Abstracts of Large Programmes and Public Spectroscopic Surveys scheduled in Period 106

This list of OPC approved Large Programmes (LPs) is updated every observing period.



We propose to obtain several new MUSE Deep Fields of $t_{\mathrm{exp}} = 25^{\mathrm{h}}$ in blank-sky locations with ultra-deep HST multiband imaging and other ancillary data available. Our selected targets are the four parallel fields of the Hubble Frontier Fields legacy programme that are accessible to the VLT. Our observing strategy is guided by a combination of several science drivers: (1) Obtain spatially resolved spectroscopy of typical Lyman-$\alpha$ haloes at redshifts $z>3$, to constrain the physical nature of the halo gas and the dominant powering mechanism for the Ly$\alpha$ radiation. (2) Identify significant overdensities in the distribution of Ly$\alpha$ emitters and test previous claims that Lyman-$\alpha$ halo properties depend on the environment. (3) Build a statistically significant sample of galaxies out to $z\simeq 1$ for spatially resolved kinematic and dynamical analyses. These new observations will triple the number of MUSE Deep Fields, provide statistically independent locations to combat cosmic sample variance, and substantially improve in image quality over our previous deep fields efforts through the use of Ground-Layer Adaptive Optics. The new Deep Fields will be embedded in small mosaics of $2^{\mathrm{h}}$--$5^{\mathrm{h}}$ depth to mitigate edge effects, characterise the environments, and to increase the general legacy value of this survey by covering the full footprints of the HST images.




\veils, the VISTA Extragalactic Infrared Legacy Survey, is a current ESO Public Survey, covering 9 sqrdeg of extragalactic legacy fields with deep, cadenced observations. The innovative aspect of \veils\ is its design enabling the first wide-field $J$ and $Ks$-band extragalactic time domain survey. The goal of this time-domain survey is to use two independent standardisable candles -- type Ia supernovae and AGN dust time-lags -- to significantly improve constraints of cosmological parameters in a complementary way to BAO, weak lensing, or the CMB. In addition, we will search for new members of a recently discovered class of optically-elusive, infrared-bright transients. Progress on the transient and variability science goals of \veils\ has been compromised in the 2018 season by the low data quality and low completion rate of its optical support survey \textit{VOILETTE} (= VEILS OptIcal Lightcurves of Extragalactic TransienT Events). Here we want to use the opportunity of VIRCAM and OMEGACAM being available for another \veils\ observing season to make up for 2018 to successfully complete the science goals of the survey, i.e. (1) discover, classify, and build light curves of new type Ia supernovae, (2) monitor the optical variability of AGN to determine dust time lags, and (3) support identification of infrared transients with and without an optical counterpart.




Combining adaptive optics and interferometric observations results in a considerable contrast gain compared to single-telescope, extreme AO systems. Taking advantage of this, we propose VLTI/GRAVITY observations of all known young giant exoplanets located in the range of 0.1'' to 2'' from their stars. The observations will provide astrometric data of unprecedented accuracy, being crucial for refining the orbital parameters of planets and illuminating their dynamical histories. Furthermore, GRAVITY will measure non-Keplerian perturbations due to planet-planet interactions in multi-planet systems and directly measure masses. Over time, repetitive observations of the exoplanets at medium resolution (R=500) will provide a catalogue of K-band spectra of unprecedented quality, for a number of exoplanets. The K-band has the unique properties that it contains many molecular signatures (CO, H2O, CH4, CO2). This allows constraining precisely surface gravity, metallicity, and temperature, if used in conjunction with self-consistent models like Exo-REM. Further, we will use the parameter-retrieval algorithm petitRADTRANS to constrain the C/O ratio of the planets. Ultimately, we will produce the first C/O survey of exoplanets, kick-starting the difficult process of linking planetary formation with measured atomic abundances.




Herschel imaging surveys of nearby clouds (d < 0.5 kpc) support a filament paradigm for low-mass star formation (SF), whereby Jeans-type fragmentation of 0.1-pc wide supercritical filaments produces < 0.1pc prestellar cores, which then collapse to core-fed protostars. There is mounting evidence, however, that massive prestellar cores may not exist and that high-mass protostars may be clump-fed, gathering mass from parsec-scale hub-filament systems. We propose to use ArT�MiS on APEX, which provides 3.5 times better resolution than Herschel at 350/450 ?m, to achieve, for the first time, an essentially complete survey of the structure of the densest (Av > 40) molecular gas at < 0.1 pc resolution out to d ~ 3 kpc (total survey area ~5.5 deg^2). We wish to i) investigate whether fragmentation of 0.1-pc wide filaments remains the dominant mode of SF beyond the Gould Belt, and ii) clarify where/how the transition between a core-fed and a clump-fed regime of protostellar mass growth occurs.




The Transiting Exoplanet Survey Satellite (TESS) has ushered in a new era in which it is finally possible to study the composition of small exoplanets for several dozen systems. This is because TESS has discovered hundreds of new transiting planets orbiting the nearest and brightest stars over the last two years, which are thus suitable for high-precision radial velocity observations. The KESPRINT consortium has seized this opportunity by characterizing ~25 TESS planets, in terms of mass, radius, and orbital parameters. Here, we seek to extend and expand our HARPS program by doubling the sample of precisely characterized small planets, leading to a total of 70 planets for which the mass will be known with a precision better than 15%. This enhanced sample will allow us to conduct precise comparative planetology by providing reasonably good number statistics for the first time, as well as extending to longer orbital periods and a wider range of stellar parameters than ever before.




A new generation of wide-field sky surveys, some monitoring the sky several times per night, mean we are now in a golden era of transient astronomy. Gathering the ESO community working on supernovae (SNe) and unusual transients into one coherent team, we have revolutionised the exploitation of these surveys, developing efficient synergies with multi-messenger experiments and making the NTT a crucial global facility (100+ papers). We have provided legacy datasets for the electromagnetic counterpart of gravitational waves, the lowest metallicity supernovae, the fastest evolving transients, long-lived supernovae not explained by standard neutrino-driven explosions, as well as unveiled a diversity in the most luminous supernovae. We now propose to continue such spectroscopic follow-up, building on the success of our PESSTO consortium and bridging the gap to the SOXS instrument that will arrive at the NTT in 2021. We will continue to make all reduced data public as we have done so far.




Gamma-ray bursts (GRBs) are the most violent and luminous explosions known in the universe, and drive ultra-relativistic jets shocking the surrounding medium. The evolution of their broadband SEDs and polarisation offer a unique laboratory for exploring physics under these extreme conditions. Their bright afterglows provide ideal backlights for exploring gas in the host and IGM. We propose a multi-faceted, long-term campaign of rapid follow-up bringing together all current users of ESO for GRB observations. The primary goals are: studying short GRBs, thought to be produced by compact object binary mergers that also produce gravitational waves; characterising early galaxies through spectroscopy of long GRBs at z>~6; identifying and performing novel investigations of the brightest and most exceptional events; and enabling statistical studies of enhanced samples. ESO facilities have a key role, and our coordinated strategy aims to maximise efficiency and science return.




Planets orbiting both stars of a binary system -circumbinary planets- are challenging our understanding about how planets are assembled and how their orbits subsequently evolve. We aim to assess how similar and how different the orbital and physical properties of circumbinary planets are to the properties of planets orbiting single stars. Only twelve binary systems are currently known to host circumbinary planets. However, HARPS radial-velocities collected in the past two years have revealed the presence of circumbinary planet candidates in 15 new systems. With this proposal, we request time on HARPS to confirm 15 planetary candidates which can double the total number of known circumbinary systems. We will also search for longer period and lower mass planets on 20 stable systems, and will monitor a sub-sample of 10 bright new binaries identified by TESS and KELT for new candidates.




The evolution of young stars and disks is driven by the interplay of several processes, notably accretion and ejection of material. Critical to correctly describe the conditions of planet formation, these processes are best probed spectroscopically, using the fluxes and profiles of emission lines, and the UV to IR continuum emission shape. HST will devote 500 orbits in 2020-2022 to the ULLYSES public survey of 82 low-mass (M ? 2Msun) young (age<10 Myr) stars at UV wavelengths. These UV spectra will be a unique possibility to have for the first time a comprehensive view of the accretion/ejection processes ONLY IF they will be combined with contemporaneous high-resolution and flux-calibrated optical to near-IR spectra. We propose to create an unprecedented dataset with contemporaneous ESPRESSO/UVES spectra to spectrally resolve the kinematics of lines, and X-Shooter flux-calibrated spectra to derive extinction, stellar properties, and the fundamental parameters that HST cannot provide.




Fast radio bursts (FRBs) have in the last few years emerged as a rich field for the study of compact objects, magnetized plasma, galaxy formation, and cosmology. Now, technical advances are shifting the emphasis from discovery science to robust statistical analysis. With this Large Programme, we will leverage the imaging and spectroscopic capabilities of the VLT to perform the first large and homogeneous survey of FRB host galaxies. With a sample of 50 FRBs defined by strict selection criteria, we will address two primary science goals: 1) test the leading FRB progenitor models and emission mechanisms through detailed measurements of their host galaxy environments, examining their connection to the underlying stellar population and interstellar medium; and 2) combine FRB dispersion measures and redshifts to assess the distribution of baryons in the low-redshift intergalactic medium and thereby constrain the processes of feedback during galaxy formation. For this, we rely on deep images to identify the hosts, complete redshift determinations, and spectroscopic and photometric data to characterize the stellar populations and physical properties of the hosts. This dataset will set the benchmark for all future FRB surveys and will lay the foundation for numerous follow-up activities. As such, we will rapidly disseminate the data and results to the community through publications and dedicated repositories.




This VST monitoring program is part of an ongoing effort to measure H0 to 1% using the time delays in 40 strongly lensed quasars, including 28 quadruply imaged quasars. This single-step technique needs no complex calibration and provides robust constraints on H0. A 1% measurement of H0 will both clarify the current discrepancy in H0 between CMB and local measurements with Cepheids and Supernovae and improve the FoM of any stage-IV survey by 40%. In practice, we will finish in P108 our ongoing high-cadence (daily) and high-SNR (1000) R-band monitoring of lensed quasars to measure new time delays in 10 systems to <2% in 1 year, complementing current monitoring with the MPIA 2.2m, VST telescopes at ESO and with NOT at La Palma. With the same VST data, we will build mass maps for each field with weak lensing, allowing to detect any mass clump along the lines-of-sights down to ?_ext~0.02. Together with existing and approved HST data, the VST time delays and weak lensing maps will allow us to meet our final goal of 40 time-delay lenses by the end of P108.




High-fidelity spectroscopy and high-precision radial velocities are an essential technique to obtain accurate planetary masses, radii and densities, while also enabling for the atmospheric characterization of these planets. We pursue one of the main science goals of the ESPRESSO GTO: the detection and characterization of Earth-mass planets (possibly) inside the habitable zone of G, K and M stars. We address it with 3 sub-programs: (1) An intensive search for habitable rocky planets in a sample of the most suitable stars ? some of which already hosting planets ? in the solar neighbourhood. (2) A survey for exoplanetary atmospheres through transit and reflected-light spectroscopy, exploiting the unique spectroscopic capabilities of ESPRESSO and the collecting area of the UTs. (3) A follow-up of the most challenging, low-mass planetary candidates from K2 and TESS missions to obtain their precise densities. This proposal covers the third year of ESPRESSO GTO (exoplanetary case).




We propose to explore with HARPS the inner region of planetary systems orbiting nearby G & K dwarfs known to host giant planets beyond the ice-line. Probing the global architecture of planetary systems is extremely challenging, and there is a very limited number of systems for which the planetary content of both the inner and outer parts have been explored. This leads to poor observational constraints on planet formation theories. Actually, the two main branches of formation theories, in-situ formation and inward-migration, predict radically different occurrences of close-in super-Earths and Neptune-type planets in presence of a cold giant. The former anticipates a correlation between the populations of close-in low-mass planets and cold giants, while the latter predicts an anti-correlation. In this LP, we aim to determine the occurrence of close-in super-Earths and Neptunes in systems hosting a cold giant. Recently, several attempts to estimate this occurrence have lead to contradictory results due to small number statistics and biases. Here, we take advantage of the 22-year-long CORALIE radial velocity survey, composed of 1647 main sequence G & K dwarfs limited in volume at 50 pc, to select a sub-sample of 50 stars known to host a giant planet beyond 1 AU. Among these 50 systems, only 5 targets have been intensively monitored by HARPS so far, and 15 are currently being monitored as part of a running GTO programme (not related to this proposal). We propose to monitor the 30 remaining systems, with a total of 75 HARPS measurements per target, to search for low-mass close-in planets. We show that our sample size combined to the proposed observing strategy will allow for a robust determination of the occurrence of close-in super-Earths and Neptunes with cold giants and settle the question of the correlation between these populations. It will thus provide a fundamental observational constraints on planet formation theories.




We propose to conduct a major survey of about 1.4 Sq. Deg. in the COSMOS field with CONCERTO to map in 3D the fluctuations of the [CII] line intensity, in the reionisation and post-reionisation epoch. Our survey will exploit a technique known as "intensity mapping" which probes cosmic structures by measuring the aggregate line emission from all galaxies across redshift. The [CII] line is a promising choice for its brightness and its role as a tracer of diffuse gas and star-formation activity in the interstellar medium. Our survey will give the first constraints on the power spectrum of [CII]-emitting galaxies at z ? 5, allowing us to measure the typical halo mass scale of star-forming galaxies, the star formation rate density, and the number counts of [CII]-emitters as a function of redshift. The average interstellar medium conditions in high-z galaxies will be investigated using cross-power spectra of the [CII] line with the other lines present in the CONCERTO bandpass ([OI] 145 ?m, [NII] 122 ?m and [NII] 205 ?m). Cross-correlation and synergies with galaxy surveys will be used for foreground removal and will provide additional astrophysical information, as on early metal enrichment and global history of reionization. Finally, our survey will simultaneously observe the CO and [CI] intensity fluctuations arising from z ? 2.5 galaxies, giving the spatial distribution and abundance of molecular gas at cosmic noon. We will measure the amount of molecular gas, its distribution in the cosmic web, as well as its physical conditions and excitation properties, which are essential in our understanding of galaxy evolution. On this topic, immediate results are guaranteed.




Ultra-diffuse galaxies (UDGs) are extreme low-surface brightness (LSB) galaxies (?g ? 24 mag/arcsec^2) with a size of several kpc, up to that of the Milky Way, with at least 100 times smaller stellar masses. Despite the increasing number of studies on UDGs, mainly on imaging data, their observed structural properties do not fit in a single formation scenario. Therefore, questions are still open regarding their formation processes and dark matter (DM) content. We propose a large project to obtain the first homogeneous integral-field spectroscopic survey of UDGs in a cluster environment with MUSE. The target is the Hydra I cluster, at ~50Mpc, where a complete sample of UDG candidates, made by 32 objects in total, have been recently discovered inside 0.6 virial radius of the cluster. With the MUSE data we will confirm their cluster membership, measure their stellar kinematics and stellar populations. The stellar population properties (ages and metallicity) together with the baryonic versus DM fraction will be used in comparison with hydrodynamical models of UDGs to establish their formation channels as a function of their location in the cluster. The MUSE data will also establish the GC population and their specific frequency within 1.5Re for each UDG. This will provide an independent handle on the DM content in these systems. To date, due to their LSB nature, similar studies are available only for about 20 UDGs in total, mainly in the Coma cluster, and only few UDGs have integral-field spectroscopy. By doubling the number of spectroscopically studied UDGs and obtaining a homogeneous survey of these extreme LSB galaxies in the Hydra I cluster, the LEWIS project aims at addressing the open actively debated issues on the UDG nature and formation in a cluster environment.




The galaxy environment density often appears as a dominant driving factor shaping the properties of galactic systems. Understanding which processes act and their relative importance call for a uniform deep survey of the large-scale structure, which will provide key observables needed to probe the clusters assembly histories. Since 2013, the VEGAS project was part of an ambitious campaign which is meant to address such points: this is a deep, multi-band (ugri) imaging survey carried out with the VLT Survey Telescope (VST). VEGAS has clearly demonstrated that the wide field-of-view, high efficiency and spatial resolution of OmegaCAM@VST, combined with the long integration time and specifically designed observing strategy, provide an excellent way to map the galaxy structure down to the low surface brightness (LSB) regime (?g~30 mag/arcsec^2). This proposal builds on the success of VEGAS aiming to exploit the unique capabilities offered by OmegaCAM@VST in its last semester of planned operations. The new observations will complement existing VEGAS data and provide a uniform deep survey of the large-scale structure around the Eridanus complex of galaxies that is part of the Fornax-Eridanus super-cluster. The existing data already include the densest regions of Eridanus and Fornax. With the new data we will map the unexplored regions connecting filaments and voids between these dense structures, where infall and virialisation of matter takes place. Our observational dataset will provide a unique way to trace the infall of groups into clusters, and study the pre-processing of the galaxies in filaments and voids before they fall into the cluster core. By comparing observations with theoretical predictions from state-of-the art simulations, this dataset will furthermore to constrain the assembly history of the super-clusters and the role of physical processes acting in different environmental density regimes.




A handful of planets have recently been revealed residing deep inside the hot Neptunian desert, a region of parameter space devoid of planets due to photoevaporation and tidal interactions. The source of the growing population of in-desert planets is still unsolved, and questions remain over the typical internal properties of close-in planets more widely. The intense irradiation in the desert simplifies internal structure modelling, reducing degeneracies and allowing the planetary core mass, heavy element budget, and rock/ice mass fraction to be determined, all critical parameters for understanding a planet's formation and migration history. We propose to precisely measure the masses and bulk densities of ~30 planets in the Neptunian desert by targeting bright candidates from the TESS photometric survey which are vetted with follow-up photometry and spectroscopy. This will substantially increase the sample of highly irradiated planets with precisely measured masses. Our targets span the range from terrestrial to gas-rich planets, allowing precise comparative planetology by providing a sample of planet masses and bulk densities measured in a uniform fashion across the breadth of the desert. The resulting total of ~80 in-desert planets, with masses measured to at least 20% precision, will allow an in-depth investigation into the origin of these planets and directly reveal the distribution of ice-mass and heavy element fractions of close-in planets in the desert for the first time. All of our targets have had independent followup of their planetary transit made from the ground, in combination with low-resolution spectroscopy and high resolution imaging ruling out the most significant false positive scenarios. The hot Neptunes we will characterise represent ideal targets for atmospheric characterisation with JWST, bridging the gap between the hot Jupiter and terrestrial planet regimes of composition and circulation.




Thanks to a new generation of wide-field sky surveys, some monitoring the sky several times per night, we are now in a golden era of transient astronomy. Gathering the ESO community working on supernovae (SNe), gamma-ray bursts (GRBs) and nuclear transients into one coherent team allows for a revolution in the exploitation of these surveys. Developing efficient synergies with multi-messenger experiments and exoplanet survey satellites makes the NTT a crucial global facility for transient astronomy (100+ papers with NTT data in recent years). NTT spectroscopic surveys have provided legacy datasets for the electromagnetic counterpart of gravitational waves, the lowest metallicity supernovae, the fastest evolving transients, long-lived supernovae not explained by standard neutrino-driven explosions, unveiled a diversity in the most luminous supernovae, as well as probing the observational diversity of the tidal disruption events. We now propose to continue such spectroscopic follow-up, building on the success, experience and efficiency of what done so far and bridging the gap to the SOXS instrument that will arrive at the NTT in 2022 (commissioning) and commence scientific operations in 2023. We will make all reduced data public as done by previous NTT spectroscopic surveys.




Multimessenger astronomy, the detection of an astrophysical source in more than one ``messenger'' (photons, gravitational waves, neutrinos), offers an entirely new way to study the Universe. The first detection of gravitational waves combined with electromagnetic radiation from the merger of a binary neutron star in August 2017 marks the start of a new era in which information about the behaviour of mass from gravitational waves are coupled with constraints on the transfer and release of energy from electromagnetic light. ESO facilities played a pivotal role in the counterpart's discovery and characterisation, delivering spectacular photometric and spectroscopic sequences with great diagnostic power. Here we propose a comprehensive programme of X-shooter, FORS, HAWK-I and MUSE imaging, spectroscopic and polarimetric observations of new electromagnetic counterparts found during the year-long O4 campaign of LIGO/Virgo (start mid-2022). These observations will determine, in detail, the make-up of material ejected in the mergers testing if merging binaries create some, most or all of the heaviest elements seen in nature. They will dissect the physics of the explosion, measuring its geometry and the contribution of fast and slow ejecta. They will measure redshifts and independent electromagnetic distances, enhancing the science return for fundamental physics and cosmology.




Asymmetric planetary nebulae (PN) are generally believed to form via the interaction of a companion with the circumstellar environment (CSE) of asymptotic giant branch (AGB) stars. However, on the AGB, evidence for this interaction has only been observed towards a handful of objects and overall the mass-loss process from AGB stars is regarded as spherically symmetric. MIDI surveys of the onset of AGB stellar winds reveal a morphological complexity which could either be interpreted as intrinsic to the stellar wind from a single star, or as induced by a binary companion. In order to (re)solve the origin of the complexity, the imaging capabilities of VLTI/MATISSE are needed. Here, we seek to image the dust forming region of 10 AGB stars to answer: 1. what is the astrophysical cause of the interferometric asymmetries? 2. what is the dust formation history and wind mechanism for single versus binary stars?



Last update: OPO - August 4, 2021