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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Latest Issue
Messenger Issue 192

The Messenger Issue 192

Highlights include:

  • Cirasuolo, M., Tamai, R. et al.: The Rise of the Giant: ESO’s Extremely Large Telescope
  • Martinez, P., and the ELT Team: ESO’s Extremely Large Telescope Dome and Main Structure Update
  • Vernet, E., Cayrel, M. et al.: ESO’s Extremely Large Telescope Optics Update
  • Mendel, J., Harborne, K. et al.: Mapping Galaxy Transformation with the MAGPI Survey
  • Colless, M., Cirasuolo, M. et al.: Paranal Instrumentation Plan Lessons Learned 2023

Read the full PDF

Past Issues
Messenger Issue 191
2023Issue 191
Messenger Issue 190
2023Issue 190
Messenger Issue 189
2022Issue 189
Messenger Issue 188
2022Issue 188
Messenger Issue 187
2022Issue 187
Messenger Issue 186
2022Issue 186
Messenger Issue 185
2021Issue 185
Messenger Issue 184
2021Issue 184
Messenger Issue 183
2021Issue 183
Messenger Issue 182
2021Issue 182
Messenger Issue 181
2020Issue 181
Messenger Issue 180
2020Issue 180
Messenger Issue 179
2020Issue 179
Messenger Issue 178
2019Issue 178
Messenger Issue 177
2019Issue 177
Messenger Issue 176
2019Issue 176
Messenger Issue 175
2019Issue 175
Messenger Issue 174
2018Issue 174
Messenger Issue 173
2018Issue 173
Table of Content No. 192 | 2024
ELT progress
Cirasuolo, M., Tamai, R. et al.
The Rise of the Giant: ESO’s Extremely Large Telescope
ADS BibCode: 2024Msngr.192....3C
Cirasuolo, M., Tamai, R., Koehler, B., Biancat-Marchet, F., Gonzáles Herrera, J., and the ELT Team
The European Southern Observatory’s Extremely Large Telescope (ESO’s ELT) stands as the cornerstone of ESO’s ambitious vision to build a new facility capable of providing a paradigm shift in our understanding of the cosmos. ESO’s ELT is swiftly advancing towards completion, having surpassed, in June 2023, the 50% completion milestone. Possessing unparalleled sensitivity and angular resolution thanks to its 39-metre main mirror, ESO’s ELT holds the potential to revolutionise our perspective on the Universe, from the exploration of exoplanets to the detailed study of stellar populations, and from unravelling the mysteries of galaxy evolution to probing fundamental physics and cosmology.

Martinez, P., and the ELT Team
ESO’s Extremely Large Telescope Dome and Main Structure Update
ADS BibCode: 2024Msngr.192....4M
Martinez, P., and the ELT Team
In the ongoing saga of constructing an 80-metre-high dome and an expansive telescope structure for ESO’s Extremely Large Telescope (ELT), the narrative unfolds as a testament to human resilience and determination. Originating from a contract signed in 2016, the Dome and Main Structure (DMS) project has survived financial restructuring, partner bankruptcy and global upheaval caused by the COVID-19 pandemic and market fluctuations that resulted in a complex contractual and commercial situation. The DMS project includes the construction of both the internal telescope structure that supports the telescope mirrors and the instruments, as well as the external dome that provides protection against the harsh conditions of the Atacama Desert. Following the design phase, the project started with the construction of the foundations and of the gigantic dome. In September 2023 a new chapter began, marked by the start of the construction of the telescope structure, a phase demanding an unprecedented level of precision and constant supervision by the ESO team on site. The design, born from a collaboration of many disciplines, is now consolidated and frozen, setting the stage for a race against time to achieve the highest possible level of quality demanded by the ‘biggest eye on the sky’.

Vernet, E., Cayrel, M. et al.
ESO’s Extremely Large Telescope Optics Update
ADS BibCode: 2024Msngr.192....6V
Vernet, E., Cayrel, M., Cirasuolo, M., Tamai, R., Forster, A., Haupt, C., Mueller, M., Pettazzi, L., Pirard, J., Sqalli, O., Tuti, M., and the ELT Team
The Extremely Large Telescope is at the core of ESO’s vision to deliver the largest optical and infrared telescope in the world. We present an updated status report on the five mirrors of the telescope, focusing on the challenges and the progress made in the last few years.

Astronomical Science
Mendel, J., Harborne, K. et al.
Mapping Galaxy Transformation with the MAGPI Survey
ADS BibCode: 2024Msngr.192...11M
Mendel, J., Harborne, K., Lagos, C., Wisnioski, E., and the MAGPI team
The Middle Ages Galaxy Properties with IFS (MAGPI) survey is an ongoing ESO Large Programme combining medium-deep Multi Unit Spectroscopic Explorer (MUSE) observations and an extensive library of simulated data to understand galaxy assembly over the past four billion years of cosmic time. Thanks to the combination of MUSE and the GALACSI adaptive optics system, MAGPI is delivering spatially resolved kinematic, star formation, and stellar population maps for hundreds of galaxies at intermediate redshift. By targeting galaxies across a range of environments, MAGPI will provide a unique perspective on the physical mechanisms responsible for transforming galaxy morphologies and kinematics at late cosmic times.

Vink, J., Crowther, P. et al.
X-Shooting ULLYSES: Massive Stars at Low Metallicity
ADS BibCode: 2024Msngr.192...16V
Vink, J., Crowther, P., Fullerton, A., Garcia, M., Martins, F., Morrell, N., Oskinova, L., St Louis, N., ud-Doula, A., Sander, A., Sana, H., Bouret, J., Kubatova, B., Marchant, P., Martins, L., Wofford, A., van Loon, J., Telford, O., Götberg, Y., Bowman, D., Erba, C., Kalari, V., and The XShootU Collaboration
The Hubble Space Telescope has devoted 500 orbits to observing 250 massive stars with low metallicity in the ultraviolet (UV) range within the framework of the ULLYSES program. The X-Shooting ULLYSES (XShootU) project enhances the legacy value of this UV dataset by providing high-quality optical and near-infrared spectra, which are acquired using the wide-wavelength- coverage X-shooter spectrograph at ESO’s Very Large Telescope. XShootU emphasises the importance of combining UV with optical spectra for the consistent determination of key stellar parameters such as effective temperature, surface gravity, luminosity, abundances, and wind characteristics including mass-loss rates as a function of metallicity. Since uncertainties in these parameters have implications across various branches of astrophysics, the data and modelling generated by the XShootU project are poised to significantly advance our understanding of massive stars at low metallicity. This is particularly crucial for confidently interpreting James Webb Space Telescope (JWST) data of the earliest stellar generations, making XShootU a unique resource for comprehending individual spectra of low-metallicity stars.

Telescopes and Instrumentation
Colless, M., Cirasuolo, M. et al.
Paranal Instrumentation Plan Lessons Learned 2023
ADS BibCode: 2024Msngr.192...23C
Colless, M., Cirasuolo, M., Andersen, A., Bernstein, R., Egner, S., Hill, V., Monnier, J., Mérand, A.
The 2023 Paranal Instrumentation Programme Lessons Learned exercise assessed the recent major projects delivered to Paranal. The goal was to identify good practices and improvements for the future by examining cost, schedule, and performance against targets. The review also considered ESO’s response to the previous exercise and lessons learned from interactions with partner institutes in Europe. This article summarises the overall findings and key recommendations for ESO.

Abad, J., Aguilera, B. et al.
Infrastructure Upgrade of UT1, UT2 and UT3 for the Implementation of Laser Guide Stars for the GRAVITY+ Project
ADS BibCode: 2024Msngr.192...31A
Abad, J., Aguilera, B., Alarcon, P., Alvarez, I., Alvial, L., Atton, E., Beltran, A., Barraza, I., Barriga, P., Bedigan, H., Benimelli, C., Booth, M., Briones, O., Candia, R., Caniguante, L., Capocci, R., Cardenas, C., Cardenas, D., Chala, A., Contreras, R., Conzelmann, R., Delboulbé, A., Delplancke, F., Diaz, J., Doberti, A., Engelhardt, M., Fernandez, J., Fuenteseca, E., Garcia, F., Garrido, C., Garrido, P., Gonté, F., Guidolin, I., Gutierrez, P., Guzman, R., Hackenberg, W., Juica, Y., Kirkmann, D., Kirchbauer, J., Krempl, P., Lorenzo, J., Mella, A., Meza, Y., Miranda, F., Nunes, S., Nurzia, V., Oberti, S., Olivares, F., Opazo, M., Riquelme, M., Salgado, F., Scherbarth, M., Rochat, S., Rojas, E., Schuhler, N., Tamblay, I., Tamblay, R., Unmanzor, E., Vega, H., Villanueva, F., Whilem, R., Woillez, J., Zúñiga, L., Zúñiga, J., On behalf of the GRAVITY+ Collaboration
The GRAVITY+ project encompasses the upgrade of the Very Large Telescope Interferometer infrastructure and of the GRAVITY instrument to improve sky coverage, high-contrast capabilities, and faint science. The sky coverage is obtained by the use of one laser guide star on each Unit Telescope, but it first required an upgrade of the infrastructure of the telescopes, carried out over the last 18 months.

Pompei, E., Ivanov, V. et al.
Goodbye SOFI and Thanks for 25 Years of Data!
ADS BibCode: 2024Msngr.192...36P
Pompei, E., Ivanov, V., Lidman, C., Saviane, I., Vanzi, L.
15 August 2023 was the last night of observation with Son OF Isaac (SOFI) at the New Technology Telescope (NTT) in La Silla. The following day, the instrument was warmed up and removed from the NTT’s Nasmyth A focus, in preparation for Son Of X-Shooter (SOXS) to be installed in its place.

Lo Curto, G., Pepe, F. et al.
HARPS at 20: Evolving Through Continuous Improvements
ADS BibCode: 2024Msngr.192...38C
Lo Curto, G., Pepe, F., Fleury, M., Hughes, I., Schnell, R., Wimmer, V., Fuerte Rodriguez, P., Silber, A., Saviane, I., Lovis, C., Sosnowska, D., Dumusque, X., Jakob, G., Accardo, M.
The High Accuracy Radial velocity Planet Searcher (HARPS), operational since October 2003, has been pioneering exoplanetary research, with over 1300 publications and more than 200 exoplanet detections, and is still in high demand. Its continued success has been achieved thanks to its extraordinary stability, the continuous improvement of its data reduction pipeline and the integration of innovative technologies whenever they became available. Here we report on the recent maintenance mission to enhance the detector’s cryostat reliability and thermal stability. Additionally we tested a novel cryogenic concept on HARPS, and the positive outcome of the test opens up new possibilities.

Astronomical News
Jerabkova, T., Primas, F. et al.
Report on the ESO workshop "Peer Review Under Review"
ADS BibCode: 2024Msngr.192...43J
Jerabkova, T., Primas, F., Patat, F., De Cia, A., Kerzendorf, W., Strolger, L., Kissler-Patig, M., Carpenter, J., Bolamperti, A., Cacciapuoti, L., Faress, G., De Simone, M., Hoppe, E., Itrich, D., Oplistilova, A., Rubio, A., Tako, D., Toci, C.
The workshop Peer Review Under Review, held at ESO Headquarters in Garching, Germany from 6 to 10 February 2023, marked a significant milestone, being the first conference focusing on peer review within the astronomical community. This unique gathering not only convened representatives from many of the major astronomical organisations but also drew experts from such diverse fields as computer science, social sciences, statistics, meta-research, and other relevant domains. This unique group of experts critically examined the current state of peer review in the scientific community. This report summarises the presentations and discussions, and the conclusions that emerged during the workshop.

Zwaan, M., Bonaldi, A.
Report on the ESO workshop "Coordinated Surveys of the Southern Sky"
ADS BibCode: 2024Msngr.192...48Z
Zwaan, M., Bonaldi, A.
How can two major organisations dedicated to ground-based astronomy work together to maximise the science impact of their astronomical surveys? This was the topic for the Coordinated Surveys of the Southern Sky symposium, jointly organised by ESO and the Square Kilometre Array Observatory between 27 February and 3 March 2023. The aims of the symposium were to raise awareness across the respective communities of survey capabilities and to build liaisons in preparation for synergetic surveys, as well as for multi-wavelength follow-up programmes.

Díaz Trigo, M., Maccarone, T. et al.
Report on the EAS Special Session "The Millimeter Transient Sky: Present Opportunities and Perspectives"
ADS BibCode: 2024Msngr.192...51T
Díaz Trigo, M., Maccarone, T., Tetarenko, A.
Time-domain astronomy was identified as a key science area in the US Astro2020 Decadal Survey and is one of the active support areas of ASTRONET. Consistent with these priorities, dedicated facilities are being constructed for studying the variable sky. However, at millimeter wavelengths, only recently have such studies lifted off thanks to the advent of the Atacama Large Millimeter/submillimeter Array (ALMA), with unprecedented sensitivity, and of upgrades of other existing millimetre observatories. The advances in this field and how to overcome the associated challenges were the subject of a special session at the 2023 European Astronomical Society Annual Meeting.

Wisnioski, E., Mendel, T.
Report on the Australia–ESO conference "Galaxy Transformation Across Space and Time — the Third Australia–ESO meeting"
ADS BibCode: 2024Msngr.192...54W
Wisnioski, E., Mendel, T.
We report on the third joint Australia–ESO conference since the commencement of the strategic partnership between Australia and ESO. The conference was supported by ESO, the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), the Australian National University, and the International Centre for Radio Astronomy Research. The meeting focused on new results from ongoing surveys and simulations of galaxies and their evolution. The motivations for upcoming facilities such as the Multi-conjugate adaptive optics-Assisted Visible Imager and Spectrograph (MAVIS), the Square Kilometre Array (SKA), Vera C. Rubin Observatory, and the Wide-field Spectroscopic Telescope and the new science opportunities and collaborations that they will enable were discussed. The meeting achieved a gender-balanced participant list and strove to provide an inclusive environment. It was a pleasure to share science again in person since the last joint Australia–ESO conference in February 2020. While there was some flexibility for inclusion purposes, the meeting prioritised in-person attendance with only five remote talks.

Kamann, S., Bodensteiner, J.
Report on the ESO workshop "Two in a Million — The Interplay Between Binaries and Star Clusters"
ADS BibCode: 2024Msngr.192...57K
Kamann, S., Bodensteiner, J.
A substantial fraction of cosmic star formation happens in star clusters, and the binary populations therein are shaped by interactions amongst themselves and with other cluster stars. The intricate interplay of star clusters and the binary stars they host was the topic of this workshop, which brought together about 150 scientists working on four cornerstones of modern astrophysics: star formation, stellar evolution, cluster dynamics, and gravitational waves. As well as invited reviews and contributed talks, the scientific programme offered breakout sessions focused on various practical skills linked to the workshop theme. Informal poster-viewing sessions concluded the session days and offered the opportunity for extended discussions about recent results as well as future instruments.

Klencki, J., Nielsen, L.
Fellows at ESO
ADS BibCode: 2024Msngr.192...59E
Klencki, J., Nielsen, L.