Electronics Engineer Muñoz, Miguel Patricio (CL) Electronics Technician Muñoz, Ingeborg (CL) Unix-Database Specialist Rojas, Alejandra (CL) Student Santamaría Miranda, Alejandro (ES) Student ESO/S. Fandango ESO/S.

View of the ALMA Operations Site (AOS) from inside the AOS Technical Building. See Picture of the Week potw1642 for more information.

48 The Messenger 167 – March 2017 Annual Index

Annual Index 2016 (Nos. 163–166)

Subject Index VLT/VLTI Second-Generation Instrumentation: The LEGA-C Survey: The Physics of Galaxies 7 Gyr Lessons Learned; Gilmozzi, R.; Pasquini, L.; Ago; van der Wel, A.; Noeske, K.; Bezanson, R.; Russell, A.; 166, 29 Pacifici, C.; Gallazzi, A.; Franx, M.; Muñoz-Mateos, The Organisation Science-Grade Imaging Data for HAWK-I, VIMOS, J.-C.; Bell, E. F.; Brammer, G.; Charlot, S.; and VIRCAM: The ESO–UK Pipeline Chauké, P.; Labbé, I.; Maseda, M. V.; Muzzin, A.; The Signing of the ALMA Trilateral Agreement; Gube, Collaboration; Neeser, M.; Lewis, J.; Madsen, G.; Rix, H.-W.; Sobral, D.; van de Sande, J.; van N.; de Zeeuw, T.; 163, 2 Yoldas, A.; Irwin, M.; Gabasch, A.; Coccato, L.; Dokkum, P. G.; Wild, V.; Wolf, C.; 164, 36 Reaching New Heights in Astronomy — ESO Long García-Dabó, C. E.; Romaniello, M.; Freudling, W.; ALMACAL: Exploiting ALMA Calibrator Scans to Term Perspectives; de Zeeuw, T.; 166, 2 Ballester, P.; 166, 36 Carry Out a Deep and Wide (Sub)millimetre Annual Index 2015; ESO; 163, 60 Stereo-SCIDAR: Instrument and First Commissioning Survey, Free of Cosmic Variance; Oteo, I.; Zwaan, Results; Derie, F.; Wilson, R.; Osborn, J.; M.; Ivison, R.; Smail, I.; Biggs, A.; 164, 41 Dubbeldam, M.; Sarazin, M.; Ridings, R.; Globular Clusters and the Milky Way Connected by Telescopes and Instrumentation Navarrete, J.; Lelouarn, M.; 166, 41 Chemistry; Dias, B.; Saviane, I.; Barbuy, B.; Held, E. V.; Da Costa, G.; Ortolani, S.; Gullieuszik, M.; The Growth of the User Community of the La Silla 165, 19 Paranal Observatory Science Archive; Romaniello, Astronomical Science Connecting the Dots: MUSE Unveils the Destructive M.; Arnaboldi, M.; Da Rocha, C.; De Breuck, C.; Effect of Massive Stars; McLeod, A. F.; Ginsburg, Delmotte, N.; Dobrzycki, A.; Fourniol, N.; New Eyes on the Sun — Solar Science with ALMA; A.; Klaassen, P.; Mottram, J.; Ramsay, S.; Testi, Freudling, W.; Mascetti, L.; Micol, A.; Retzlaff, J.; Wedemeyer, S.; 163, 15 L.; 165, 22 Sterzik, M.; Vera Sequeiros, I.; Vuong De Breuck, The Central Role of FORS1/2 Spectropolarimetric From ATLASGAL to SEDIGISM: Towards a Complete M.; 163, 5 Observations for the Progress of Stellar 3D View of the Dense Galactic Interstellar FORS2 Rotating Flat Field Systematics Fixed — Magnetism Studies; Schöller, M.; Hubrig, S.; Ilyin, Medium; Schuller, F.; Urquhart, J.; Bronfman, L.; Recent Exchange of FORS LADC Prisms I.; Steffen, M.; Briquet, M.; Kholtygin, A. F.; 163, Csengeri, T.; Bontemps, S.; Duarte-Cabral, A.; Improves the Long-known Flat-fielding Problem; 21 Giannetti, A.; Ginsburg, A.; Henning, T.; Immer, K.; Boffin, H.; Moehler, S.; Freudling, W.; 163, 10 The QUEST–La Silla AGN Variability Survey; Cartier, Leurini, S.; Mattern, M.; Menten, K.; Molinari, S.; A Simpler Procedure for Specifying Solar System R.; Lira, P.; Coppi, P.; Sánchez, P.; Arévalo, P.; Muller, E.; Sánchez-Monge, A.; Schisano, E.; Suri, Objects in Phase 2; Carry, B.; Berthier, J.; 163, 12 Bauer, F. E.; Muñoz, R. R.; 163, 26 S.; Testi, L.; Wang, K.; Wyrowski, F.; Zavagno, A.; Adaptive Optics Facility Status Report: When First Towards a Fundamental Astrometric Reference 165, 27 Light Is Produced Rather Than Captured; System behind the Magellanic Clouds: Ultra-deep K-band Imaging of the Hubble Frontier Arsenault, R.; Madec, P.-Y.; Vernet, E.; Spectroscopic Confirmation of New Quasar Fields; Brammer, G. B.; Marchesini, D.; Labbé, I.; Hackenberg, W.; Bonaccini Calia, D.; La Penna, Candidates Selected in the Near-infrared; Ivanov, Spitler, L.; Lange-Vagle, D.; Barker, E. A.; Tanaka, P.; Paufique, J.; Kuntschner, H.; Pirard, J.-F.; V. D.; Cioni, M.-R. L.; Bekki, K.; de Grijs, R.; M.; Fontana, A.; Galametz, A.; Ferré-Mateu, A.; Sarazin, M.; Haguenauer, P.; Hubin, N.; Vera, I.; Emerson, J.; Gibson, B. K.; Kamath, D.; van Loon, Kodama, T.; Lundgren, B.; Martis, N.; Muzzin, A.; 164, 2 J. Th.; Piatti, A. E.; For, B.-Q.; 163, 32 Stefanon, M.; Toft, S.; van der Wel, A.; Vulcani, B.; A Fruitful Collaboration between ESO and the Max The KMOS AGN Survey at High Redshift (KASHz); Whitaker, K. E.; 165, 34 Planck Computing and Data Facility; Fourniol, N.; Harrison, C.; Alexander, D.; Mullaney, J.; Stott, J.; A Deep ALMA Image of the Hubble Ultra Deep Field; Zampieri, S.; Panea, M.; 164, 8 Swinbank, M.; Arumugam, V.; Bauer, F.; Bower, Dunlop, J. S.; 166, 48 Solar Activity-driven Variability of Instrumental Data R.; Bunker, A.; Sharples, R.; 163, 35 First ALMA Detection of a Galaxy Cluster Merger Quality; Martayan, C.; Smette, A.; Hanuschik, R.; A Stellar Census in NGC 6397 with MUSE; Kamann, Shock; Basu, K.; Sommer, M.; Erler, J.; Eckert, D.; van Der Heyden, P.; Mieske, S.; 164, 10 S.; Husser, T.-O.; Wendt, M.; Bacon, R.; Vazza, F.; Magnelli, B.; Bertoldi, F.; Tozzi, P.; 166, Science Verification for the VISIR Upgrade; Asmus, Brinchmann, J.; Dreizler, S.; Emsellem, E.; 53 D.; van den Ancker, M.; Ivanov, V.; Käufl, H.-U.; Krajnović, D.; Monreal-Ibero, A.; Roth, M. M.; Kerber, F.; Leibundgut, B.; Mehner, A.; Momany, Weilbacher, P. M.; Wisotzki, L.; 164, 18 Y.; Pantin, E.; Tristram, K. R. W.; 164, 14 Pulsating Hot Subdwarfs in Omega Centauri; Astronomical News Gender Systematics in Telescope Time Allocation at Randall, S. K.; Calamida, A.; Fontaine, G.; Monelli, ESO; Patat, F.; 165, 2 M.; Bono, G.; Alonso, M. L.; Van Grootel, V.; Light Phenomena over the ESO Observatories I: The Next Generation Transit Survey Becomes Brassard, P.; Chayer, P.; Catelan, M.; Littlefair, S.; Airglow; Christensen, L. L.; Noll, S.; Horálek, P.; Operational at Paranal; West, R. G.; Pollacco, D.; Dhillon, V. S.; Marsh, T. R.; 164, 23 163, 40 Wheatley, P.; Goad, M.; Queloz, D.; Rauer, H.; First Results from the XXL Survey and Associated Light Phenomena over the ESO Observatories II: Watson, C.; Udry, S.; Bannister, N.; Bayliss, D.; Multi-wavelength Programmes; Adami, C.; Pierre, Red Sprites; Horálek, P.; Christensen, L. L.; Bór, Bouchy, F.; Burleigh, M.; Cabrera, J.; Chaushev, M.; Baran, N.; Eckert, D.; Fotopoulou, S.; Giles, P. J.; Setvák, M.; 163, 43 A.; Chazelas, B.; Crausaz, M.; Csizmadia, S.; A.; Koulouridis, E.; Lidman, C.; Lieu, M.; Mantz, A. Report on the ESO–ESA Workshop “Science Eigmüller, P.; Erikson, A.; Genolet, L.; Gillen, E.; B.; Pacaud, F.; Pompei, E.; Smolčić, V.; Ziparo, F.; Operations 2015: Science Data Management”; Grange, A.; Günther, M.; Hodgkin, S.; Kirk, J.; XXL Team; 164, 27 Romaniello, M.; Arviset, C.; Leibundgut, B.; Lambert, G.; Louden, T.; McCormac, J.; Metrailler, Lennon, D.; Sterzik, M.; 163, 46 L.; Neveu, M.; Smith, A.; Thompson, A.; Raddi, R.; Report on “European Radio Interferometry School Walker, S. R.; Jenkins, J.; Jordán, A.; 165, 10 2015”; Laing, R.; Richards, A.; 163, 50 SEPIA — A New Instrument for the Atacama The AstroMundus–ESO Connection; Humphreys, L.; Pathfinder Experiment (APEX) Telescope; Immer, Hussain, G.; Biggs, A.; Lu, H.-Y.; Emsellem, E.; De K.; Belitsky, V.; Olberg, M.; De Breuck, C.; Cia, A.; Lavail, A.; Spyromilio, J.; 163, 51 Conway, J.; Montenegro-Montes, F. M.; Perez- Gert Finger Becomes Emeritus Physicist; de Zeeuw, Beaupuits, J.-P.; Torstensson, K.; Billade, B.; De T.; Lucuix, C.; Péron, M.; 163, 53 Beck, E.; Ermakov, A.; Ferm, S.-E.; Fredrixon, M.; Fellows at ESO; McClure, M.; Milli, J.; Ginsburg, A.; Lapkin, I.; Meledin, D.; Pavolotsky, A.; Strandberg, 163, 54 M.; Sundin, E.; Arumugam, V.; Galametz, M.; Humphreys, E.; Klein, T.; Adema, J.; Barkhof, J.; Personnel Movements; ESO; 163, 57 Baryshev, A.; Boland, W.; Hesper, R.; Klapwijk, T. ESO Studentship Programme 2016/2017; ESO; 163, M.; 165, 13 58

The Messenger 167 – March 2017 49 Annual Index

Light Phenomena over the ESO Observatories III: Report on the ESO/MPA/MPE/Excellence Cluster/ Personnel Movements; ESO; 165, 53 Zodiacal Light; Horálek, P.; Christensen, L. L.; LMU and TUM Munich Joint Conference “Discs in Resolving Planet Formation in the Era of ALMA and Nesvorný, D.; Davies, R.; 164, 45 Galaxies”; Ellis, R.; 165, 39 Extreme AO Report on the joint ESO/NRAO The First NEON School in La Silla; Dennefeld, M.; Report on the ESO Workshop “Active Galactic Conference; Dent, W. R. F.; Hales, A.; Milli, J.; Melo, C.; Selman, F.; 164, 47 Nuclei: what’s in a name?”; Padovani, P.; 165, 44 166, 59 Report on the ESO Data Simulation Workshop; Report on the ESO/OPTICON “Instrumentation Very Large Telescope Adaptive Optics Community Ballester, P.; 164, 50 School on Use and Data Reduction of X-shooter Days Report on the ESO Workshop; Leibundgut, Retirement of Lothar Noethe; Spyromilio, J.; and KMOS”; Ballester, P.; Dennefeld M.; 165, 45 B.; Kasper, M.; Kuntschner, H.; 166, 62 Holzlöhner, R.; 164, 52 Report on the “ALMA Developers’ Workshop”; Laing, Claus Madsen Retires; de Zeeuw, T.; Walsh, J.; 166, Fellows at ESO; Immer, K.; Johnston, E.; Kerzendorf, R.; Mroczkowski, T.; Testi, L.; 165, 47 65 W.; 164, 54 Fellows at ESO; Visser, R.; Watson, L.; Asmus, D.; Retirement of Dietrich Baade; Walsh, J.; 166, 66 Personnel Movements; ESO; 164, 57 165, 49 Fellows at ESO; Jaffé, Y.; Stroe, A.; Xu, S.; 166, 68 ESO Fellowship Programme 2016/2017; ESO; 164, ESO Studentship Programme 2016 — 2nd Call; Personnel Movements; ESO; 166, 71 58 ESO; 165, 52

Author Index Brammer, G. B.; Marchesini, D.; Labbé, I.; Spitler, L.; Dias, B.; Saviane, I.; Barbuy, B.; Held, E. V.; Da Lange-Vagle, D.; Barker, E. A.; Tanaka, M.; Costa, G.; Ortolani, S.; Gullieuszik, M.; Globular Fontana, A.; Galametz, A.; Ferré-Mateu, A.; Clusters and the Milky Way Connected by A Kodama, T.; Lundgren, B.; Martis, N.; Muzzin, A.; Chemistry; 165, 19 Stefanon, M.; Toft, S.; van der Wel, A.; Vulcani, B.; Dunlop, J. S.; A Deep ALMA Image of the Hubble Adami, C.; Pierre, M.; Baran, N.; Eckert, D.; Whitaker, K. E.; Ultra-deep K-band Imaging of the Ultra Deep Field; 166, 48 Fotopoulou, S.; Giles, P. A.; Koulouridis, E.; Hubble Frontier Fields; 165, 34 Lidman, C.; Lieu, M.; Mantz, A. B.; Pacaud, F.; Pompei, E.; Smolčić, V.; Ziparo, F.; XXL Team; E First Results from the XXL Survey and Associated C Multi-wavelength Programmes; 164, 27 Ellis, R.; Report on the ESO/MPA/MPE/Excellence Arsenault, R.; Madec, P.-Y.; Vernet, E.; Hackenberg, Carry, B.; Berthier, J.; A Simpler Procedure for Cluster/LMU and TUM Munich Joint Conference W.; Bonaccini Calia, D.; La Penna, P.; Paufique, J.; Specifying Solar System Objects in Phase 2; 163, “Discs in Galaxies”; 165, 39 Kuntschner, H.; Pirard, J.-F.; Sarazin, M.; 12 Haguenauer, P.; Hubin, N.; Vera, I.; Adaptive Cartier, R.; Lira, P.; Coppi, P.; Sánchez, P.; Arévalo, Optics Facility Status Report: When First Light Is P.; Bauer, F. E.; Muñoz, R. R.; The QUEST– G Produced Rather Than Captured; 164, 2 La Silla AGN Variability Survey; 163, 26 Asmus, D.; van den Ancker, M.; Ivanov, V.; Käufl, Christensen, L. L.; Noll, S.; Horálek, P.; Light Gilmozzi, R.; Pasquini, L.; Russell, A.; VLT/VLTI H.-U.; Kerber, F.; Leibundgut, B.; Mehner, A.; Phenomena over the ESO Observatories I: Second-Generation Instrumentation: Lessons Momany, Y.; Pantin, E.; Tristram, K. R. W.; Science Airglow; 163, 40 Learned; 166, 29 Verification for the VISIR Upgrade; 164, 14 Gube, N.; de Zeeuw, T.; The Signing of the ALMA Trilateral Agreement; 163, 2 D B de Zeeuw, T.; Lucuix, C.; Péron, M.; Gert Finger H Ballester, P.; Report on the ESO Data Simulation Becomes Emeritus Physicist; 163, 53 Workshop; 164, 50 de Zeeuw, T.; Reaching New Heights in Astronomy Harrison, C.; Alexander, D.; Mullaney, J.; Stott, J.; Ballester, P.; Dennefeld M.; Report on the ESO/ — ESO Long Term Perspectives; 166, 2 Swinbank, M.; Arumugam, V.; Bauer, F.; Bower, OPTICON “Instrumentation School on Use and de Zeeuw, T.; Walsh, J.; Claus Madsen Retires; 166, R.; Bunker, A.; Sharples, R.; The KMOS AGN Data Reduction of X-shooter and KMOS”; 165, 45 65 Survey at High Redshift (KASHz); 163, 35 Basu, K.; Sommer, M.; Erler, J.; Eckert, D.; Vazza, F.; Dennefeld, M.; Melo, C.; Selman, F.; The First NEON Horálek, P.; Christensen, L. L.; Bór, J.; Setvák, M.; Magnelli, B.; Bertoldi, F.; Tozzi, P.; First ALMA School in La Silla; 164, 47 Light Phenomena over the ESO Observatories II: Detection of a Galaxy Cluster Merger Shock; 166, Red Sprites; 163, 43 53 Dent, W. R. F.; Hales, A.; Milli, J.; Resolving Planet Formation in the Era of ALMA and Extreme AO Horálek, P.; Christensen, L. L.; Nesvorný, D.; Davies, Boffin, H.; Moehler, S.; Freudling, W.; FORS2 Report on the joint ESO/NRAO Conference; 166, R.; Light Phenomena over the ESO Observatories Rotating Flat Field Systematics Fixed — Recent 59 III: Zodiacal Light; 164, 45 Exchange of FORS LADC Prisms Improves the Humphreys, L.; Hussain, G.; Biggs, A.; Lu, H.-Y.; Long-known Flat-fielding Problem; 163, 10 Derie, F.; Wilson, R.; Osborn, J.; Dubbeldam, M.; Sarazin, M.; Ridings, R.; Navarrete, J.; Lelouarn, Emsellem, E.; De Cia, A.; Lavail, A.; Spyromilio, J.; M.; Stereo-SCIDAR: Instrument and First The AstroMundus–ESO Connection; 163, 51 Commissioning Results; 166, 41

50 The Messenger 167 – March 2017 I M S

Immer, K.; Johnston, E.; Kerzendorf, W.; Fellows at Martayan, C.; Smette, A.; Hanuschik, R.; van Der Schöller, M.; Hubrig, S.; Ilyin, I.; Steffen, M.; Briquet, ESO; 164, 54 Heyden, P.; Mieske, S.; Solar Activity-driven M.; Kholtygin, A. F.; The Central Role of FORS1/2 Immer, K.; Belitsky, V.; Olberg, M.; De Breuck, C.; Variability of Instrumental Data Quality; 164, 10 Spectropolarimetric Observations for the Conway, J.; Montenegro-Montes, F. M.; Perez- McClure, M.; Milli, J.; Ginsburg, A.; Fellows at ESO; Progress of Stellar Magnetism Studies; 163, 21 Beaupuits, J.-P.; Torstensson, K.; Billade, B.; De 163, 54 Schuller, F.; Urquhart, J.; Bronfman, L.; Csengeri, T.; Beck, E.; Ermakov, A.; Ferm, S.-E.; Fredrixon, M.; McLeod, A. F.; Ginsburg, A.; Klaassen, P.; Mottram, Bontemps, S.; Duarte-Cabral, A.; Giannetti, A.; Lapkin, I.; Meledin, D.; Pavolotsky, A.; Strandberg, J.; Ramsay, S.; Testi, L.; Connecting the Dots: Ginsburg, A.; Henning, T.; Immer, K.; Leurini, S.; M.; Sundin, E.; Arumugam, V.; Galametz, M.; MUSE Unveils the Destructive Effect of Massive Mattern, M.; Menten, K.; Molinari, S.; Muller, E.; Humphreys, E.; Klein, T.; Adema, J.; Barkhof, J.; Stars; 165, 22 Sánchez-Monge, A.; Schisano, E.; Suri, S.; Testi, Baryshev, A.; Boland, W.; Hesper, R.; Klapwijk, T. L.; Wang, K.; Wyrowski, F.; Zavagno, A.; From M.; SEPIA — A New Instrument for the Atacama ATLASGAL to SEDIGISM: Towards a Complete 3D Pathfinder Experiment (APEX) Telescope; 165, 13 N View of the Dense Galactic Interstellar Medium; Ivanov, V. D.; Cioni, M.-R. L.; Bekki, K.; de Grijs, R.; 165, 27 Emerson, J.; Gibson, B. K.; Kamath, D.; van Loon, Neeser, M.; Lewis, J.; Madsen, G.; Yoldas, A.; Irwin, Spyromilio, J.; Holzlöhner, R.; Retirement of Lothar J. Th.; Piatti, A. E.; For, B.-Q.; Towards a M.; Gabasch, A.; Coccato, L.; García-Dabó, C. E.; Noethe; 164, 52 Fundamental Astrometric Reference System Romaniello, M.; Freudling, W.; Ballester, P.; behind the Magellanic Clouds: Spectroscopic Science-Grade Imaging Data for HAWK-I, VIMOS, Confirmation of New Quasar Candidates Selected and VIRCAM: The ESO–UK Pipeline V in the Near-infrared; 163, 32 Collaboration; 166, 36 van der Wel, A.; Noeske, K.; Bezanson, R.; Pacifici, C.; Gallazzi, A.; Franx, M.; Muñoz-Mateos, J.-C.; J O Bell, E. F.; Brammer, G.; Charlot, S.; Chauké, P.; Labbé, I.; Maseda, M. V.; Muzzin, A.; Rix, H.-W.; Jaffé, Y.; Stroe, A.; Xu, S.; Fellows at ESO; 166, 68 Oteo, I.; Zwaan, M.; Ivison, R.; Smail, I.; Biggs, A.; Sobral, D.; van de Sande, J.; van Dokkum, P. G.; ALMACAL: Exploiting ALMA Calibrator Scans to Wild, V.; Wolf, C.; The LEGA-C Survey: The Carry Out a Deep and Wide (Sub)millimetre Physics of Galaxies 7 Gyr Ago; 164, 36 K Survey, Free of Cosmic Variance; 164, 41 Visser, R.; Watson, L.; Asmus, D.; Fellows at ESO; 165, 49 Kamann, S.; Husser, T.-O.; Wendt, M.; Bacon, R.; Brinchmann, J.; Dreizler, S.; Emsellem, E.; P Krajnović, D.; Monreal-Ibero, A.; Roth, M. M.; W Weilbacher, P. M.; Wisotzki, L.; A Stellar Census in Padovani, P.; Report on the ESO Workshop “Active NGC 6397 with MUSE; 164, 18 Galactic Nuclei: what’s in a name?”; 165, 44 Walsh, J.; Retirement of Dietrich Baade; 166, 66 Patat, F.; Gender Systematics in Telescope Time Wedemeyer, S.; New Eyes on the Sun — Solar Allocation at ESO; 165, 2 Science with ALMA; 163, 15 L West, R. G.; Pollacco, D.; Wheatley, P.; Goad, M.; Queloz, D.; Rauer, H.; Watson, C.; Udry, S.; Laing, R.; Richards, A.; Report on “European Radio R Bannister, N.; Bayliss, D.; Bouchy, F.; Burleigh, M.; Interferometry School 2015”; 163, 50 Cabrera, J.; Chaushev, A.; Chazelas, B.; Crausaz, Randall, S. K.; Calamida, A.; Fontaine, G.; Monelli, M.; Csizmadia, S.; Eigmüller, P.; Erikson, A.; Laing, R.; Mroczkowski, T.; Testi, L.; Report on the M.; Bono, G.; Alonso, M. L.; Van Grootel, V.; Genolet, L.; Gillen, E.; Grange, A.; Günther, M.; “ALMA Developers’ Workshop”; 165, 47 Brassard, P.; Chayer, P.; Catelan, M.; Littlefair, S.; Hodgkin, S.; Kirk, J.; Lambert, G.; Louden, T.; Leibundgut, B.; Kasper, M.; Kuntschner, H.; Very Dhillon, V. S.; Marsh, T. R.; Pulsating Hot McCormac, J.; Metrailler, L.; Neveu, M.; Smith, A.; Large Telescope Adaptive Optics Community Subdwarfs in Omega Centauri; 164, 23 Thompson, A.; Raddi, R.; Walker, S. R.; Jenkins, Days Report on the ESO Workshop; 166, 62 Romaniello, M.; Arnaboldi, M.; Da Rocha, C.; J.; Jordán, A.; The Next Generation Transit Survey De Breuck, C.; Delmotte, N.; Dobrzycki, A.; Becomes Operational at Paranal; 165, 10 Fourniol, N.; Freudling, W.; Mascetti, L.; Micol, A.; Retzlaff, J.; Sterzik, M.; Vera Sequeiros, I.; Vuong De Breuck, M.; The Growth of the User Community of the La Silla Paranal Observatory Science Archive; 163, 5 Romaniello, M.; Arviset, C.; Leibundgut, B.; Lennon, D.; Sterzik, M.; Report on the ESO–ESA Workshop “Science Operations 2015: Science Data Management”; 163, 46

The Messenger 167 – March 2017 51 ESO, the European Southern Observa- Contents tory, is the foremost intergovernmental astronomy organisation in Europe. It Telescopes and Instrumentation is supported by 16 countries: Austria, Stoehr F. et al. — The ALMA Science Archive 2 Belgium, Brazil, the Czech Republic, Humphreys L. et al. — ALMA Band 5 Science Verification 7 Denmark, France, Finland, Germany, De Breuck C. et al. — Report on the ESO Workshop Italy, the Netherlands, Poland, Portugal, “Getting Ready for ALMA Band 5 — Synergy with APEX/SEPIA” 11 Spain, Sweden, Switzerland and the United Kingdom. ESO’s programme is Astronomical Science focused on the design, construction Popescu M. et al. — Minor Planet Science with the VISTA Hemisphere Survey 16 and operation of powerful ground- Kervella P. et al. — The Nearby Evolved Star L2 Puppis as a Portrait of the based observing facilities. ESO oper- Future Solar System 20 ates three observatories in Chile: at Spyromilio J. et al. — Supernova 1987A at 30 26 La Silla, at Paranal, site of the Very McLure R. et al. — VANDELS: Exploring the Physics of High-redshift Large Telescope, and at Llano de Galaxy Evolution 31 Chajnantor. ESO is the European partner in the Atacama Large Millimeter/sub- Astronomical News millimeter Array (ALMA). Currently ESO Smette A. et al. — Report on the “2017 ESO Calibration Workshop: is engaged in the construction of the The Second-Generation VLT Instruments and Friends” 37 Extremely Large Telescope. Primas F. et al. — Highlights from the CERN/ESO/NordForsk “Gender in Physics Day” 39 The Messenger is published, in hard- Dias B. & Milli J. — Report on the “ESO Python Boot Camp — Pilot Version” 42 copy and electronic form, four times Fellows at ESO — Sybilska A., De Cia A., Lillo Box J. 45 a year: in March, June, September and Personnel Movements 48 December. ESO produces and distrib- utes a wide variety of media connected Annual Index 2016 (Nos. 163–166) 49 to its activities. For further information, including postal subscription to The Messenger, contact the ESO education and Public Outreach Department at:

ESO Headquarters Karl-Schwarzschild-Straße 2 Front cover: An album of images and spectra of SN 1987A tracing the evolution of the supernova observed with ESO facilities: The Messenger 85748 Garching bei München, Germany 1. The Large Magellanic Cloud (LMC) before explosion of Phone +498932006-0 SN 1987A; ESO 1-metre Schmidt optical image. 1 [email protected] 2. SN 1987A close to its peak brightness; ESO Schmidt image 2 in optical. The Messenger: 3 3. Optical spectral evolution of SN 1987A over first 110 days; 4 Editor: Jeremy R. Walsh; sequence with Bochum telescope (from Hanuschik & Thimm, 6 Design, Production: Jutta Boxheimer; 1990, A&A, 231, 77). 5 Layout, Typesetting: Mafalda Martins; 4. Light echoes around SN 1987A; NTT Hα image from 1992. 7 Graphics: Ed Janssen. 5. ISAAC broad slit spectrum centred on He I 1.083 μm line 9 www.eso.org/messenger/ from 1999. 8 6. UVES spectrum centred on Hα taken in 1999. Printed by G. Peschke Druckerei GmbH 7. Early NTT [N II] 6583 Å image of SN 1987A from 1991. Taxetstraße 4, 8. NACO near-infrared adaptive optics image from 2006. 85599 Parsdorf, Germany 9. Composite sub-mm (ALMA, in red), visible light (Hubble Space Telecope in green) and Chandra X-ray image (in blue) of the current appearance, and released for the 30th anniversary. Unless otherwise indicated, all images See ESO Picture of the Week potw1709 for details. in The Messenger are courtesy of ESO, except authored contributions which Credits: 1–8 all ESO | 9. ALMA: ESO/NAOJ/NRAO/A. Angelich; are courtesy of the respective authors. Hubble: NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) © ESO 2017 and P. Challis (Harvard-Smithsonian Center for Astrophysics); ISSN 0722-6691 Chandra: NASA/CXC/Penn State/K. Frank et al.