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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

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.

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’.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

ADS BibCode: 2024Msngr.192...59E

Klencki, J., Nielsen, L.

The Messenger Issue 192