ESO operates four near-infrared (NIR) imagers, namely the High Acuity Widefield K-band Imager (HAWK-I), the VISTA InfraRed CAMera (VIRCAM), the SpectroPolarimetric 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 archive1. 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 nonESO instruments.
compact galaxy with a size a factor of ~ 4 smaller than local massive galaxies (the so-called “red nuggets”). Then a second, prolonged phase, dominated by mergers and gas inflows, is responsible for the structural evolution and size growth from z ~ 1 to today. The ultra-compact objects formed at high redshift likely end up forming the cores of giant local galaxies, whilst subsequently accreted or newly formed stars remain preferentially in the external regions. Unfortunately, this “accreted” material overlaps, along the line of sight, with the spatial and orbital distributions of the in-situ pristine light that encodes the information about high-z baryonic processes, irreversibly limiting our resolving power and hampering our ability to study the early phases of galaxy formation. Luckily, since merging is a stochastic phenomenon, a small fraction of red nuggets survives intact until the present day, without experiencing any merger or interaction and thus remaining as massive and ultra-compact as they formed: relic galaxies (Trujillo et al., 2009). Since a detailed study of the stellar populations of high-z red nuggets would require prohibitive integration times with the currently available facilities, relics are the only systems that allow us to study the physical processes that shaped the mass assembly of massive galaxies in the high-z Universe in the amount of detail currently reachable only for the nearby Universe. Chiara Spiniello 1, 2 Crescenzo Tortora 2 Giuseppe D’Ago 3 Nicola R. Napolitano 5, 2 and the INSPIRE Team
Here we focus in particular on two IXTs. The first, the Integrated Science Operations Team, or ISOpT, is tasked with defining and optimising the end-to-end workflow of science operations, from proposal preparation to data reduction and user support. The team develops and implements policies governing global science operations and is responsible for delivering the full package of science operations tasks. The ultimate goal is to provide an effective, efficient and homogeneous global user experience in order to maximise high-quality and transfor mational science. The team also acts on issues that are raised through various channels, including ALMA staff from the ALMA Regional Centres (ARCs) and the JAO.
The Atacama Large Millimeter/submi-llimeter Array (ALMA) comprises 66 antennas working as a powerful interferometer. High-speed digitisation, signal transmission over several tens of kilo-metres from the receivers to the corre-lator, and complex data processing all require state-of-the-art technologies. The ALMA2030 Development Roadmap calls for an increase in the bandwidth by at least a factor of two, implying a major upgrade of the entire signal path. We present here the results of a detailed study looking at how to upgrade the ALMA digital system, including digitisation, data pre-processing, and data transmission to cope with bandwidths more than four times the current ones. At the same time, this system will contribute to increasing the nominal correlation efficiency from 88% to 99%, and prepare ALMA for longer baselines of up to 100 kilometres.
In the coming decade, up to 100 000 satellites in large constellations could be launched into low Earth orbit. The satellites will introduce a variety of negative impacts on astronomy observatories and science, which vary from negligible to very disruptive depending on the type of instrument, the position of the science target, and the nature of the constellation. Since the launch of the first batch of SpaceX's Starlink constellation in 2019, the astronomy community has made substantial efforts to analyse the problem and to engage with satellite operators and government agencies. This article presents a short summary of the simulations of impacts on ESO's optical and infrared facilities and ALMA, as well as the conducted observational campaigns to assess the brightness of satellites. It also discusses several activities to identify policy solutions at the international and national level.
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) 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 mu_g 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.
From 22 to 26 June 2020, we hosted ESO's first live e-conference, #H02020, from within ESO headquarters in Garching, Germany. Every day, between 200 and 320 researchers around the globe tuned in to discuss the nature and implications of the discord between precise determinations of the Universe's expansion rate, H0. Originally planned as an in-person meeting, we moved to the virtual domain to maintain strong scientific discourse despite the SARS-CoV-2 (COVID-19) pandemic. Here, we describe our conference setup, participants feedback gathered before and after the meeting, and lessons learned from this unexpected exercise. As e-conferencing will become increasingly common in the future, we provide our perspective on how e-conferences can make scientific exchange more effective and inclusive, in addition to climate friendly.
The Multi-adaptive optics Imaging CamerA for Deep Observations (MICADO) will image a field of view of nearly 1 arcminute at the diffraction limit of the Extremely Large Telescope (ELT), making use of the adaptive optics correction provided by single-conjugate adaptive optics (SCAO) and multi-conjugate adaptive optics (MCAO). Its simple and robust design will yield an unprecedented combination of sensitivity and resolution across the field. This article outlines the characteristics of the observing modes offered and illustrates each of them with an astrophysical application. Potential users can explore their own ideas using the data simulator ScopeSim.
MAORY is the adaptive optics module for ELT providing two gravity invariant ports with the same optical quality for two different client instruments. It enable high angular resolution observations in the near infrared over a large field of view (~1 arcmin2 ) by real time compensation of the wavefront distortions due to atmospheric turbulence. Wavefront sensing is performed by laser and natural guide stars while the wavefront sensor compensation is performed by an adaptive deformable mirror in MAORY which works together with the telescope's adaptive and tip tilt mirrors M4 and M5 respectively.
The powerful combination of the cutting-edge multi-object spectrograph MOSAIC with the world largest telescope, the ELT, will allow us to probe deeper into the Universe than was possible. MOSAIC is an extremely efficient instrument in providing spectra for the numerous faint sources in the Universe, including the very first galaxies and sources of cosmic reionization. MOSAIC has a high multiplex in the NIR and in the VIS, in addition to multi-Integral Field Units (Multi-IFUs) in NIR. As such it is perfectly suited to carry out an inventory of dark matter (from rotation curves) and baryons in the cool-warm gas phases in galactic haloes at z=3-4. MOSAIC will enable detailed maps of the intergalactic medium at z=3, the evolutionary history of dwarf galaxies during a Hubble time, the chemistry directly measured from stars up to several Mpc. Finally, it will measure all faint features seen in cluster gravitational lenses or in streams surrounding nearby galactic halos, providing MOSAIC to be a powerful instrument with an extremely large space of discoveries. The preliminary design of MOSAIC is expected to begin next year, and its level of readiness is already high, given the instrumental studies made by the team.
