As previously announced, after nearly half a century in publication, ESO’s journal for science and technology, The Messenger, is making a jump into the digital world by becoming an online-only publication. As reader habits have continued to shift online along with journal publication practices, and with sustainability an ever greater focus at ESO, The Messenger has evolved accordingly. Readers will now be able to find both new and old issues of the historic journal at a new redesigned webpage, making the published articles in The Messenger more accessible, usable and traceable than before. 

Under its remit to “Advise Council and the Director General on policy matters of scientific and technical importance related to the planning and operation of ESO”, the STC had its 102^nd meeting on 17 and 18 April in Vitacura, Chile. The agenda included the updates on current and future ESO facilities. As always the STC was deeply impressed by the high level of activity at all of ESO’s observatories -ALMA, ELT and Paranal/La Silla.

Please note that the initial deadline to submit proposals for scientific workshops at ESO in 2024 has been extended until 17 May 2023, due to technical reasons.

MAVIS (MCAO-Assisted Visible Imager and Spectrograph) successfully passed its preliminary design review at the end of March. MAVIS is intended to be installed at the Nasmyth A focus of the VLT UT4 in 2030 (replacing Hawk-I/GRAAL), and is made of two main parts: an Adaptive Optics (AO) system that cancels the image blurring induced by atmospheric turbulence, and its post focal instrumentation, an imager and an IFU spectrograph, both covering the visible part of the light spectrum.

The ALMA partnership is organizing a conference to commemorate its first decade of science operations. The conference will take a look back at the observatory accomplishments, highlight its latest results and look forward to future technical developments. It will take place from 4 to 8 December 2023 in Puerto Varas, Chile. Abstract submission and registration for the conference is now open at the conference webpage with a deadline for abstract submission on the 31st of May 2023. 

UltraVISTA is an ultra-deep near-infrared survey of the central region of the COSMOS field. The fifth UltraVISTA data release comprises stacked images in YJHKs and NB118 narrow-band filters, as well as single-band and dual-mode source lists. The data release also contains a five-band merged catalogue, created from the individual Ks-selected source lists. The release is based on the observations carried out from December 2009 to mid 2019, corresponding to 81125 individual images. This is three years more than DR4. The additional data have almost homogenised the exposure time in the “deep” and “ultra-deep” stripes in the J, H and Ks filters, which now reach the same depths to ∼0.15 mag.

The conference “Two in a million” - The interplay between binaries and star clusters will be held at ESO Garching, Germany, between 11-15 September 2023. Both in-person and online participation will be possible. Please note that the list of invited speakers has been updated.

The deadline for submission of abstracts has been postponed to Monday, 1st June 2023 and the organisers are welcoming contributed talks from researchers who have used ESO imaging survey datasets, but also broader community working on imaging surveys that put the legacy of VIRCAM and OmegaCAM surveys in perspective. Furthermore, the current list of invited speakers as well as the registration fees for in-person participants are now available on the workshop’s website.

The release of the MUSE Hubble Ultra-Deep Field survey (Programmes 094.A-0289(B), 095.A-0010(A), 096.A-0045(A), 096.A-0045(B) and 1101.A-0127, PI R. Bacon) includes the deepest spectroscopic survey ever performed. The MUSE mosaic data cubes, with their 3D content, amazing depth, wide spectral range, and excellent spatial and medium spectral resolution, are rich in information. The 3σ point-source flux limit of an unresolved emission line reaches 3.1×10^-19 and 6.3×10^-20 erg s^-1 cm^-2 at 10- and 141-hour depths, respectively. The redshifts of 2221 sources have securely been identified and measured. With the exception of eight stars, the collected sample consists of 25 nearby galaxies (z < 0.25), 677 [O ii] emitters (z = 0.25 - 1.5), 201 galaxies in the MUSE redshift desert range (z = 1.5 - 2.8) and 1308 Lyα emitters (z = 2.8 - 6.7). This represents an order of magnitude more than the collection of all spectroscopic redshifts obtained before MUSE in the Hubble ultra-deep field area (i.e., 2221 versus 292). At high redshift (z > 3), the difference is even more striking, with a factor of 65 increase (1308 versus 20).

The NIRPS instrument, a cryogenic adaptive-optics equipped high-resolution (R=80,000) spectrograph newly installed on La Silla 3.6-m telescope has successfully entered operation at the start of the new period, on April 1st. The instrument is equipped with a stabilized Fabry-Perot calibration source ensuring high radial velocity precision, with a goal of reaching 1m/s. NIRPS targets M-dwarfs since their so-called habitable zones are closer than for stars like our Sun, and so the orbital periods of planets are shorter than the orbital period of Earth, on the order of weeks instead of a year.