Abstracts of Large Programmes scheduled in Period 112

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



We propose to continue and complete our deep NaCo $L^{\prime}$-band coronagraphic angular differential imaging GTO survey for wide-separation giant planets around nearby young stars with circumstellar disks. Our main goal is the revelation and characterisation of the observationally not yet well-characterised wide-separation \mbox{($>$5-10\,au)} giant planet population during the time of formation and dynamical evolution. Our survey is therefore focused on stars with protoplanetary transition disks and with well-characterised debris disks, many of which show signatures of dynamical activity that could indicate the presence of giant planets. With the combination of $L^{\prime}$-band observations, the use of the AGPM coronagraph to minimise the inner working angle for bright stars, and a strategy for going significantly deeper than previous surveys, we optimise the sensitivity to both more embedded (younger) as well as cooler (lower-mass and older) planets than targeted by previous/other surveys. We also probe smaller separations, thus bridging the gap between orbital separations probed by RV and previous direct imaging surveys. Our GTO survey is distinguished from and complementary to other state-of-the-art exoplanet imaging surveys like SPHERE-SHINE by the focus on stars with planet formation-related circumstellar disks and by covering a different parameter range by exploiting the unique $L^{\prime}$-band capability of NaCo.



van de Sande

Due to the complexity of internal and external processes acting on disk galaxies, many outstanding questions regarding their evolution remain. Our Milky Way provides an unparalleled view of disk evolution, revealing a complex history of minor accretion coupled with internal processes. However, building a comprehensive framework of galaxy evolution from a single object is unrealistic. Instead, we propose to extend Galactic methods to the wider galaxy population, reaping the benefits of detailed Milky Way studies, while probing the diverse mechanisms of galaxy evolution. Edge-on galaxies are ideal for this task: they allow us to disentangle the assembly history imprinted in thick disks and provide the greatest insights into outflows. We propose the GECKOS (Generalising Edge-on galaxies and their Chemical bimodalities, Kinematics, and Outflows out to Solar environments) survey: a representative sample of 35 edge-on galaxies with MUSE, going out to larger radius, deeper (S/N>40 at ? = 23.5 mag/arcsec^2), and with higher spatial resolution (<200 pc) than existing IFS nearby galaxy surveys. Extensive vertical and radial coverage is essential for detecting imprints of minor accretion and outflows. GECKOS will deliver 2D measurements of stellar abundance, age, and kinematics, as well as ionised gas metallicities, ionisation parameters, and outflow kinematics; all core ingredients for chemical evolution models. Our program is optimally designed to determine the assembly histories and properties of galaxies across a large range of SFRs, B/T ratios, and boxy and non-boxy bulges. GECKOS is transformative in two ways: (1) it moves deep studies of edge-on galaxies from single objects to controlled samples, enabling a census of physical properties, and (2) it allows us to apply the chemical evolution models designed for the Milky Way to a range of galaxies. With GECKOS, we will reveal the variation in key physical processes that govern the assembly and evolution of disk galaxies.




We propose MAUVE (MUSE and ALMA Unveiling the Virgo Environment), a large MUSE program designed to shed light on the obscure evolution of the inner discs of cluster galaxies, which typically still host significant cold gas reservoirs after their first pericentre passage, and reveal how star formation ceases in these systems. We will map the full extent of the molecular gas disc (as traced by ALMA observations already at hand) of 40 late-type Virgo cluster galaxies at various infall stages using MUSE. These data will provide stellar and ionised gas kinematics and distributions, star-formation rates, and metal enrichment maps at ~100-200 pc scale, allowing us to investigate the link between cold gas and star formation when and where environmental processes are at play, and as a function of infall time. We will reconstruct detailed star-formation histories for a representative sample of cluster galaxies for the first time, assess the role and impact of outflows, and deliver a rich multi-wavelength data set with a huge legacy value for environmental studies, which no other sample currently available can provide.




This proposal aims at confirming exceptional habitable-zone (HZ) Super-Earth candidates orbiting bright nearby Sun-like stars. Our team has recently re-analyzed all the HARPS archival data using a new tool that allows to correct for instrumental, stellar and telluric systematics and delivers radial-velocities (RVs) that are on average 30% more precise. We then searched for new planetary signals using a novel, more robust, optimal detection criterion, which lead to the detection of a dozen of planetary candidates including 5 HZ Super-Earths. Such planets orbiting bright nearby Sun-like stars (< 15pc and > 0.5 solar masses) are extremely difficult to detect, because the transit, astrometry, microlensing and direct imaging detection techniques are not sensitive to them. However, finding such planets is crucial as they would be the best targets for future missions aiming at characterizing the atmosphere of Earth-like planets through reflected light. Such planets can only be found and confirmed using the RV method in the near future, by following-up promising candidates in RV blind-search surveys. We propose here to follow-up the 5 HZ Super-Earth candidates found in our re-analysis with the HARPS spectrograph. HARPS is preferred over ESPRESSO as the amount of time requested to confirm these long-period, small amplitude planetary signals would be very difficult to schedule on ESPRESSO, and because our realistic simulations show that HARPS precision is good enough. Currently, there is at most only one Super-Earth in the HZ of a nearby Sun-like star (tau cet e) and this detection is strongly call into question by our analysis. We estimate that our program should confirm 3.6 � 0.9 HZ Super-Earths, which would open new perspectives for the field of exoplanets. The 340 hours of time requested to follow-up 5 targets seems huge, however, this is the only way we can confirm such exceptional targets in the near future.




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 offers a unique laboratory for exploring physics under these extreme conditions. Their bright afterglows provide ideal backlights for detailed analysis of gas in their hosts and the intergalactic medium across cosmic time. 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 and their accompanying kilonovae, thought to be produced by compact object binary mergers, and hence key to understanding r-process cosmic chemical evolution; detailed characterisation of early galaxies through spectroscopy of long GRBs at z>~5; identifying and performing novel investigations of the brightest and most exceptional events; and enabling statistical studies of enhanced samples, for example, constraining the evolution of the ionizing escape fraction from massive stars. ESO facilities have a central role, and our coordinated strategy aims to maximise efficiency and science return. The launch of the Chinese/French SVOM satellite in 2023 promises a step change in the rate of well-localised GRBs, and, thanks to its powerful on-board optical telescope, our ability to identify high priority targets. At the same time, new spectrographs on 2.5-4m telescopes (SOXS at the NTT and NTE at the NOT) will take the strain of obtaining redshifts for more average bursts, while our programme is tailored to complement these developments by exploiting the VLTs for the most challenging and important events.




High-resolution time-series spectroscopy datasets are an unparalleled window to understand the chemistry and dynamics of exoplanet atmospheres and their orbital architectures. With its high spectral resolution, stability, and broad wavelength coverage, NIRPS is at the forefront to deliver precise chemical inventories, T-P profiles, mass-loss rates, as well as dynamical and orbital constraints. By dedicating 225 nights to time-series spectroscopy, the NIRPS consortium will study the atmospheres of a population of exoplanets spanning large ranges in mass, radius, irradiation, age, and host star spectral type. This will reshape the field towards population-based studies built on a uniform data acquisition, reduction, and analysis strategy. By the GTO's end, these high signal-to-noise high-fidelity spectra will shift the paradigm of exoplanet atmospheric chemistry and dynamics, formation, and evolution models for the next decades. We present here the first step of this long-term project.




Mass measurements of transiting exoplanets are key for constraining their internal structure and probe their atmosphere through transit spectroscopy. Kepler and TESS surveys have shown that planets smaller than 4 Earth radius, that is, super-Earths and mini-Neptunes are the most common type of exoplanets in the solar neighborhood. These small planets are characterized by a bimodal distribution whose origin is unclear but probably related to various thermally-driven atmospheric escape mechanisms. We propose an extensive program of mass characterization of small transiting exoplanets orbiting mid- to late-type M dwarfs, mostly from TESS. Our program will notably: 1) pave the mass-radius diagram of multi-planetary systems, 2) provide ultra-precise (10%) mass measurements of a sub-sample of rocky planets with the goal of constraining their core mass fraction and 3) provide mass measurements of a sub-sample of temperate small planets amenable to atmospheric characterization with JWST.




The blind radial-velocity search of exoplanets around low-mass (LM) stars and ultra-cool dwarfs, proposed as part of the NIRPS GTO, is an ambitious, comprehensive, and feasible project to understand the process of planet formation and to identify golden Earth-like planets for future in-depth characterization. Thanks to the unique capacities of NIRPS spectrograph we propose to detect the not-yet discovered planetary systems orbiting the closest M dwarfs, which are the best systems for future study of their atmospheres in analysing their reflected light by the new generation of facilities. Secondly our objective is to explore the sensitivity of planet formation to the initial conditions in the protoplanetary disk by searching for planets around a set of ultra-cool dwarfs and young LM stars. Finally our goal is to characterize the global architecture of planetary systems around M dwarfs, which is crucial to comprehend their formation history.




Our current understanding about the origin and diversity of planetary systems is limited by the paucity of well-studied long-period exoplanets with properties largely unaltered since their formation. Warm giant planets are less affected by their host star and can be used to test planetary formation and evolution models. We aim at characterizing warm giant transiting planets (4 - 15 Rearth) orbiting bright stars. Most of our targets were identified in TESS data through single transit events, or through two events separated by ~2 years. We propose to undertake the crucial task of measuring their orbital periods, eccentricities, and masses via precise radial velocities using HARPS and to schedule complementary ground-based photometric observations to re-observe the transit. We will study and interpret these objects in the context of planet formation models. Such targets form the link between hot Jupiters and solar-system giants and will be ideal targets to measure detailed atmospheric chemistry of cooler transiting planets.




The majority of known exoplanets orbit within 30 days around their star. These planets can undergo complex atmospheric and dynamical processes, such as losing a substantial fraction of their atmosphere or migrating toward the star outside of their original orbital plane. Neptune-size planets appear to be particularly sensitive to these processes, as evidenced by the Neptunian desert and savanna, respectively a definite lack of hot Neptunes at short orbital periods and a milder deficit of warm Neptunes at longer periods. This makes close-in Neptunes targets of choice to investigate evolutionary processes. While atmospheric erosion plays a major role in shaping Neptunian worlds, it is not clear how far into the savanna this process is active and when in a planet life it occurs. Determining the fraction of planets brought close-in by early disk-driven or late high-eccentricity migration, and whether these processes spread close-in Neptunes evenly or bring them preferentially to the desert or savanna, is thus essential to understand their overall evolution. These two dynamical pathways are expected to yield different 3D orbital architectures, and indeed the few existing measurements of obliquity (the angle between stellar spin and planetary orbital normal) for close-in Neptunes hint at a dichotomy between the desert and savanna. We therefore propose a large census of obliquities within the volume-limited sample of close-in Neptunes, observing their transits with the VLT/ESPRESSO. The combination of large photon-collecting power and high spectral resolution will allow us to unveil the Rossiter-McLaughlin signal of these small gas giants, ie the distortion of the stellar lines induced by their transit, which traces the orientation of their orbit. Our program will increase obliquity measurements fourfold in a regime whose exploration has just begun, allowing us to determine the frequency of aligned/misaligned Neptune systems and their dependence to star/planet properties. We will constrain formation and evolution models with the derived obliquity distributions to rewind the dynamical history of close-in Neptunes and its impact on their atmospheric evolution. The atmospheric screening naturally yielded by our measurements will further provide the community with a large catalog of Neptune candidates to follow-up with the JWST and ground-based spectrographs.




We propose to conduct a comparative study of the architecture of planetary systems orbiting nearby G & K dwarfs with and without giant planets beyond the ice line. The proposed study shall be conducted with the HARPS and ESPRESSO spectrographs. 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. Currently, 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 the 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 with or without a cold giant. Recently, several attempts to estimate these occurrences have led to contradictory results due to small number statistics and biases. Here, we take advantage of two decades-long historical radial velocity surveys conducted on the HARPS and CORALIE spectrographs, composed of 2487 main sequence G & K dwarfs and limited in volume at 57pc. From this well defined sample, we select two equal-sized populations of stars, with 52 stars known to host at least one giant planet beyond 0.5 AU, and 55 who do not harbor any giant planets. Using archival ESO and private data, we show that using the combination of 50 HARPS and 25 ESPRESSO RV measurements with historical lower precision RVs is sufficient to probe and characterize the architecture of low mass planetary systems for periods shorter than 100 days and masses as low as 3 M_Earth. Among these 107 nearby G & K dwarfs, 52 stars have already been intensively monitored by HARPS (50 meas. or more) but almost none have ESPRESSO RVs. We propose in the LP to increase the minimum number of HARPS RVs to 50 for the 55 remaining systems, and for half of the total sample, to obtain 25 ESPRESSO measurements. 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 and without cold giants, and settle the question of the correlation between these populations. It will thus provide fundamental observational constraints on planet formation theories.



Forster Schreiber

We propose to continue GALPHYS, a multi-year program begun in P111 to systematically study 50 massive z~1-3 star-forming galaxies at the Toomre scale (~0.1", 1 kpc), the fundamental scale of global gravitational instabilities and star formation complexes in gas-rich rotationally-supported galactic disks. Very deep, high spatial and spectral resolution Ha+[NII]+[SII] AO-assisted ERIS/IFU observations will map the kinematics, outflows, star formation, and ionized ISM conditions. We will measure radial motions and gas transport, the origin of gas turbulence, and the drivers of outflows all at ~1 kpc scales, key to elucidate early bulge + disk formation and growth regulation in massive galaxies. This 2-yr LP will deliver the largest census of typical log(M*/Msun)>10 galaxies at 1kpc and R~10500 resolution; deeper data are planned in future periods. GALPHYS will uniquely constrain the main internal physical processes driving galaxy evolution.




Quasar absorption lines provide a key diagnostic of many aspects of astrophysics including: deriving fundamental physics and cosmology, studying chemical enrichment of the Universe, and tracing the evolution of gas over a vast range of densities and environments across cosmic time. The unprecedented combination of extremely precise wavelength calibration, high spectral resolution and high sensitivity of the ESPRESSO spectrograph has finally enabled observations that can start addressing several open questions that will constrain both state-of-the-art cosmological simulations of galaxy evolution and theoretical stellar nucleosynthetic yields. Our proposed legacy survey has been designed to tackle several outstanding questions in cosmology and astrophysics: constraining fundamental physics in terms of the properties of dark matter, precisely measuring the temperature and metallicity of both intergalactic and circumgalactic gas at high redshifts and constraining isotopic ratios of C and Mg to pinpoint the relative contribution of stellar populations in the early Universe. We are requesting a large program of 186 hours to observe 23 quasars between redshifts 3.3 and 4.3 in order to address these science goals. While we are proposing to address these key science questions, this program is designed to provide a legacy sample of deep spectra in order to showcase ESPRESSO capabilities to the quasar absorption line community whilst providing epoch measurements for the key science goals of upcoming spectroscopic instrumentation on the next generations of telescopes.




New observations of gravitational waves, exotic supernovae & gamma-ray bursts, and early galaxies take us ever further into the low-metallicity high-redshift Universe. Key to these phenomena are massive stars -- the progenitors of compact objects and powerful stellar explosions. Spectroscopic monitoring of massive stars in the Galaxy and the Large Magellanic Cloud (LMC) induced a paradigm shift: the majority of massive stars interact with stellar companions throughout their lives. These interactions, primarily in the form of mass-transfer, fundamentally alter the evolutionary paths of both stars, and as a consequence, the chemical content and ionising budget of their host galaxies. Models of the Early Universe, of the first stars and galaxies, of compact-object and supernova production, and of gravitational-wave formation across cosmological times fully rely on empirical constraints obtained for massive binaries and multiple systems. The problem: the models should represent the low-metallicity Universe, but the empirical constraints have been derived only for solar and LMC-like (~1/2 solar) metallicities! With this ambitious proposal, we will remedy this issue. Using the unique capabilities of the FLAMES/GIRAFFE instrument, we propose to spectroscopically monitor for the first time an unbiased sample of ~1000 massive stars in the Small Magellanic Cloud (SMC), a nearby dwarf galaxy with a metallicity of ~1/5 solar. The SMC offers the lowest metallicity in which a statistically-significant population of massive stars can be investigated for multiplicity. With 25 epochs spread of 2 yr, and using novel tools of spectral disentangling and atmosphere analysis, we will: 1. firmly establish the binary fraction and orbital configurations of massive stars in the regime relevant for binary interactions (orbital periods up to few years); 2. Provide mass and luminosity measurements for hundreds of massive stars to establish their internal structure, 3. hunt for binary-interaction products, including dormant black holes, to establish the physics of binary interactions and core-collapse physics at low metallicity, 4. Determine the spin distributions of single stars and binaries to establish the links between rotation, star formation, and binary interactions, and 5. Extract the initial mass function and binary mass-ratio distribution of massive stars at low Z. This legacy survey will provide indispensable input to models of massive-star evolution, supernova physics, black hole formation, stellar feedback, and galaxy evolution at low metallicity.




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 (120+ 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 of what has been done so far and bridging the gap to the SOXS instrument that will arrive at the NTT in 2024 and commence scientific operations in 2024-2025. We will make all reduced data public as done by previous NTT spectroscopic surveys.




Early JWST data are already revolutionising our understanding of galaxy formation and evolution at high redshifts. A suite of ambitious JWST GTO and GO programs are embarking upon extensive near- and mid-infrared imaging surveys which will measure with unprecedented detail the properties of galaxies from the nearby Universe back to the earliest cosmic times. To maximise the scientific return, it is essential that these surveys be matched by equally ambitious spectroscopic programmes. We propose a public survey using MUSE to fulfil this aim. Our goal is to construct a MUSE mosaic of a contiguous area of 65 square-arcminute area within the COSMOS / CANDELS region, which is the focus of two major JWST programs: the JWST PRIMER survey and the JWST Emission Line Survey (JELS). The MUSE spectroscopic coverage will provide precise redshifts, UV spectra, measure environments, and identify star formation and AGN activity in galaxies out to z~6. Importantly, MUSE will provide spectra of every galaxy within the surveyed regions, avoiding the photometric pre-selection targeting biases that arise from multi-object spectroscopic programs, while allowing extensive spectral stacking explorations. The survey will obtain spectra for more than 1000 (magnitude-selected) galaxies predicted to detected by PRIMER at 5.5 < z < 6.5 (as well as vast samples of galaxies around cosmic noon), and ~800 emission-line selected galaxies from JELS over 1.5 < z < 6.1. A wide-field, contiguous mosaic will at this depth will also allow us to search for interconnected (large-scale) structures using Ly-alpha. The proposed survey covers more than 7x the sky area of the 3x3 MUSE mosaic in the MUSE-Deep survey (Bacon et al. 2022). It will cover a comparable area to the MUSE-WIDE survey (Urrutia et al. 2019), but in a single field and with 3x the exposure time per pointing (and correspondingly many more redshifts per pointing). Together, the JWST and proposed MUSE observations aim to create the next generation of legacy datasets for which we will explore galaxy evolution for the next decade. In the spirit of the JWST programs, we suggest this be made a public survey and waive all proprietary rights, although we will provide advanced data products to the community both during, and at the end of, the program.




QSOs at z~6 are among the brightest sources in the Universe and are unparalleled tools to investigate the first billion years of Cosmic History. The high density of the infant Universe leads to vigorous episodes of galaxy formation and rapid evolution, which we are only now starting to unveil. With this large program we propose to take the next leap forward in our view of the build up of the first galaxies through a deep (4 hours per target) legacy survey of a sample of 40 bright (M_1450<-26mag) QSOs at z>5.8 already observed with ALMA and XSHOOTER. MUSE will provide a spectroscopy survey along the entire QSO light cones, resulting in the detection of the Ly? emission in ~100 galaxies at 4.0<z<6.6 (the redshift of interest for this program) in a volume of 2.4x10^5 cMpc^3, including 20-30 galaxies physically associated to the central QSOs. Additionally, the proposed observations will be sensitive enough to expose, with unprecedented detail, the diffuse ionized gas in the QSO's immediate environment via its Ly? emission. The unique synergy of three of the most powerful ESO instruments will produce a transformative data-set to address many outstanding questions of early galaxy formation: i) Which environment led to rapid formation of massive black holes in such short cosmic times? ii) How did the first galaxies pollute the gas at intergalactic scales? iii) Which galaxies are responsible for the reionization? More in general, owing to high-quality spectroscopy from the ground, the proposed MUSE observations will provide the most complete view of the first stages of the co-evolution of galaxies with their close environment to date. In addition, JWST is offering an exceptional complement to the proposed observations, by providing exquisite follow-up of the rest-frame optical emission lines for 16 of the proposed targets. The unparalleled combination of MUSE, XSHOOTER, ALMA, and JWST data will be a long lasting legacy, placing the ESO community in a privileged position to undertake the first systematic study of the ISM metallicity (traced by, e.g., oxygen lines), star formation rates (traced by hydrogen recombination lines), ISM properties (traced by ALMA observations), and CGM physical content (traced by metal lines in absorption) and to finally paint a coherent picture of the link between galaxy and halo gas properties in what are poised to become the best studied fields for the CGM-galaxy co-evolution in the first billion years of cosmic history. Setting the stage for further exploration of the epoch of reionization using the E-ELT.

update: OPO - July 26, 2023