More than 1100 studies with ESO data published in 2025

Around 1150 studies using data collected at ESO’s observatories were published last year — the second year in a row that publications have exceeded 1100. It also marks the ninth consecutive year where observations at ESO’s facilities have led to more than 1000 published studies annually. The ESO Library, Documentation, and Information Services Department have updated their publication statistics to include 2025 with a detailed breakdown of the contributions from each ESO facility [1].

As in previous years, data from ESO’s Very Large Telescope (VLT) and the VLT interferometer (VLTI) have dominated in publications, contributing to around 670 studies in 2025. The facilities’ broad range of instruments, plus the location at Paranal Observatory in Chile’s Atacama Desert — a site with unique observing conditions including pristine dark skies — make them a flagship in ground-based astronomy. The Multi Unit Spectroscopic Explorer (MUSE) continues its six-year streak as the most productive VLT/I instrument, with data in over 200 papers. A highlight from MUSE last year was the publication of an ultra-detailed thousand-colour image of the Sculptor Galaxy. Another highlight from the VLT published last year used data from the Ultraviolet and Visual Echelle Spectrograph (UVES), the second most productive VLT instrument with over 120 papers in 2025, to find a planet in a perpendicular orbit to a pair of stars.

The survey facilities, ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) and the VLT Survey Telescope (VST) [2], also found at Paranal Observatory, produced data for over 100 papers. Data from ESO’s first observatory, La Silla, contributed to about 200 studies last year, an increase from 177 in 2024. This shows how the observatory remains at the forefront of research, especially thanks to instruments such as HARPS, High Accuracy Radial velocity Planet Searcher, on ESO’s 3.6-metre telescope.

The Atacama Large Millimeter/Submillimeter Array (ALMA), co-owned by ESO, provided data for over 550 publications in 2025. Around half of these papers relied on observing time granted to astronomers based in Europe. Highlights of ALMA studies published last year include the discovery of oxygen in the most distant known galaxy and observations of the creation of a new solar system. Located next to ALMA, observations from the Atacama Pathfinder Experiment (APEX), which was operated and hosted by ESO until the end of 2025, led to around 45 papers last year. Of these, close to 20 used data obtained during ESO observing time.

A record number of publications employed data from the ESO Science Archive Facility, with around 530 papers relying partly or exclusively on archival data. This also made 2025 the year with the highest percentage of ESO publications using the archive, at 46%, underscoring the value of legacy observations in cutting-edge astronomical research. Furthermore, over a quarter of all 2025 publications relied on archival data alone, without any ESO observations obtained by the authors themselves.

The impressive publication numbers emphasise the significant role ESO plays in helping astronomers advance our understanding of the Universe. This is made possible thanks to the work of the wider astronomical community and ESO staff, the advanced technology of ESO’s facilities, and the continued support of ESO’s member states and of Chile.

Notes

[1] Papers can use data from more than one facility, therefore the total number cannot be calculated by adding all publications of the individual sites.

[2] The VST project was a joint venture between ESO and the Capodimonte Astronomical Observatory, part of the Italian National Institute for Astrophysics (INAF). As of 1 October 2022, this is a sole project of INAF, hosted by ESO at Paranal. Only papers based (entirely or partly) on ESO VST time are included in the statistics.

More Information

The statistics presented here are derived from the ESO Telescope Bibliography (telbib), a database of refereed papers published by the ESO users community. Telbib is developed and curated by the ESO Library, Documentation, and Information Services Department. While text-mining scripts are applied when screening the literature for ESO data papers, articles are carefully examined by the curators before they are added to the database to ensure that all telbib papers use partly or exclusively data from ESO facilities for which observing time was recommended by ESO. The public telbib interface provides visualisations of search results including on-the-fly graphs and predefined charts.

Courtesy of European Southern Observatory