The Messenger

The Messenger is ESO’s journal for science and technology. It serves as a link between ESO and its broad astronomical community by providing information about scientific, technical, and other developments. It also delivers relevant news about astronomy and astrophysics to a broader public, including policy-makers, government officials, journalists, teachers, and amateur astronomers, as well as to interested scientists from other fields.

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Issue 183
Messenger Issue 183

The Messenger Issue 183

Highlights include:

  • Waelkens, C., Benz, W. et al.: ESO Strategy for the 2020s
  • Maire, A., Chauvin, G. et al.: High-precision Astrometric Studies in Direct Imaging with SPHERE
  • Iodice, E., Spavone, M. et al.: The VST Early-type GAlaxy Survey: Exploring the Outskirts and Intra-cluster Regions of Galaxies in the Low-surface- brightness Regime

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Table of Content No. 183 | 2021
Waelkens, C., Benz, W. et al.
ESO Strategy for the 2020s
ADS BibCode: 2021Msngr.183....3W
Waelkens, C., Benz, W., Barcons, X.

Maire, A., Chauvin, G. et al.
High-precision Astrometric Studies in Direct Imaging with SPHERE
ADS BibCode: 2021Msngr.183....7M
Maire, A., Chauvin, G., Vigan, A., Gratton, R., Langlois, M., Girard, J., Kenworthy, M., Pott, J., Henning, T., Kervella, P., Lacour, S., Rickman, E., Boccaletti, A., Delorme, P., Meyer, M., Nowak, M., Quanz, S., Zurlo, A.
Orbital monitoring of exoplanetary and stellar systems is fundamental for analysing their architecture, dynamical stability and evolution, and mechanisms of formation. Current high-contrast extreme- adaptive-optics imagers like the Spectro- Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE), the Gemini Planet Imager (GPI) and the Subaru Coronagraphic Extreme Adaptive Optics/Coronagraphic High Angular Resolution Imaging Spectrograph combination (SCExAO+CHARIS) explore the population of giant exoplanets and brown dwarf and stellar companions beyond typically 10 au, but they cover only a small fraction (< 20%) of the orbit, leading to degeneracies and biases in the orbital parameters. Precise and robust measurements of the position of the companions over time are critical, requiring good knowledge of the instrumental limitations and dedicated observing strategies. The homogeneous dedicated calibration strategy for astrometry implemented for SPHERE has facilitated high-precision studies by its users since it began operating in 2014. As the precision of exoplanet-imaging instruments is now reaching milliarcseconds and is expected to improve with forthcoming facilities, we initiated a community effort, triggered by the SPHERE experience, to share lessons learned for high-precision astrometry in direct imaging. A homogeneous strategy would strongly benefit the Very Large Telescope (VLT) community, in synergy with VLT Interferometer instruments like GRAVITY/GRAVITY+ and future instruments like the Enhanced Resolution Imager and Spectrograph (ERIS) and the MCAO-Assisted Visible Imager and Spectrograph (MAVIS), and in preparation for the exploitation of the Extremely Large Telescope’s (ELT’s) first instruments: the Multi-AO Imaging CAmera for Deep Observations (MICADO), the High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI), and the Mid-infrared ELT Imager and Spectrograph (METIS).

Maud, L., Villard, E. et al.
Enhancing ALMA’s Future Observing Capabilities
ADS BibCode: 2021Msngr.183...13M
Maud, L., Villard, E., Takahashi, S., Asaki, Y., Bastian, T., Cortes, P., Crew, G., Fomalont, E., Hales, A., Ishii, S., Matthews, L., Messias, H., Nagai, H., Sawada, T., Schieven, G., Shimojo, M., Vila-Vilaro, B., Biggs, A., Petry, D., Phillips, N., Paladino, R.
With each observing cycle at the Atacama Large Millimeter/submillimeter Array (ALMA) new features and observing modes are offered. Here we provide some background about how these new capabilities are tested and then made available to ALMA users. These activities help to drive the cutting-edge science conducted with ALMA and to maintain ALMA’s position as the foremost interferometric array operating at millimetre and submillimetre wavelengths. We focus in particular on opening up high-frequency observing using ALMA’s longest baselines, which offers the highest possible angular resolution.

Boffin, H., Derie, F. et al.
FORS-Up: May the FORS Be With Us For Another 15 Years
ADS BibCode: 2021Msngr.183...18B
Boffin, H., Derie, F., Manescau, A., Siebenmorgen, R., Baldini, V., Calderone, G., Cirami, R., Coretti, I., Del Valle Izquierdo, D., Di Marcantonio, P., Gutierrez Cheetham, P., Haddad, N., Hopgood, J., Kolsmanski, J., Modigliani, A., Lilley, P., Moehler, S., Nonino, M., Rupprecht, G., Silber, A.
The FORS Upgrade project (FORS-Up) will extend the life of the popular workhorse instrument attached to ESO’s Very Large Telescope (VLT), FORS2. The project — a collaboration between ESO and INAF–Astronomical Observatory of Trieste — aims to bring to the telescope, in about three years’ time, a refurbished instrument with a new scientific detector, upgraded instrument control software and electronics based on ESO’s Extremely Large Telescope (ELT) standard technologies, a new calibration unit, and additional filters and grisms.

Coccato, L., Freudling, W. et al.
Colour Transformations for ESO Near-Infrared Imagers
ADS BibCode: 2021Msngr.183...20C
Coccato, L., Freudling, W., Retzlaff, J.
ESO operates four near-infrared (NIR) imagers, namely the High Acuity Wide-field K-band Imager (HAWK-I), the VISTA InfraRed CAMera (VIRCAM), the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE), and Son OF ISAAC (SOFI). In addition, data for the two decommissioned instruments the Infrared Spectrometer And Array Camera (ISAAC) and the Nasmyth Adaptive Optics System/COudé Near-Infrared CAmera combination (NAOS-CONICA, or NACO) are available from the science archive. Because these instruments have different effective bandpasses, the magnitudes measured with them are difficult to compare and doing so can lead to inconsistencies if the colour of an object is not taken into account. In this article, we present colour transformations between the ESO NIR imagers and the Two Micron All-Sky Survey (2MASS) photometric system in the J, H, and Ks bands. The coefficients can be used to compare and convert magnitudes derived from different ESO and non-ESO instruments.

Astronomical Science
Iodice, E., Spavone, M. et al.
The VST Early-type GAlaxy Survey: Exploring the Outskirts and Intra-cluster Regions of Galaxies in the Low-surface- brightness Regime
ADS BibCode: 2021Msngr.183...25I
Iodice, E., Spavone, M., Capaccioli, M., Schipani, P., Arnaboldi, M., Cantiello, M., D’Ago, G., De Cicco, D., Forbes, D., Greggio, L., Krajnović, D., La Marca, A., Napolitano, N., Paolillo, M., Ragusa, R., Raj, M., Rampazzo, R., Rejkuba, M.
The VST Early-type GAlaxy Survey (VEGAS) is a deep, multi-band (u, g, r, I) imaging survey, carried out with the 2.6-metre VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile. VEGAS combines the wide (1-square- degree) field of view of the VST’s OmegaCAM imager and long integration times, together with a specially designed observing strategy. It has proven to be a gold mine for studies of features at very low surface brightness, down to levels of μg ~ 27–30 magnitudes arcsec–2, over 5–8 magnitudes fainter than the dark sky at Paranal. In this article we highlight the main science results obtained with VEGAS observations of galaxies across different environments, from dense clusters of galaxies to unexplored poor groups and in the field.

Astronomical News
Burtscher, L., Ivanov, V. et al.
Report on the ESO Workshop "Ground-based Thermal Infrared Astronomy — Past, Present and Future"
ADS BibCode: 2021Msngr.183...31B
Burtscher, L., Ivanov, V., van den Ancker, M.
This ESO workshop was originally planned as a traditional in-person meeting at ESO in Garching in April 2020. It was rescheduled and transformed into a fully online event in light of the COVID-19 pandemic. With 337 participants from 36 countries the workshop was a resounding success, demonstrating the wide interest of the astronomical community in the science goals and the toolkit of ground-based thermal infrared (IR) astronomy.

Sbordone, L., Pritchard, J. et al.
Report on the ESO Workshop "20th Anniversary of Science Exploration with UVES"
ADS BibCode: 2021Msngr.183...37S
Sbordone, L., Pritchard, J., Pasquini, L., Hill, V., Kaufer, A., Ledoux, C., Percheron, I., Peroux, C., Primas, F., Saldias, L.
The UltraViolet-Visual Echelle Spectrograph (UVES) was first offered to the ESO community in 2000. A workhorse covering a vast range of topics from Solar System objects to cosmology, it quickly became one of the most productive instruments at Paranal. For the 20th anniversary of UVES’s entering into service, over 100 astronomers from across the world convened in a virtual workshop to celebrate the instrument’s achievements and to reframe its role, in a profoundly changed instrumental and scientific landscape, as it enters its 3rd decade of operation at the Very Large Telescope (VLT).

Solarz, A.
Fellows at ESO
ADS BibCode: 2021Msngr.183...41E
Solarz, A.

Kalliopi Koutoulaki, M.
External Fellows at ESO
ADS BibCode: 2021Msngr.183...42E
Kalliopi Koutoulaki, M.

Personnel Movements
ADS BibCode: 2021Msngr.183...43E