The 100 most-cited articles in Astronomy and Astrophysics, 2022

Context. We present the third data release of the European Space Agency’s Gaia mission, Gaia DR3. This release includes a large variety of new data products, notably a much expanded radial velocity survey and a very extensive astrophysical characterisation of Gaia sources. Aims. We outline the content and the properties of Gaia DR3, providing an overview of the main improvements in the data processing in comparison with previous data releases (where applicable) and a brief discussion of the limitations of the data in this release. Methods. The Gaia DR3 catalogue is the outcome of the processing of raw data collected with the Gaia instruments during the first 34 months of the mission by the Gaia Data Processing and Analysis Consortium. Results. The Gaia DR3 catalogue contains the same source list, celestial positions, proper motions, parallaxes, and broad band photometry in the G , G BP , and G RP pass-bands already present in the Early Third Data Release, Gaia EDR3. Gaia DR3 introduces an impressive wealth of new data products. More than 33 million objects in the ranges G RVS < 14…

We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution ( R = 30−330) prism spectroscopy over the wavelength range 0.6–5.3 μm and higher resolution ( R = 500−1340 or R = 1320−3600) grating spectroscopy over 0.7–5.2 μm, both in single-object mode employing any one of five fixed slits, or a 3.1 × 3.2 arcsec 2 integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6 × 3.4 arcmin 2 field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed.

Euclid is a mission of the European Space Agency that is designed to constrain the properties of dark energy and gravity via weak gravitational lensing and galaxy clustering. It will carry out a wide area imaging and spectroscopy survey (the Euclid Wide Survey: EWS) in visible and near-infrared bands, covering approximately 15 000 deg 2 of extragalactic sky in six years. The wide-field telescope and instruments are optimised for pristine point spread function and reduced stray light, producing very crisp images. This paper presents the building of the Euclid reference survey: the sequence of pointings of EWS, deep fields, and calibration fields, as well as spacecraft movements followed by Euclid as it operates in a step-and-stare mode from its orbit around the Lagrange point L2. Each EWS pointing has four dithered frames; we simulated the dither pattern at the pixel level to analyse the effective coverage. We used up-to-date models for the sky background to define the Euclid region-of-interest (RoI). The building of the reference survey is highly constrained from calibration…

In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey we present 120–168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m +44°30′ and 1h00m +28°00′ and spanning 4178 and 1457 square degrees respectively. The images were derived from 3451 h (7.6 PB) of LOFAR High Band Antenna data which were corrected for the direction-independent instrumental properties as well as direction-dependent ionospheric distortions during extensive, but fully automated, data processing. A catalogue of 4 396 228 radio sources is derived from our total intensity (Stokes I) maps, where the majority of these have never been detected at radio wavelengths before. At 6″ resolution, our full bandwidth Stokes I continuum maps with a central frequency of 144 MHz have: a median rms sensitivity of 83 μJy beam−1; a flux density scale accuracy of approximately 10%; an astrometric accuracy of 0.2″; and we estimate the point-source completeness to be 90% at a peak brightness of 0.8 mJy beam−1. By creating three 16 MHz…

Context. The eROSITA X-ray telescope on board the Spectrum-Poentgen-Gamma (SPG) observatory combines a large field of view and a large collecting area in the energy range between ~0.2 and ~8.0 keV. This gives the telescope the capability to perform uniform scanning observations of large sky areas. Aims. SRG/eROSITA performed scanning observations of the ~140 square degree eROSITA Final Equatorial Depth Survey field (the eFEDS field) as part of its performance verification phase ahead of the planned four year of all-sky scanning operations. The observing time of eFEDS was chosen to slightly exceed the depth expected in an equatorial field after the completion of the all - sky survey. While verifying the capability of eROSITA to perform large-area uniform surveys and saving as a test and training dataset to establish calibration and data analysis procedures, the eFEDS survey also constitutes the largest contiguous soft X-ray survey at this depth to date, supporting a range of early eROSITA survey science investigations. Here we (i) present a catalogue of detected X-ray sources in the…

Context. Gaia Data Release 3 ( Gaia DR3) contains the second release of the combined radial velocities. It is based on the spectra collected during the first 34 months of the nominal mission. The longer time baseline and the improvements of the pipeline made it possible to push the processing limit from G RVS = 12 in Gaia DR2 to G RVS = 14 mag. Aims. We describe the new functionalities implemented for Gaia DR3, the quality filters applied during processing and post-processing, and the properties and performance of the published velocities. Methods. For Gaia DR3, several functionalities were upgraded or added to the spectroscopic pipeline. The calibrations were improved in order to better model the temporal evolution of the straylight and of the instrumental point spread function (PSF). The overlapped spectra, which were mostly discarded in Gaia DR2, are now handled by a dedicated module. The hot star template mismatch, which prevented publication of hot stars in Gaia DR2, is largely mitigated now, down to G RVS = 12 mag. The combined radial velocity of stars brighter than or equal…

Context.TheGaiaDR3 catalogue contains, for the first time, about 800 000 solutions with either orbital elements or trend parameters for astrometric, spectroscopic, and eclipsing binaries, and combinations of these three. Aims.With this paper, we aim to illustrate the huge potential of this large non-single-star catalogue. Methods.Using the orbital solutions and models of the binaries, we have built a catalogue of tens of thousands of stellar masses or lower limits thereof, some with consistent flux ratios. Properties concerning the completeness of the binary catalogues are discussed, statistical features of the orbital elements are explained, and a comparison with other catalogues is performed. Results.Illustrative applications are proposed for binaries across the Hertzsprung-Russell Diagram (HRD). Binarity is studied in the giant branch and a search for genuine spectroscopic binaries among long-period variables is performed. The discovery of new EL CVn systems illustrates the potential of combining variability and binarity catalogues. Potential compact object companions are…

We present the PHANGS-MUSE survey, a programme that uses the MUSE integral field spectrograph at the ESO VLT to map 19 massive (9.4 < log(M⋆/M⊙)< 11.0) nearby (D ≲ 20 Mpc) star-forming disc galaxies. The survey consists of 168 MUSE pointings (1′ by 1′ each) and a total of nearly 15 × 106spectra, covering ∼1.5 × 106independent spectra. PHANGS-MUSE provides the first integral field spectrograph view of star formation across different local environments (including galaxy centres, bars, and spiral arms) in external galaxies at a median resolution of 50 pc, better than the mean inter-cloud distance in the ionised interstellar medium. This ‘cloud-scale’ resolution allows detailed demographics and characterisations of H IIregions and other ionised nebulae. PHANGS-MUSE further delivers a unique view on the associated gas and stellar kinematics and provides constraints on the star-formation history. The PHANGS-MUSE survey is complemented by dedicated ALMA CO(2–1) and multi-band HST observations, therefore allowing us to probe the key stages of the star-formation process from molecular clouds…

Context. The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims. This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods. GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP/RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca,…

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP/RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T eff , log g , and [M/H] (470 million using…

Context. Blue (BP) and Red (RP) Photometer low-resolution spectral data are one of the exciting new products in Gaia Data Release 3 ( Gaia DR3). These data have also been used to derive astrometry and integrated photometry in Gaia Early Data Release 3 and astrophysical parameters and Solar System object reflectance spectra in Gaia DR3. Aims. In this paper, we give an overview of the processing techniques that allow raw satellite data of multiple transits per source to be converted into combined spectra calibrated to an internal reference system, resulting in low-resolution BP and RP mean spectra. We describe how we overcome challenges due to the complexity of the on-board instruments and to the various observation strategies. Furthermore, we show highlights from our scientific validation of the results. This work covers the internal calibration of BP/RP spectra to a self-consistent mean instrument, while the calibration of the BP/RP spectra to the absolute reference system of physical flux and wavelength is covered by one of the accompanying Gaia DR3 papers. Methods. We calibrate…

Context.The chemical composition of the Sun is required in the context of various studies in astrophysics, among them in the calculation of standard solar models (SSMs) used to describe the evolution of the Sun from the pre-main-sequence to its present age. Aims.In this work, we provide a critical re-analysis of the solar chemical abundances and corresponding SSMs. Methods.For the photospheric values, we employed new high-quality solar observational data collected with the IAG facility, state-of-the art non-equilibrium modelling, new oscillator strengths, and different atmospheric models, including the MARCS model, along with averages based on Stagger and CO5BOLD 3D radiation-hydrodynamics simulations of stellar convection. We performed new calculations of oscillator strengths for transitions in O I and N I. For O I, which is a critical element with regard to the interior models, calculations were carried out using several independent methods. We investigated our results in comparison with the previous estimates. Results.We find an unprecedented agreement between the new estimates…

Context. The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP/RP spectra. Aims. We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute M G magnitude, radius, distance, and extinction for each star. Methods. GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP/RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP/RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the…

We provide an overview of the capabilities and performance of the Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope when used in its multi-object spectroscopy (MOS) mode employing a novel Micro Shutter Array (MSA) slit device. The MSA consists of four separate 98″ × 91″ quadrants each containing 365 × 171 individually addressable shutters whose open areas on the sky measure 0.20″ × 0.46″ on a 0.27″ × 0.53″ pitch. This is the first time that a configurable multi-object spectrograph has been available on a space mission. The levels of multiplexing achievable with NIRSpec MOS mode are quantified and we show that NIRSpec will be able to observe typically fifty to two hundred objects simultaneously with the pattern of close to a quarter of a million shutters provided by the MSA. This pattern is fixed and regular, and we identify the specific constraints that it yields for NIRSpec observation planning. In particular, the roll angle at which a given NIRSpec MSA observation will be executed will, in most cases, not be known before the observation is actually scheduled.…

Context. One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres. Aims. We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light. Methods. We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could…

The near-infrared spectrograph (NIRSpec) on theJames WebbSpace Telescope (JWST) offers the first opportunity to use integral-field spectroscopy from space at near-infrared wavelengths. More specifically, NIRSpec’s integral-field unit can obtain spectra covering the wavelength range 0.6−5.3 μm for a contiguous 3.1″ × 3.2″ sky area at spectral resolutions ofR ≈ 100, 1000, and 2700. In this paper we describe the optical and mechanical design of the NIRSpec integral-field spectroscopy mode, together with its expected performance. We also discuss a few recommended observing strategies, some of which are driven by the fact that NIRSpec is a multipurpose instrument with a number of different observing modes, which are discussed in companion papers. We briefly discuss the data processing steps required to produce wavelength- and flux-calibrated data cubes that contain the spatial and spectral information. Lastly, we mention a few scientific topics that are bound to benefit from this highly innovative capability offered by JWST/NIRSpec.

Aims. Three-dimensional (3D) maps of Galactic interstellar dust are a tool for a wide range of uses. We aim to construct 3D maps of dust extinction in the Local Arm and surrounding regions. Methods. To do this, Gaia EDR3 photometric data were combined with 2MASS measurements to derive extinction towards stars with accurate photometry and relative uncertainties on EDR3 parallaxes of less than 20%. We applied our hierarchical inversion algorithm adapted to inhomogeneous spatial distributions of target stars to this catalogue of individual extinctions. Results. We present the updated 3D dust extinction distribution and provide an estimate of the error on integrated extinctions from the Sun to each area in the 3D map. The full computational area is similar to the one of the previous DR2 map, that is to say with a 6 × 6 × 0.8 kpc 3 volume around the Sun. Due to the addition of fainter target stars, the volume in which the clouds can be reconstructed has increased. Due to the improved accuracy of the parallaxes and photometric data in EDR3, extinctions among neighbouring targets are more…

Context.The thirdGaiadata release (DR3) provides a wealth of new data products. The early part of the release,GaiaEDR3, already provided the astrometric and photometric data for nearly two billion sources. The full release now adds improved parameters compared toGaiaDR2 for radial velocities, astrophysical parameters, variability information, light curves, and orbits for Solar System objects. The improvements are in terms of the number of sources, the variety of parameter information, precision, and accuracy. For the first time,GaiaDR3 also provides a sample of spectrophotometry and spectra obtained with the Radial Velocity Spectrometer, binary star solutions, and a characterisation of extragalactic object candidates. Aims.Before the publication of the catalogue, these data have undergone a dedicated transversal validation process. The aim of this paper is to highlight limitations of the data that were found during this process and to provide recommendations for the usage of the catalogue. Methods.The validation was obtained through a statistical analysis of the data, a confirmation…

We present a new comprehensive collection of stellar evolutionary tracks and isochrones for rotating low- and intermediate-mass stars assembled with the updated version of PARSEC V 2.0. This version includes our recent calibration of the extra mixing from overshooting and rotation, as well as several improvements regarding the nuclear reaction network, treatment of convective zones, mass loss, and other physical input parameters. The initial mass of the stellar models covers the range 0.09 M ⊙ to 14 M ⊙ for six sets of initial metallicity, from Z = 0.004 to Z = 0.017. Rotation is considered for stars above ∼1 M ⊙ with a smooth transition between non-rotating and extremely fast-rotating models, based on the initial mass. For stars more massive than ∼1.3 M ⊙ , the full rotation range, from low to critical, is considered. We adopt the solar-scaled chemical mixtures with Z ⊙ = 0.01524. All the evolutionary phases from the pre-main-sequence to the first few thermal pulses on the asymptotic giant branch or central C exhaustion are considered. The corresponding theoretical isochrones are…

Context. In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with the general aim of delivering stellar parameters and elemental abundances for large samples of Galactic stars, complementing Gaia astrometry. Among those surveys, the Gaia -ESO Public Spectroscopic Survey, the only one performed on a 8m class telescope, was designed to target 100 000 stars using FLAMES on the ESO VLT (both Giraffe and UVES spectrographs), covering all the Milky Way populations, with a special focus on open star clusters. Aims. This article provides an overview of the survey implementation (observations, data quality, analysis and its success, data products, and releases), of the open cluster survey, of the science results and potential, and of the survey legacy. A companion article reviews the overall survey motivation, strategy, Giraffe pipeline data reduction, organisation, and workflow. Methods. We made use of the information recorded and archived in the observing blocks; during the observing runs; in a number of relevant documents; in the spectra and…

Context.Gaia Data Release 3 contains astrometry and photometry results for about 1.8 billion sources based on observations collected by the European Space Agency (ESA) Gaia satellite during the first 34 months of its operational phase (the same period covered by Gaia early Data Release 3; Gaia EDR3). Low-resolution spectra for 220 million sources are one of the important new data products included in this release. Aims. In this paper, we focus on the external calibration of low-resolution spectroscopic content, describing the input data, algorithms, data processing, and the validation of the results. Particular attention is given to the quality of the data and to a number of features that users may need to take into account to make the best use of the catalogue. Methods. We calibrated an instrument model to relate mean Gaia spectra to the corresponding spectral energy distributions (SEDs) using an extended set of calibrators: this includes modelling of the instrument dispersion relation, transmission, and line spread functions. Optimisation of the model is achieved through total…

Deep images and near-IR spectra of galaxies in the field of the lensing cluster SMACS J0723.3−7327 were recently taken as part of the Early Release Observations (EROs) program of the James Webb Space Telescope (JWST). Among these, two NIRSpec spectra of galaxies, at z = 7.7 and at z = 8.5, were obtained, revealing, for the first time, the rest-frame optical emission line spectra of galaxies in the epoch of reionization, including the detection of the important [O III ] λ 4363 auroral line (see JWST PR 2022-035). We present an analysis of the emission line properties of these galaxies, finding that these galaxies have a high excitation (as indicated by high ratios of [O III ] λ 5007/[O II ] λ 3727, [Ne III ] λ 3869/[O II ] λ 3727), strong [O III ] λ 4363, high equivalent widths, and other properties typical of low-metallicity star-forming galaxies. Using the direct method, we determined oxygen abundances of 12 + log(O/H)≈7.9 in two z = 7.7 galaxies and a lower metallicity of 12 + log(O/H)≈7.4 − 7.5 (∼5% solar) in the z = 8.5 galaxy using different strong line methods. More accurate…

Stellar dynamos generate magnetic fields that are of fundamental importance to the variability and evolution of Sun-like and low-mass stars, and for the development of their planetary systems. As a key to understanding stellar dynamos, empirical relations between stellar parameters and magnetic fields are required for comparison to ab initio predictions from dynamo models. We report measurements of surface-average magnetic fields in 292 M dwarfs from a comparison with radiative transfer calculations; for 260 of them, this is the first measurement of this kind. Our data were obtained from more than 15 000 high-resolution spectra taken during the CARMENES project. They reveal a relation between average field strength, ⟨B⟩, and Rossby number,Ro, resembling the well-studied rotation–activity relation. Among the slowly rotating stars, we find that magnetic flux, ΦB, is proportional to rotation period,P, and among the rapidly rotating stars that average surface fields do not grow significantly beyond the level set by the available kinetic energy. Furthermore, we find close relations…

Context.The thirdGaiadata release (GaiaDR3) contains, beyond the astrometry and photometry, dispersed light for hundreds of millions of sources from theGaiaprism spectra (BP and RP) and the spectrograph (RVS). This data release opens a new window on the chemo-dynamical properties of stars in our Galaxy, essential knowledge for understanding the structure, formation, and evolution of the Milky Way. Aims.To provide insight into the physical properties of Milky Way stars, we used these data to produce a uniformly derived all-sky catalogue of stellar astrophysical parameters: atmospheric properties (Teff, logg, [M/H], [α/Fe], activity index, emission lines, and rotation), 13 chemical abundance estimates, evolution characteristics (radius, age, mass, and bolometric luminosity), distance, and dust extinction. Methods.We developed the astrophysical parameter inference system (Apsis) pipeline to infer astrophysical parameters ofGaiaobjects by analysing their astrometry, photometry, BP/RP, and RVS spectra. We validate our results against those from other works in the literature, including…

Context. The Gaia Early Data Release 3 contained the positions, parallaxes, and proper motions of 1.5 billion sources, some of which did not show a good fit to the ‘single star’ model. Binarity is one of the causes of this. Aims. Four million of these stars were selected and various models were tested to detect binary stars and to derive their parameters. Methods. We used a preliminary treatment to discard the partially resolved double stars and to correct the transits for perspective acceleration. We then investigated whether the measurements show a good fit to an acceleration model with or without jerk. We tried the orbital model when the fit of any acceleration model was beyond our acceptance criteria. We also tried a Variability-Induced Mover (VIM) model when the star was photometrically variable. A final selection was made in order to keep only solutions that probably correspond to the real nature of the stars. Results. Following our analysis, 338 215 acceleration solutions, about 165 500 orbital solutions, and 869 VIM solutions were retained. In addition, formulae for…

Context. With the most recent Gaia data release, the number of sources with complete 6D phase space information (position and velocity) has increased to well over 33 million stars, while stellar astrophysical parameters are provided for more than 470 million sources, and more than 11 million variable stars are identified. Aims. Using the astrophysical parameters and variability classifications provided in Gaia DR3, we selected various stellar populations to explore and identify non-axisymmetric features in the disc of the Milky Way in configuration and velocity space. Methods. Using more about 580 000 sources identified as hot OB stars, together with 988 known open clusters younger than 100 Myr, we mapped the spiral structure associated with star formation 4−5 kpc from the Sun. We selected over 2800 Classical Cepheids younger than 200 Myr that show spiral features extending as far as 10 kpc from the Sun in the outer disc. We also identified more than 8.7 million sources on the red giant branch (RGB), of which 5.7 million have line-of-sight velocities. This later sample allows the…

Context.RR Lyrae stars are excellent tracers of the oldest stars (ages ≳ 9–10 Gyr) and standard candles for measuring the distance to stellar systems that are mainly composed of an old stellar population. TheGaiaThird Data Release (DR3) publishes a catalogue of full-sky RR Lyrae stars observed during the initial 34 months of science operations. They were processed through the Specific Object Study (SOS) pipeline, which was developed to validate and characterise Cepheids and RR Lyrae stars (SOS Cep&RRL) observed byGaia. Aims.The main steps of the SOS Cep&RRL pipeline are described in the documentation and papers accompanying previousGaiadata releases. For DR3, the pipeline was modified in its process: in addition to theGaiamultiband (G,GBP,GRP) time-series photometry, the epoch radial velocities measured for RR Lyrae and Cepheids with the Radial Velocity Spectrometer (RVS) on boardGaiawere also processed through the pipeline. Methods.The SOS Cep&RRL validation of DR3 candidate RR Lyrae stars relies on diagnostics tools that include the period versusG-amplitude diagram and the period…

Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in the Galaxy, and a well-defined sample of 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars and star clusters, extending across a very wide range of abundances and ages. This provides a legacy data set of intrinsic value, and equally a large wide-ranging dataset that is of value for the homogenisation of other and future stellar surveys and Gaia's astrophysical parameters. Aims. This article provides an overview of the survey methodology, the scientific aims, and the implementation, including a description of the data processing for the GIRAFFE spectra. A companion paper introduces the survey results. Methods. Gaia-ESO aspires to quantify both random and systematic contributions to measurement uncertainties. Thus, all available spectroscopic analysis techniques are utilised, each spectrum being…

Context. Three-dimensional (3D) maps of the extinction density in the Milky Way can be built through the inversion of large catalogues of distance-extinction pairs for individual target stars. Considerable progress is currently achieved in this field through the Gaia mission. Available catalogues are based on various types of photometric or spectrophotometric information and on different techniques of extinction estimations. Aims. The spatial resolution of the maps that can be achieved increases with the spatial density of the target stars, and, consequently, with the combination of input catalogues containing different target lists. However, this requires careful inter-calibration of the catalogues. Our aim is to develop methods of inter-comparison and inter-calibration of two different extinction catalogues. Methods. The catalogue we used as reference for inter-calibration is a spectrophotometric catalogue. It provides a more accurate extinction than a purely photometric catalogue. In order to reduce the dimension of the problem, a principal component analysis was performed in ( G…

Context. Proxima Centauri is the closest star to the Sun. This small, low-mass, mid M dwarf is known to host an Earth-mass exoplanet with an orbital period of 11.2 days within the habitable zone, as well as a long-period planet candidate with an orbital period of close to 5 yr. Aims. We report on the analysis of a large set of observations taken with the ESPRESSO spectrograph at the VLT aimed at a thorough evaluation of the presence of a third low-mass planetary companion, which started emerging during a previous campaign. Methods. Radial velocities (RVs) were calculated using both a cross-correlation function (CCF) and a template matching approach. The RV analysis includes a component to model Proxima’s activity using a Gaussian process (GP). We use the CCF’s full width at half maximum to help constrain the GP, and we study other simultaneous observables as activity indicators in order to assess the nature of any potential RV signals. Results. We detect a signal at 5.12 ± 0.04 days with a semi-amplitude of 39 ± 7 cm s −1 . The analysis of subsets of the ESPRESSO data, the activity…

We use integral field spectroscopy from the PHANGS–MUSE survey, which resolves the ionised interstellar medium structure at ∼50 pc resolution in 19 nearby spiral galaxies, to study the origin of the diffuse ionised gas (DIG). We examine the physical conditions of the diffuse gas by first removing morphologically defined H II regions and then binning the low-surface-brightness areas to achieve significant detections of the key nebular lines in the DIG. A simple model for the leakage and propagation of ionising radiation from H II regions is able to reproduce the observed distribution of H α in the DIG. This model infers a typical mean free path for the ionising radiation of 1.9 kpc for photons propagating within the disc plane. Leaking radiation from H II regions also explains the observed decrease in line ratios of low-ionisation species ([S II ]/H α , [N II ]/H α , and [O I ]/H α ) with increasing H α surface brightness (Σ H α ). Emission from hot low-mass evolved stars, however, is required to explain: (1) the enhanced low-ionisation line ratios observed in the central regions of…

Context.The improvements in the precision of the published data inGaiaEDR3 with respect toGaiaDR2, particularly for parallaxes and proper motions, offer the opportunity to increase the number of known open clusters in the Milky Way by detecting farther and fainter objects that have thus far gone unnoticed. Aims.Our aim is to continue to complete the open cluster census in the Milky Way with the detection of new stellar groups in the Galactic disc. We useGaiaEDR3 up to magnitudeG= 18 mag, increasing the magnitude limit and therefore the search volume explored in one unit with respect to our previous studies. Methods.We used theOCfindermethod to search for new open clusters inGaiaEDR3 using a big data environment. As a first step,OCfinderidentified stellar statistical overdensities in five-dimensional astrometric space (position, parallax, and proper motions) using theDBSCANclustering algorithm. Then, these overdensities were classified into random statistical overdensities or real physical open clusters using a deep artificial neural network trained on…

Context. In November 2019, eROSITA on board of the Spektrum-Roentgen-Gamma (SRG) observatory started to map the entire sky in X-rays. After the four-year survey program, it will reach a flux limit that is about 25 times deeper than ROSAT. During the SRG performance verification phase, eROSITA observed a contiguous 140 deg 2 area of the sky down to the final depth of the eROSITA all-sky survey (eROSITA Final Equatorial-Depth Survey; eFEDS), with the goal of obtaining a census of the X-ray emitting populations (stars, compact objects, galaxies, clusters of galaxies, and active galactic nuclei) that will be discovered over the entire sky. Aims. This paper presents the identification of the counterparts to the point sources detected in eFEDS in the main and hard samples and their multi-wavelength properties, including redshift. Methods. To identifyy the counterparts, we combined the results from two independent methods ( NWAY and ASTROMATCH ), trained on the multi-wavelength properties of a sample of 23k XMM-Newton sources detected in the DESI Legacy Imaging Survey DR8. Then…

Context. The star cluster R136 inside the Large Magellanic Cloud hosts a rich population of massive stars, including the most massive stars known. The strong stellar winds of these very luminous stars impact their evolution and the surrounding environment. We currently lack detailed knowledge of the wind structure that is needed to quantify this impact. Aims. Our goal is to observationally constrain the stellar and wind properties of the massive stars in R136, in particular the wind-structure parameters related to wind clumping. Methods. We simultaneously analyse optical and ultraviolet spectroscopy of 53 O-type and three WNh-stars using the F astwind model atmosphere code and a genetic algorithm. The models account for optically thick clumps and effects related to porosity and velocity-porosity, as well as a non-void interclump medium. Results. We obtain stellar parameters, surface abundances, mass-loss rates, terminal velocities, and clumping characteristics and compare them to theoretical predictions and evolutionary models. The clumping properties include the density of the…

We present the second data release of the MUSEHubbleUltra-Deep Field surveys, which includes the deepest spectroscopic survey ever performed. The MUSE data, with their 3D content, amazing depth, wide spectral range, and excellent spatial and medium spectral resolution, are rich in information. Their location in theHubbleultra-deep field area, which benefits from an exquisite collection of ancillary panchromatic information, is a major asset. This update of the first release incorporates a new 141-h adaptive-optics-assisted MUSE eXtremely Deep Field (MXDF; 1 arcmin diameter field of view) in addition to the reprocessed 10-h mosaic (3 × 3 arcmin2) and the single 31-h deep field (1 × 1 arcmin2). All three data sets were processed and analyzed homogeneously using advanced data reduction and analysis methods. The 3σpoint-source flux limit of an unresolved emission line reaches 3.1 × 10−19and 6.3 × 10−20 erg s−1 cm−2at 10- and 141-h depths, respectively. We have securely identified and measured the redshift of 2221 sources, an increase of 41% compared to the first release. With the…

Context. Gaia -CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia -CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International…

We combine results from deep ALMA observations of massive (M* > 1010 M⊙) galaxies at different redshifts to show that the column density of their interstellar medium (ISM) rapidly increases toward early cosmic epochs. Our analysis includes objects from the ASPECS and ALPINE large programs, as well as individual observations ofz ∼ 6 quasar hosts. When accounting for non-detections and correcting for selection effects, we find that the median surface density of the ISM of the massive galaxy population evolves as ∼(1 + z)3.3. This means that the ISM column density toward the nucleus of az > 3 galaxy is typically > 100 times larger than locally, and it may reach values as high as Compton-thick atz ≳ 6. Remarkably, the median ISM column density is on the same order of what is measured from X-ray observations of large active galactic nucleus (AGN) samples already atz ≳ 2. We have developed a simple analytic model for the spatial distribution of ISM clouds within galaxies, and estimate the total covering factor toward active nuclei when obscuration by ISM clouds on the host scale is added…

The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that…

Context. The classification of the minor bodies of the Solar System based on observables has been continuously developed and iterated over the past 40 yr. While prior iterations followed either the availability of large observational campaigns or new instrumental capabilities opening new observational dimensions, we see the opportunity to improve primarily upon the established methodology. Aims. We developed an iteration of the asteroid taxonomy which allows the classification of partial and complete observations (i.e. visible, near-infrared, and visible-near-infrared spectrometry) and which reintroduces the visual albedo into the classification observables. The resulting class assignments are given probabilistically, enabling the uncertainty of a classification to be quantified. Methods. We built the taxonomy based on 2983 observations of 2125 individual asteroids, representing an almost tenfold increase of sample size compared with the previous taxonomy. The asteroid classes are identified in a lower-dimensional representation of the observations using a mixture of common factor…

Context. GSN 069 is the first galactic nucleus where quasi-periodic eruptions (QPEs) have been identified in December 2018. These are high-amplitude, soft X-ray bursts recurring every ∼9 h, lasting ∼1 h, and during which the X-ray count rate increases by up to two orders of magnitude with respect to an otherwise stable quiescent level. The X-ray spectral properties and the long-term evolution of GSN 069 in the first few years since its first X-ray detection in 2010 are consistent with a long-lived tidal disruption event (TDE). Aims. We aim to derive the properties of QPEs and of the long-term X-ray evolution in GSN 069 over the past 12 yr. Methods. We analyse timing and spectral X-ray data from 11 XMM-Newton, one Chandra, and 34 Swift observations of GSN 069 on timescales ranging from minutes to years. Results. QPEs in GSN 069 are a transient phenomenon with a lifetime of ≳1.05 yr. The QPE intensity and recurrence time oscillate and allow for alternating strong-weak QPEs and long-short recurrence times to be defined. In observations with QPEs, the quiescent level exhibits a…

Context. In the past few years, there has been a rise in the detection of streamers, asymmetric flows of material directed toward the protostellar disk with material from outside a star’s natal core. It is unclear how they affect the process of mass accretion, in particular beyond the Class 0 phase. Aims. We investigate the gas kinematics around Per-emb-50, a Class I source in the crowded star-forming region NGC 1333. Our goal is to study how the mass infall proceeds from envelope to disk scales in this source. Methods. We use new NOEMA 1.3 mm observations, including C 18 O, H 2 CO, and SO, in the context of the PRODIGE MPG – IRAM program, to probe the core and envelope structures toward Per-emb-50. Results. We discover a streamer delivering material toward Per-emb-50 in H 2 CO and C 18 O emission. The streamer’s emission can be well described by the analytic solutions for an infalling parcel of gas along a streamline with conserved angular momentum, both in the image plane and along the line-of-sight velocities. The streamer has a mean infall rate of 1.3 × 10 −6 M ⊙ yr− 1 , five to…

Due to tidal interactions in the Earth-Moon system, the spin of the Earth slows down and the Moon drifts away. This recession of the Moon can now be measured with great precision, but it was noticed more than fifty years ago that simple tidal models extrapolated back in time lead to an age of the Moon that is largely incompatible with the geochronological and geochemical evidence. In order to evade this problem, more elaborate models have been proposed, taking into account the oceanic tidal dissipation. However, these models have not been able to fit both the estimated lunar age and the present rate of lunar recession simultaneously. In the present work, we present a physical model that reconciles these two constraints and yields a unique solution for the tidal history. This solution fits the available geological proxies for the history of the Earth-Moon system well and it consolidates the cyclostratigraphic method. Our work extends the lineage of earlier works on the analytical treatment of fluid tides on varying bounded surfaces that is further coupled with solid tidal…

We report on the polarized light curves of the Galactic Center supermassive black hole Sagittarius A * , obtained at millimeter wavelength with the Atacama Large Millimeter/submillimeter Array (ALMA). The observations took place as a part of the Event Horizon Telescope campaign. We compare the observations taken during the low variability source state on 2017 Apr. 6 and 7 with those taken immediately after the X-ray flare on 2017 Apr. 11. For the latter case, we observe rotation of the electric vector position angle with a timescale of ∼70 min. We interpret this rotation as a signature of the equatorial clockwise orbital motion of a hot spot embedded in a magnetic field dominated by a dynamically important vertical component, observed at a low inclination ∼20°. The hot spot radiates strongly polarized synchrotron emission, briefly dominating the linear polarization measured by ALMA in the unresolved source. Our simple emission model captures the overall features of the polarized light curves remarkably well. Assuming a Keplerian orbit, we find the hot spot orbital radius to be ∼5…

Context. The eROSITA Final Equatorial Depth Survey (eFEDS), observed with eROSITA ahead of its planned 4-yr all-sky survey, is the largest contiguous-field X-ray survey at present. It yielded a large sample of X-ray sources with very rich multiband photometric and spectroscopic coverage. Aims. We present here the eFEDS active galactic nuclei (AGN) catalog and the eROSITA X-ray spectral properties of the eFEDS sources. Methods. Using a Bayesian method, we performed a systematic X-ray spectral analysis for all the eFEDS sources. We adopted multiple spectral models, including single-component power-law or hot-plasma models and double-component models of a power law plus soft excess. We investigated the capacity of eROSITA X-ray spectra for constraining AGN spectral shapes through a detailed analysis of the posterior parameter probability distribution functions. Hierarchical Bayesian modeling was used to recover the spectral parameter distribution of the sample. The source fluxes and luminosities were measured from the posterior of the spectral fitting. Results. The eFEDS AGN catalog…

Context. The CARMENES instrument, installed at the 3.5 m telescope of the Calar Alto Observatory in Almería, Spain, was conceived to deliver high-accuracy radial velocity (RV) measurements with long-term stability to search for temperate rocky planets around a sample of nearby cool stars. Moreover, the broad wavelength coverage was designed to provide a range of stellar activity indicators to assess the nature of potential RV signals and to provide valuable spectral information to help characterise the stellar targets. Aims. We describe the CARMENES guaranteed time observations (GTO), spanning from 2016 to 2020, during which 19 633 spectra for a sample of 362 targets were collected. We present the CARMENES Data Release 1 (DR1), which makes public all observations obtained during the GTO of the CARMENES survey. Methods. The CARMENES survey target selection was aimed at minimising biases, and about 70% of all known M dwarfs within 10 pc and accessible from Calar Alto were included. The data were pipeline-processed, and high-level data products, including 18 642 precise RVs for 345…

Context. High-frequency very-long-baseline interferometry (VLBI) observations can now resolve the event-horizon-scale emission from sources in the immediate vicinity of nearby supermassive black holes. Future space-VLBI observations will access highly lensed features of black hole images – photon rings – that will provide particularly sharp probes of strong-field gravity. Aims. Focusing on the particular case of the supermassive black hole M 87*, our goal is to explore a wide variety of accretion flows onto a Kerr black hole and to understand their corresponding images and visibilities. We are particularly interested in the visibility on baselines to space, which encodes the photon ring shape and whose measurement could provide a stringent test of the Kerr hypothesis. Methods. We developed a fully analytical model of stationary, axisymmetric accretion flows with a variable disk thickness and a matter four-velocity that can smoothly interpolate between purely azimuthal rotation and purely radial infall. To determine the observational appearance of such flows, we numerically…

The Gaia Galactic survey mission is designed and optimized to obtain astrometry, photometry, and spectroscopy of nearly two billion stars in our Galaxy. Yet as an all-sky multi-epoch survey, Gaia also observes several million extragalactic objects down to a magnitude of G ∼ 21 mag. Due to the nature of the Gaia onboard-selection algorithms, these are mostly point-source-like objects. Using data provided by the satellite, we have identified quasar and galaxy candidates via supervised machine learning methods, and estimate their redshifts using the low resolution BP / RP spectra. We further characterise the surface brightness profiles of host galaxies of quasars and of galaxies from pre-defined input lists. Here we give an overview of the processing of extragalactic objects, describe the data products in Gaia DR3, and analyse their properties. Two integrated tables contain the main results for a high completeness, but low purity (50−70%), set of 6.6 million candidate quasars and 4.8 million candidate galaxies. We provide queries that select purer sub-samples of these containing 1.9…

Gaia Data Release 3 provides novel flux-calibrated low-resolution spectrophotometry for ≃220 million sources in the wavelength range 330 nm ≤ λ ≤ 1050 nm (XP spectra). Synthetic photometry directly tied to a flux in physical units can be obtained from these spectra for any passband fully enclosed in this wavelength range. We describe how synthetic photometry can be obtained from XP spectra, illustrating the performance that can be achieved under a range of different conditions – for example passband width and wavelength range – as well as the limits and the problems affecting it. Existing top-quality photometry can be reproduced within a few per cent over a wide range of magnitudes and colour, for wide and medium bands, and with up to millimag accuracy when synthetic photometry is standardised with respect to these external sources. Some examples of potential scientific application are presented, including the detection of multiple populations in globular clusters, the estimation of metallicity extended to the very metal-poor regime, and the classification of white dwarfs. A…

Context. Relativistic electrons and magnetic fields permeate the intra-cluster medium (ICM) and manifest themselves as diffuse sources of synchrotron emission observable at radio wavelengths, namely radio halos and radio relics. Although there is broad consensus that the formation of these sources is connected to turbulence and shocks in the ICM, the details of the required particle acceleration, the strength and morphology of the magnetic field in the cluster volume, and the influence of other sources of high-energy particles are poorly known. Aims. Sufficiently large samples of radio halos and relics, which would allow us to examine the variation among the source population and pinpoint their commonalities and differences, are still missing. At present, due to the physical properties of the sources and the capabilities of existing facilities, large numbers of these sources are easiest to detect at low radio frequencies, where they shine brightly. Methods. We examined the low-frequency radio emission from all 309 clusters in the second catalog of Planck Sunyaev Zel’dovich detected…

Context. Cepheids are pulsating stars that play a crucial role in several astrophysical contexts. Among the different types, the Classical Cepheids are fundamental tools for the calibration of the extragalactic distance ladder. They are also powerful stellar population tracers in the context of Galactic studies. The Gaia Third Data Release (DR3) publishes improved data on Cepheids collected during the initial 34 months of operations. Aims. We present the Gaia DR3 catalogue of Cepheids of all types, obtained through the analysis carried out with the Specific Object Study (SOS) Cep&RRL pipeline. Methods. We discuss the procedures adopted to clean the Cepheid sample from spurious objects, to validate the results, and to re-classify sources with an incorrect outcome from the SOS Cep&RRL pipeline. Results. The Gaia DR3 includes multi-band time-series photometry and characterisation by the SOS Cep&RRL pipeline for a sample of 15 006 Cepheids of all types. The sample includes 4663, 4616, 321, and 185 pulsators, distributed in the Large and Small Magellanic Cloud, Messier 31, and Messier…

We used the COSMOS2020 catalog to measure the stellar-to-halo mass relation (SHMR) divided by central and satellite galaxies from z = 0.2 to z = 5.5. Starting from accurate photometric redshifts, we measured the near-infrared selected two-point angular correlation and stellar mass functions in ten redshift bins. We used a phenomenological model that parametrizes the stellar-to-halo mass relation for central galaxies and the number of galaxies inside each halo to describe our observations. This model qualitatively reproduces our measurements and their dependence on the stellar mass threshold. Surprisingly, the mean halo occupation distribution only shows a mild evolution with redshift suggesting that galaxies occupy halos similarly throughout cosmic time. At each redshift, we measured the ratio of stellar mass to halo mass, M * / M h , which shows the characteristic strong dependence of halo mass with a peak at M h peak ∼ 2 × 10 12 M ⊙ . For the first time, using a joint modeling of clustering and abundances, we measured the evolution of M h peak from z = 0.2 to z = 5.5. M h peak…

We set out to determine stellar labels from low-resolution survey spectra of hot stars, specifically OBA stars with T eff ≳ 7500 K. This fills a gap in the scientific analysis of large spectroscopic stellar surveys such as LAMOST, which offers spectra for millions of stars at R ~ 1800 and covers 3800 Å ≤ λ ≤ 9000 Å. We first explore the theoretical information content of such spectra to determine stellar labels via the Cramér-Rao bound. We show that in the limit of perfect model spectra and observed spectra with signal-to-noise ratio ~50–100, precise estimates are possible for a wide range of stellar labels: not only the effective temperature, T eff , surface gravity, log g , and projected rotation velocity, v sin i , but also the micro-turbulence velocity, v mic , helium abundance, N He / N tot , and the elemental abundances [C/H], [N/H], [O/H], [Si/H], [S/H], and [Fe/H]. Our analysis illustrates that the temperature regime of T eff ~ 9500 K is challenging as the dominant Balmer and Paschen line strengths vary little with T eff . We implement the simultaneous fitting of these 11…

Aims. Combining 66 ultraviolet (UV) spectra and ancillary data from the recent Low-Redshift Lyman Continuum Survey (LzLCS) and 23 LyC observations by earlier studies, we form a statistical sample of star-forming galaxies at z ∼ 0.2 − 0.4 with which we study the role of cold interstellar medium (ISM) gas in the leakage of ionizing radiation. We also aim to establish empirical relations between the H I neutral and low-ionization state (LIS) absorption lines with different galaxy properties. Methods. We first constrain the massive star content (stellar ages and metallicities) and UV attenuation by fitting the stellar continuum with a combination of simple stellar population models. The models, together with accurate LyC flux measurements, allow us to determine the absolute LyC photon escape fraction for each galaxy ( f esc abs ). We then measure the equivalent widths and residual fluxes of multiple H I and LIS lines, and the geometrical covering fraction of the UV emission, adopting the picket-fence model. Results. The LyC escape fraction spans a wide range, with a median f esc abs…

Context. The third Gaia Data Release covers 34 months of data and includes the second Gaia catalogue of long-period variables (LPVs), with G variability amplitudes larger than 0.1 mag (5–95% quantile range). Aims. The paper describes the production and content of the second Gaia catalogue of LPVs and the methods we used to compute the published variability parameters and identify C-star candidates. Methods. We applied various filtering criteria to minimise contamination from variable star types other than LPVs. The period and amplitude of the detected variability were derived from model fits to the G -band light curve wherever possible. C stars were identified using their molecular signature in the low-resolution RP spectra. Results. The catalogue contains 1 720 558 LPV candidates, including 392 240 stars with published periods (ranging from 35 to ∼1000 days) and 546 468 stars classified as C-star candidates. Comparison with literature data (OGLE and ASAS-SN) leads to an estimated completeness of 80%. The recovery rate is about 90% for the most regular stars (typically miras) and…

We report the detection of fulvenallene ( c -C 5 H 4 CCH 2 ) in the direction of TMC-1 with the QUIJOTE 1 line survey. Thirty rotational transitions with K a = 0,1,2,3 and J = 9−15 were detected. The best rotational temperature fitting of the data is 9 K and a derived column density is (2.7 ± 0.3) × 10 12 cm −2 , which is only a factor of 4.4 below that of its potential precursor cyclopentadiene ( c -C 5 H 6 ), and 1.4–1.9 times higher than that of the ethynyl derivatives of cyclopentadiene. We searched for fulvene ( c -C 5 H 4 CH 2 ), a CH 2 derivative of cyclopentadiene, for which we derive a 3 σ upper limit to its column density of (3.5 ± 0.5) × 10 12 cm −2 . Upper limits were also obtained for toluene (C 6 H 5 CH 3 ) and styrene (C 6 H 5 C 2 H 3 ), the methyl and vinyl derivatives of benzene. Fulvenallene and ethynyl cyclopentadiene are likely formed in the reaction between cyclopentadiene ( c -C 5 H 6 ) and the ehtynyl radical (CCH). However, the bottom-up gas-phase synthesis of cycles in TMC-1 underestimates the abundance of cyclopentadiene by two orders of magnitude, which…

Context.While Jupiter’s massive gas envelope consists mainly of hydrogen and helium, the key to understanding Jupiter’s formation and evolution lies in the distribution of the remaining (heavy) elements. Before the Juno mission, the lack of high-precision gravity harmonics precluded the use of statistical analyses in a robust determination of the heavy-element distribution in Jupiter’s envelope. Aims.In this paper, we assemble the most comprehensive and diverse collection of Jupiter interior models to date and use it to study the distribution of heavy elements in the planet’s envelope. Methods.We apply a Bayesian statistical approach to our interior model calculations, reproducing the Juno gravitational and atmospheric measurements and constraints from the deep zonal flows. Results.Our results show that the gravity constraints lead to a deep entropy of Jupiter corresponding to a 1 bar temperature that is 515 K higher than traditionally assumed. We also find that uncertainties in the equation of state are crucial when determining the amount of heavy elements in Jupiter’s interior.…

Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95–2.02 µm range, to a 5 σ point-source median depth of 24.4 AB mag. This unique photometric dataset will find wide use beyond Euclid’s core science. In this paper, we present accurate computations of the Euclid Y E , J E , and H E passbands used by the Near-Infrared Spectrometer and Photometer (NISP), and the associated photometric system. We pay particular attention to passband variations in the field of view, accounting for, among other factors, spatially variable filter transmission and variations in the angle of incidence on the filter substrate using optical ray tracing. The response curves’ cut-on and cut-off wavelengths – and their variation in the field of view – are determined with ~0.8 nm accuracy, essential for the photometric redshift accuracy required by Euclid. After computing the photometric zero points in the AB mag system, we present linear transformations from and to common ground-based near-infrared photometric systems, for normal stars, red and brown dwarfs, and galaxies…

Context. Extended and delayed emission around distant TeV sources induced by the effects of propagation of γ ray s through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). Aims. We search for delayed GeV emission from the hard-spectrum TeV γ -ray emitting blazar 1ES 0229+200, with the goal of detecting or constraining the IGMF-dependent secondary flux generated during the propagation of TeV γ rays through the intergalactic medium. Methods. We analysed the most recent MAGIC observations over a 5 year time span, and complemented them with historic data of the H.E.S.S. and VERITAS telescopes, along with a 12-year-long exposure of the Fermi /LAT telescope. We used them to trace source evolution in the GeV–TeV band over a decade and a half. We used Monte Carlo simulations to predict the delayed secondary γ -ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compared these predictions for various assumed IGMF strengths to all available measurements of the γ -ray flux evolution. Results. We find…

Context. Estimating the distances to asymptotic giant branch (AGB) stars using optical measurements of their parallaxes is not straightforward because of the large uncertainties introduced by their dusty envelopes, their large angular sizes, and their surface brightness variability. Aims. This paper aims to assess the reliability of the distances derived with Gaia DR3 parallaxes for AGB stars, and provide a new distance catalogue for a sample of ∼200 nearby AGB stars. Methods. We compared the parallaxes from Gaia DR3 with parallaxes measured with maser observations with very long baseline interferometry (VLBI) to determine a statistical correction factor for the DR3 parallaxes using a sub-sample of 33 maser-emitting oxygen-rich nearby AGB stars. We then calculated the distances of a total of ∼200 AGB stars in the DEATHSTAR project using a Bayesian statistical approach on the corrected DR3 parallaxes and a prior based on the previously determined Galactic distribution of AGB stars. We performed radiative transfer modelling of the stellar and dust emission to determine the luminosity…

We conduct a pseudo- C ℓ analysis of the tomographic cross-correlation between 1000 deg 2 of weak-lensing data from the Kilo-Degree Survey (KiDS-1000) and the thermal Sunyaev–Zeldovich (tSZ) effect measured by Planck and the Atacama Cosmology Telescope (ACT). Using HM X , a halo-model-based approach that consistently models the gas, star, and dark matter components, we are able to derive constraints on both cosmology and baryon feedback for the first time from these data, marginalising over redshift uncertainties, intrinsic alignment of galaxies, and contamination by the cosmic infrared background (CIB). We find our results to be insensitive to the CIB, while intrinsic alignment provides a small but significant contribution to the lensing–tSZ cross-correlation. The cosmological constraints are consistent with those of other low-redshift probes and prefer strong baryon feedback. The inferred amplitude of the lensing–tSZ cross-correlation signal, which scales as σ 8 (Ω m /0.3) 0.2 , is low by ∼2 σ compared to the primary cosmic microwave background constraints by Planck . The…

Context.Quasi-periodic X-ray eruptions (QPEs) are a recently discovered phenomenon, the nature of which remains unclear. Based on their discovery in active galactic nuclei (AGNs), explanations related to an AGN accretion disk or potentially a stellar tidal disruption event (TDE) have been put forward. Alternatives, including highly unequal mass compact object binaries, have also been proposed to explain their properties. Aims.We perform a systematic study of the five known QPE host galaxies with the aim of providing new insights as to their nature. Methods.We analysed new and archival medium resolution optical spectroscopy of the QPE hosts. We measured emission (and absorption) line fluxes, their ratios, and equivalent widths (EWs) to locate the QPE hosts on diagnostic diagrams. We also measured the velocity dispersion of the stellar absorption lines to estimate their black hole masses. Results.All QPE host galaxies show emission lines in their optical spectra. Based on their ratios and EWs, we find evidence for the presence of an AGN in all sources, including those previously…

The Near-Inrared Spectrograph (NIRSpec) on theJames WebbSpace Telescope (JWST) is a very versatile instrument, offering mul-tiobject and integral field spectroscopy with varying spectral resolution (~30 to ~3000) over a wide wavelength range from 0.6 to 5.3 micron, enabling scientists to study many science themes ranging from the first galaxies to bodies in our own Solar System. In addition to its integral field unit and support for multiobject spectroscopy, NIRSpec features several fixed slits and a wide aperture specifically designed to enable high precision time-series and transit as well as eclipse observations of exoplanets. In this paper we present its capabilities regarding time-series observations, in general, and transit and eclipse spectroscopy of exoplanets in particular. Due to JWST’s large collecting area and NIRSpec’s excellent throughput, spectral coverage, and detector performance, this mode will allow scientists to characterize the atmosphere of exoplanets with unprecedented sensitivity.

Context. The spatial distribution of elemental abundances and their time evolution are among the major constraints to disentangling the scenarios of formation and evolution of the Galaxy. Aims. In this paper we used the sample of open clusters available in the final release of the Gaia -ESO survey to trace the Galactic radial abundance and abundance-to-iron ratio gradients, and their time evolution. Methods. We selected member stars in 62 open clusters, with ages from 0.1 to about 7 Gyr, located in the Galactic thin disc at galactocentric radii ( R GC ) from about 6 to 21 kpc. We analysed the shape of the resulting [Fe/H] gradient, the average gradients [El/H] and [El/Fe] combining elements belonging to four different nucleosynthesis channels, and their individual abundance and abundance ratio gradients. We also investigated the time evolution of the gradients dividing open clusters in three age bins. Results. The [Fe/H] gradient has a slope of −0.054 dex kpc −1 . It can be better approximated with a two-slope shape, steeper for R GC ≤ 11.2 kpc and flatter in the outer regions. We…

Context.As part of the thirdGaiaData Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters usingGaiadata. This is the third in a series of three papers describing the work done within CU8 for this release. Aims.For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce forGaiaDR3. We further advise how to use these data products and highlight some limitations. Methods.The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier…

Context. Planets form during the first few Myr of the evolution of the star-disk system, possibly before the end of the embedded phase. The properties of very young disks and their subsequent evolution reflect the presence and properties of their planetary content. Aims. We present a study of the Class II/F disk population in L1688, the densest and youngest region of star formation in Ophiuchus. We also compare it to other well-known nearby regions of different ages, namely Lupus, Chamaeleon I, Corona Australis, Taurus and Upper Scorpius. Methods. We selected our L1688 sample using a combination of criteria (available ALMA data, Gaia membership, and optical and near-IR spectroscopy) to determine the stellar and disk properties, specifically stellar mass (M⋆), average population age, mass accretion rate (Ṁacc) and disk dust mass (Ṁdust). We applied the same procedure in a consistent manner to the other regions. Results. In L1688 the relations between Ṁacc and M⋆, Mdust and M⋆, and Ṁacc and Mdust have a roughly linear trend with slopes 1.8–1.9 for the first two relations and ~1 for…

Aims.HD 206893 is a nearby debris disk star that hosts a previously identified brown dwarf companion with an orbital separation of ∼10 au. Long-term precise radial velocity (RV) monitoring, as well as anomalies in the system proper motion, has suggested the presence of an additional, inner companion in the system. Methods.Using information from ongoing precision RV measurements with the HARPS spectrograph, as well asGaiahost star astrometry, we have undertaken a multi-epoch search for the purported additional planet using the VLTI/GRAVITY instrument. Results.We report a high-significance detection over three epochs of the companion HD 206893c, which shows clear evidence for Keplerian orbital motion. Our astrometry with ∼50−100 μarcsec precision afforded by GRAVITY allows us to derive a dynamical mass of 12.7$ ^{+1.2}_{-1.0} $MJupand an orbital separation of 3.53$ ^{+0.08}_{-0.06} $ au for HD 206893c. Our fits to the orbits of both companions in the system use bothGaiaastrometry and RVs to also provide a precise dynamical estimate of the previously uncertain mass of the B component,…

Interpreting and modelling astronomical catalogues requires an understanding of the catalogues’ completeness or selection function: what properties determine an object’s probability of being including in the catalogue? Here we set out to empirically quantify the completeness of the overall catalogue of Gaia ’s third data release (DR3). This task is not straightforward because Gaia is the all-sky optical survey with the highest angular resolution to date and no consistent ground truth exists to allow direct comparisons. However, well-characterised deeper imaging enables an empirical assessment of Gaia ’s G -band completeness across parts of the sky. On this basis, we devised a simple analytical completeness model of Gaia as a function of the observed G magnitude and position over the sky, which accounts for both the effects of crowding and the complex Gaia scanning law. Our model only depends on a single quantity: the median magnitude M 10 in a patch of the sky of catalogued sources with astrometric_matched_transits ≤10. We note that M 10 reflects elementary completeness decisions in…

Context. The quest to detect dormant stellar-mass black holes (BHs) in massive binaries (i.e. OB+BH systems) is challenging; only a few candidates have been claimed to date, all of which must still be confirmed. Aims. To search for these rare objects, we study 32 Galactic O-type stars that were reported as single-lined spectroscopic binaries (SB1s) in the literature. In our sample we include Cyg X-1, which is known to host an accreting stellar-mass BH, and HD 74194, a supergiant fast X-ray transient, in order to validate our methodology. The final goal is to characterise the nature of the unseen companions to determine if they are main-sequence (MS) stars, stripped helium stars, triples, or compact objects such as neutron stars (NSs) or stellar-mass BHs. Methods. After measuring radial velocities and deriving orbital solutions for all the systems in our sample, we performed spectral disentangling to extract putative signatures of faint secondary companions from the composite spectra. We derived stellar parameters for the visible stars and estimated the mass ranges of the secondary…

We present new constraints on the frequency dependence of the cosmic birefringence angle from the Planck Data Release 4 polarization maps. An axion field coupled to electromagnetism predicts a nearly frequency-independent birefringence angle, βν = β, while Faraday rotation from local magnetic fields and Lorentz violating theories predict a cosmic birefringence angle that is proportional to the frequency, ν, to the power of some integer n, βν ∝ νn. In this work, we first sampled βν individually for each polarized HFI frequency band in addition to the 70 GHz channel from the LFI. We also constrained a power law formula for the birefringence angle, βν = β0(ν/ν0)n, with ν0 = 150 GHz. For a nearly full-sky measurement, fsky = 0.93, we find β0 = 0.26° ±0.11° (68% C.L.) and n = −0.45−0.82+0.61 when we ignore the intrinsic EB correlations of the polarized foreground emission, and β0 = 0.33° ±0.12° and n = −0.37−0.64+0.49 when we use a filamentary dust model for the foreground EB. Next, we used all the polarized Planck maps, including the 30 and 44 GHz frequency bands. These bands have a…

Aims.We present a cosmological analysis of abundances and stacked weak lensing profiles of galaxy clusters, exploiting the AMICO KiDS-DR3 catalogue. The sample consists of 3652 galaxy clusters with intrinsic richnessλ* ≥ 20, over an effective area of 377 deg2, in the redshift rangez ∈ [0.1, 0.6]. Methods.We quantified the purity and completeness of the sample through simulations. The statistical analysis has been performed by simultaneously modelling the co-moving number density of galaxy clusters and the scaling relation between the intrinsic richnesses and the cluster masses, assessed through stacked weak lensing profile modelling. The fluctuations of the matter background density, caused by super-survey modes, have been taken into account in the likelihood. Assuming a flat Λ cold dark matter (ΛCDM) model, we constrained Ωm,σ8,S8 ≡ σ8(Ωm/0.3)0.5, and the parameters of the mass-richness scaling relation. Results.We obtained Ωm = 0.24−0.04+0.03,σ8 = 0.86−0.07+0.07, andS8 = 0.78−0.04+0.04. The constraint onS8is consistent within 1σwith the results from WMAP and Planck. Furthermore,…

Polycyclic aromatic hydrocarbons (PAHs) are carbon-based molecules that are ubiquitous in a variety of astrophysical objects and environments. In this work we use JWST/MIRI MRS spectroscopy of three Seyferts to compare their nuclear PAH emission with that of star-forming (SF) regions. This study represents the first of its kind to use sub-arcsecond angular resolution data of local luminous Seyferts ( L bol > 10 44.46 erg s −1 ) with a wide wavelength coverage (4.9–28.1 μm). We present an analysis of their nuclear PAH properties by comparing the observed ratios with PAH diagnostic model grids derived from theoretical spectra. Our results show that a suite of PAH features is present in the innermost parts of luminous Seyfert galaxies (∼0.45″ at 12 μm; in the inner ∼142–245 pc). We find that the nuclear regions of active galactic nuclei (AGN) lie at different positions of the PAH diagnostic diagrams, whereas the SF regions are concentrated around the average values of SF galaxies. In particular, we find that the nuclear PAH emission mainly originates in neutral PAHs. In contrast, PAH…

The formation of merging binary black holes can occur through multiple astrophysical channels such as, e.g., isolated binary evolution and dynamical formation or, alternatively, have a primordial origin. Increasingly large gravitational-wave catalogs of binary black-hole mergers have allowed for the first model selection studies between different theoretical predictions to constrain some of their model uncertainties and branching ratios. In this work, we show how one could add an additional and independent constraint to model selection by using the stochastic gravitational-wave background. In contrast to model selection analyses that have discriminating power only up to the gravitational-wave detector horizons (currently at redshifts z ≲ 1 for LIGO–Virgo), the stochastic gravitational-wave background accounts for the redshift integration of all gravitational-wave signals in the Universe. As a working example, we consider the branching ratio results from a model selection study that includes potential contribution from astrophysical and primordial channels. We renormalize the…

Context. Gas phase Elemental abundances in molecular CloudS (GEMS) is an IRAM 30-m Large Program aimed at determining the elemental abundances of carbon (C), oxygen (O), nitrogen (N), and sulfur (S) in a selected set of prototypical star-forming filaments. In particular, the elemental abundance of S remains uncertain by several orders of magnitude, and its determination is one of the most challenging goals of this program. Aims. This paper aims to constrain the sulfur elemental abundance in Taurus, Perseus, and Orion A based on the GEMS molecular database. The selected regions are prototypes of low-mass, intermediate-mass, and high-mass star-forming regions, respectively, providing useful templates for the study of interstellar chemistry. Methods. We have carried out an extensive chemical modeling of the fractional abundances of CO, HCO + , HCN, HNC, CS, SO, H 2 S, OCS, and HCS + to determine the sulfur depletion toward the 244 positions in the GEMS database. These positions sample visual extinctions from A V ~ 3 mag to >50 mag, molecular hydrogen densities ranging from a few × 10 3…

Context. Observations at millimeter wavelengths of bright protoplanetary disks have shown the ubiquitous presence of structures such as rings and spirals in the continuum emission. The derivation of the underlying properties of the emitting material is nontrivial because of the complex radiative processes involved. Aims. In this paper we analyze new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) at high angular resolution corresponding to 5 – 8 au to determine the dust spatial distribution and grain properties in the ringed disk of HD 163296. Methods. We fit the spectral energy distribution as a function of the radius at five wavelengths from 0.9 to 9 mm, using a simple power law and a physical model based on an analytic description of radiative transfer that includes isothermal scattering. We considered eight dust populations and compared the models' performance using Bayesian evidence. Results. Our analysis shows that the moderately high optical depth ( τ >1) at λ ≤ 1.3 mm in the dust rings artificially lower…

Context. Hierarchical triple stars are ideal laboratories for studying the interplay between orbital dynamics and stellar evolution. Both mass loss from stellar winds and strong gravitational perturbations between the inner and outer orbit cooperate to destabilise triple systems. Aims. Our current understanding of the evolution of unstable triple systems is mainly built upon results from extensive binary-single scattering experiments. However, destabilised hierarchical triples cover a different region of phase space. Therefore, we aim to construct a comprehensive overview of the evolutionary pathways of destabilised triple-star systems. Methods. Starting from generic initial conditions, we evolved an extensive set of hierarchical triples using the code TRES, combining secular dynamics and stellar evolution. We detected those triples that destabilise due to stellar winds and/or gravitational perturbations. Their evolution was continued with a direct N -body integrator coupled to stellar evolution. Results. The majority of triples (54–69%) preserve their hierarchy throughout their…

Context. The third data release by the Gaia mission of the European Space Agency (DR3) is the first release to provide the community with a large sample of observations for more than 150 thousand Solar System objects, including asteroids and natural planetary satellites. The release contains astrometry (over 23 million epochs) and photometry, along with average reflectance spectra of 60518 asteroids and osculating elements. Aims. We present an overview of the procedures that have been implemented over several years of development and tests to process Solar System data at the level of accuracy that Gaia can reach. We illustrate the data properties and potential with some practical examples. Methods. In order to allow the users of Gaia DR3 to best exploit the data, we explain the assumptions and approaches followed in the implementation of the data processing pipeline for Solar System processing, and their effects in terms of data filtering, optimisation, and performances. We then test the data quality by analysing post-fit residuals to adjusted orbits, the capacity of detecting…

In light of substantial new discoveries of hot subdwarfs by ongoing spectroscopic surveys and the availability of the Gaia mission Early Data Release 3 (EDR3), we compiled new releases of two catalogues of hot subluminous stars: The data release 3 (DR3) catalogue of the known hot subdwarf stars contains 6616 unique sources and provides multi-band photometry, and astrometry from Gaia EDR3 as well as classifications based on spectroscopy and colours. This is an increase of 742 objects over the DR2 catalogue. This new catalogue provides atmospheric parameters for 3087 stars and radial velocities for 2791 stars from the literature. In addition, we have updated the Gaia Data Release 2 (DR2) catalogue of hot subluminous stars using the improved accuracy of the Gaia EDR3 data set together with updated quality and selection criteria to produce the Gaia EDR3 catalogue of 61 585 hot subluminous stars, representing an increase of 21 785 objects. The improvements in Gaia EDR3 astrometry and photometry compared to Gaia DR2 have enabled us to define more sophisticated selection functions. In…

We present an analysis of the quenching of star formation in galaxies, bulges, and disks throughout the bulk of cosmic history, from z = 2 − 0. We utilise observations from the Sloan Digital Sky Survey and the Mapping Nearby Galaxies at Apache Point Observatory survey at low redshifts. We complement these data with observations from the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey at high redshifts. Additionally, we compare the observations to detailed predictions from the LGalaxies semi-analytic model. To analyse the data, we developed a machine learning approach utilising a Random Forest classifier. We first demonstrate that this technique is extremely effective at extracting causal insight from highly complex and inter-correlated model data, before applying it to various observational surveys. Our primary observational results are as follows: at all redshifts studied in this work, we find bulge mass to be the most predictive parameter of quenching, out of the photometric parameter set (incorporating bulge mass, disk mass, total stellar mass, and B / T…

Context. Optical interferometry is at a key development stage. The Very Large Telescope Interferometer (VLTI) has established a stable, robust infrastructure for long-baseline interferometry that is usable by general astronomical observers. The present second-generation instruments offer a wide wavelength coverage and improved performance. Their sensitivity and measurement accuracy lead to data and images of high reliability. Aims. We have developed the Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) to access, for the first time, high resolution imaging in a wide spectral domain. Many front-line topics are explored with this new equipment, including: stellar activity and mass loss; planet formation and evolution in the gas and dust disks around young stars; and environment interaction and accretion processes around super massive black holes in active galactic nuclei. Methods. The instrument is a spectro-interferometric imager in the transmission windows called L , M , and N , from 2.8 to 13.0 microns, combining four optical beams from the VLTI’s unit or auxiliary…

Context. During its all-sky survey, the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Spectrum-Roentgen-Gamma (SRG) observatory has uncovered a growing number of X-ray transients associated with the nuclei of quiescent galaxies. Benefitting from its large field of view and excellent sensitivity, the eROSITA window into time-domain X-ray astrophysics yields a valuable sample of X-ray selected nuclear transients. Multi-wavelength follow-up enables us to gain new insights into understanding the nature and emission mechanism of these phenomena. Aims. We present the results of a detailed multi-wavelength analysis of an exceptional repeating X-ray nuclear transient, eRASSt J045650.3−203750 (hereafter J0456−20), uncovered by SRG/eROSITA in a quiescent galaxy at a redshift of z ∼ 0.077. We aim to understand the radiation mechanism at different luminosity states of J0456−20, and provide further evidence that similar accretion processes are at work for black hole accretion systems at different black hole mass scales. Methods. We describe our temporal…

Context. The stability of mass transfer is critical in determining pathways towards various kinds of compact binaries, such as compact main-sequence white-dwarf binaries, and transients, such as double white-dwarf mergers and luminous red novae. Despite its importance, very few systematic studies of the stability of mass transfer exist. Aims. We study the behaviour of mass-losing donor stars in binary systems in a systematic way. We focus on identifying and understanding the parameter space for stable mass transfer in low- and intermediate-mass binaries with post-main-sequence donor stars as well as the properties of ultimately unstable binary systems at the onset of the instabilities. Methods. We employed the 1D stellar evolution code MESA to simulate the mass-transfer evolution of 1404 binary systems with donor-star masses between 1 M ⊙ and 8 M ⊙ . We studied the behaviour of the binaries during mass transfer, without assuming that the donor star responds adiabatically to mass loss. We treated the accretor as a point mass, which we do not evolve, and assumed the mass transfer is…

Because mass loss is a fundamental phenomenon in massive stars, an interaction with circumstellar material (CSM) should be universal in core-collapse supernovae (SNe). Leaving aside the extreme CSM density, extent, or mass typically encountered in Type IIn SNe, we investigate the diverse long-term radiative signatures of an interaction between a Type II SN ejecta and CSM corresponding to mass-loss rates up to 10−3 M⊙ yr−1. Because these CSM are relatively tenuous and optically thin to electron scattering beyond a few stellar radii, radiation hydrodynamics is not essential and one may treat the interaction directly as an additional power source in the non-local thermodynamic equilibrium radiative transfer problem. The CSM accumulated since shock breakout forms a dense shell in the outer ejecta and leads to high-velocity absorption features in spectral lines, even for a negligible shock power. In addition to Balmer lines, such features may appear in Na I D and He I lines, among others. A stronger interaction strengthens the continuum flux (preferentially in the UV), quenches the…

Context. The iron abundance [Fe/H] in the atmosphere of FGK-type stars is crucial in stellar and galactic physics. The number of stars with a measured value of [Fe/H] is increasing considerably thanks to spectroscopic surveys. However, different methodologies, inputs, and assumptions used in spectral analyses lead to different precisions in [Fe/H] and possibly to systematic differences, which need to be evaluated. It is essential to understand the characteristics of each survey to fully exploit their potential, in particular if the surveys are combined to probe a larger galactic volume and to improve statistics. Aims. The purpose of this study is to compare [Fe/H] determinations from the largest spectroscopic surveys to other catalogues taken as reference. Offsets and dispersions of the residuals are examined, as are their trends with other parameters. The investigated surveys are the latest public releases of APOGEE, GALAH, RAVE, LAMOST, SEGUE, and the Gaia-ESO Survey. Methods. We use reference samples that provide independent determinations of [Fe/H], which are compared to those…

Context. Mergers and tidal interactions between massive galaxies and their dwarf satellites are a fundamental prediction of the Lambda-cold dark matter cosmology. These events are thought to provide important observational diagnostics of non-linear structure formation. Stellar streams in the Milky Way and Andromeda are spectacular evidence for ongoing satellite disruption. However, constructing a statistically meaningful sample of tidal streams beyond the Local Group has proven a daunting observational challenge, and the full potential for deepening our understanding of galaxy assembly using stellar streams has yet to be realised. Aims. Here we introduce the Stellar Stream Legacy Survey, a systematic imaging survey of tidal features associated with dwarf galaxy accretion around a sample of ∼3100 nearby galaxies within z ∼ 0.02, including about 940 Milky Way analogues. Methods. Our survey exploits public deep imaging data from the DESI Legacy Imaging Surveys, which reach surface brightness as faint as ∼29 mag arcsec −2 in the r band. As a proof of concept of our survey, we report the…

Baryonic feedback is expected to play a key role in regulating the star formation of low-mass galaxies by producing galaxy-scale winds associated with mass-loading factors of β ∼ 1 − 50. We test this prediction using a sample of 19 nearby systems with stellar masses of 107 < M⋆/M⊙ < 1010, mostly lying above the main sequence of star-forming galaxies. We used MUSE at VLT optical integral field spectroscopy to study the warm ionised gas kinematics of these galaxies via a detailed modelling of their Hα emission line. The ionised gas is characterised by irregular velocity fields, indicating the presence of non-circular motions of a few tens of km s−1 within galaxy discs, but with intrinsic velocity dispersion of 40 − 60 km s−1 that are only marginally larger than those measured in main-sequence galaxies. Galactic winds, defined as gas at velocities larger than the galaxy escape speed, encompass only a few percent of the observed fluxes. Mass outflow rates and loading factors are strongly dependent on M⋆, the star formation rate (SFR), SFR surface density, and specific SFR (sSFR). For M⋆…

Stable mass transfer from a massive post-main sequence (post-MS) donor is thought to be a short-lived event of thermal-timescale mass transfer (∼10 −3 M ⊙ yr −1 ) which within ≲10 4 yr strips the donor star of nearly its entire H-rich envelope, producing a hot, compact helium star. This long-standing picture is based on stellar models with rapidly expanding Hertzprung gap (HG) donor stars. Motivated by a finding that in low-metallicity binaries, post-MS mass transfer may instead be initiated by donors already at the core-helium burning (CHeB) stage, we used the MESA stellar-evolution code to compute grids of detailed massive binary models at three metallicities: those of the Sun, the Large Magellanic Cloud (LMC, Z Fe; LMC / Z Fe; ⊙ ≈ 0.36), and the Small Magellanic Cloud (SMC, Z Fe; SMC / Z Fe; ⊙ ≈ 0.2). Our grids span a wide range in orbital periods (∼3 to 5000 days) and initial primary masses (10 M ⊙ to 36 − 53 M ⊙ , depending on metallicity). We find that metallicity strongly influences the course and outcome of mass-transfer evolution. We identify two novel types of post-MS mass…

Quasi-periodic eruptions (QPEs) are recurrent X-ray bursts found in the nuclei of low-mass galaxies. Their trigger mechanism is still unknown, but recent models involving one or two stellar-mass companions around the central massive (≈105 − 106 M⊙) black hole have gathered significant attention. While these models have been compared only qualitatively with observations, the phenomenology of QPEs is developing at a fast pace, and has the potential to reveal new insights. Here we report two new observational results found in eRO-QPE1, the brightest QPE source discovered so far. First, the eruptions in eRO-QPE1 sometimes occur as single isolated bursts, and at others as chaotic mixtures of multiple overlapping bursts with very different amplitudes. Second, we confirm that QPEs peak at later times and are broader at lower energies than at higher energies, while we find for the first time that QPEs also start earlier at lower energies. Furthermore, eruptions appear to undergo a counterclockwise hysteresis cycle in a plane of hardness ratio versus total count rate. The first behavior has…

Quasi-periodic eruptions (QPEs), a new kind of X-ray burst with a recurrence time of several hours, have been detected from supermassive black holes (SMBHs) in galactic nuclei. Recently, the two QPEs discovered by the eROSITA showed asymmetric light curves with a fast rise and a slow decline. Current models cannot explain the observational characteristics of QPEs. In this work, we show that QPEs can be generated from the Roche lobe overflows at each periapsis passage of an evolved star orbiting a SMBH. The properties of the companion stars are constrained via analytic estimations. We find that hydrogen-deficient post-AGB stars are promising candidates for exhibiting this phenomenon. We used the Modules for Experiments in Stellar Astrophysics (MESA) stellar evolution code to construct the hydrogen-deficient stars that can fulfill the requirements, as obtained through analytical estimates, to produce the properties of QPEs, including the fast-rise and slow-decay light curves, periods, energetics, and rates. Furthermore, the extreme mass ratio ∼105 between the SMBH and the donor leads…

K2-141 b is a transiting, small (1.5 R⊕) ultra-short-period (USP) planet discovered by the Kepler space telescope orbiting a K-dwarf host star every 6.7 h. The planet's high surface temperature of more than 2000 K makes it an excellent target for thermal emission observations. Here we present 65 h of continuous photometric observations of K2-141 b collected with Spitzer's Infrared Array Camera (IRAC) Channel 2 at 4.5 μm spanning ten full orbits of the planet. We measured an infrared eclipse depth of ${f_{{{\rm{p}} \mathord{\left/ {\vphantom {{\rm{p}} {{{\rm{f}}_{\rm{*}}}}}} \right. \kern-\nulldelimiterspace} {{{\rm{f}}_{\rm{*}}}}}}} = 142.9_{ - 39.0}^{38.5}$ ppm and a peak to trough amplitude variation of $A = 120.6_{ - 43.0}^{42.3}$ ppm. The best fit model to the Spitzer data shows no significant thermal hotspot offset, in contrast to the previously observed offset for the well-studied USP planet 55 Cnc e. We also jointly analyzed the new Spitzer observations with the photometry collected by Kepler during two separate K2 campaigns. We modeled the planetary emission with a range of…

Context. Theories of the origins of life propose that early cell membranes were synthesised from amphiphilic molecules simpler than phospholipids, such as fatty alcohols. The discovery in the interstellar medium (ISM) of ethanolamine, the simplest phospholipid head group, raises the question whether simple amphiphilic molecules are also synthesised in space. Aims. We investigate whether precursors of fatty alcohols are present in the ISM. Methods. To do this, we have carried out a spectral survey at 7, 3, 2 and 1 mm towards the Giant Molecular Cloud G+0.693-0.027 located in the Galactic centre using the IRAM 30 m and Yebes 40 m telescopes. Results. Here, we report the detection in the ISM of the primary alcohol n -propanol (in both conformers Ga - n -C 3 H 7 OH and Aa - n -C 3 H 7 OH), a precursor of fatty alcohols. The derived column densities of n -propanol are (5.5 ± 0.4) × 10 13 cm −2 for the Ga conformer and (3.4 ± 0.3) × 10 13 cm −2 for the Aa conformer, which imply molecular abundances of (4.1 ± 0.3) × 10 −10 for Ga - n -C 3 H 7 OH and of (2.5 ± 0.2) × 10 −10 for Aa - n -C 3…

Utilizing spectroscopic observations taken for the VIMOS Ultra-Deep Survey (VUDS), new observations from Keck/DEIMOS, and publicly available observations of large samples of star-forming galaxies, we report here on the relationship between the star-formation rate (SFR) and the local environment ( δ gal ) of galaxies in the early universe (2 < z < 5). Unlike what is observed at lower redshifts ( z ≲ 2), we observe a definite, nearly monotonic increase in the average SFR with increasing galaxy overdensity over more than an order of magnitude in δ gal . The robustness of this trend is quantified by accounting for both uncertainties in our measurements and galaxy populations that are either underrepresented or not present in our sample (e.g., extremely dusty star-forming and quiescent galaxies), and we find that the trend remains significant under all circumstances. This trend appears to be primarily driven by the fractional increase of galaxies in high-density environments that are more massive in their stellar content and are forming stars at a higher rate than their less massive…

Context. During their lifetimes, galaxy clusters grow through the accretion of matter from the filaments of the large-scale structure and from mergers with other clusters. These mergers release a large amount of energy into the intracluster medium (ICM) through merger shocks and turbulence. These phenomena are associated with the formation of radio sources known as radio relics and radio halos, respectively. Radio relics and halos are unique proxies for studying the complex properties of these dynamically active regions of clusters and the microphysics of the ICM more generally. Aims. Abell 3667 is a spectacular example of a merging system that hosts a large pair of radio relics. Due to its proximity ( z = 0.0553) and large mass, the system enables the study of these sources to a uniquely high level of detail. However, being located at Dec = −56.8°, the cluster could only be observed with a limited number of radio facilities. Methods. We observed Abell 3667 with MeerKAT as part of the MeerKAT Galaxy Cluster Legacy Survey. We used these data to study the large-scale emission of the…

We present a new strong lensing (SL) model of the Hubble Frontier Fields (HFF) galaxy cluster Abell 2744, at z = 0.3072, by exploiting archival Hubble Space Telescope (HST) multiband imaging and Multi Unit Spectroscopic Explorer (MUSE) follow-up spectroscopy. The lens model considers 90 spectroscopically confirmed multiple images (from 30 background sources), representing the largest secure sample for this cluster field prior to the recently acquired James Webb Space Telescope (JWST) observations. The inclusion of the substructures within several extended sources as model constraints allowed us to accurately characterize the inner total mass distribution of the cluster and the position of the cluster critical lines. We included the lensing contribution of 225 cluster members, 202 of which are spectroscopically confirmed. We complemented this sample with 23 photometric member galaxies that are identified with a convolution neural network methodology with a high degree of purity. We also measured the internal velocity dispersion of 85 cluster galaxies, down to m F 160 W = 22, to…

Context. Understanding how star formation begins and propagates through molecular clouds is a fundamental but still open question. One major difficulty in addressing this question is the lack of precise 3D kinematics and age information for young stellar populations. Thanks to astrometry provided by Gaia, large spectroscopic surveys, and improved age-dating methods, this picture is changing. Aims. We aim to study spatial and kinematic substructures of the region encompassed by the Upper Scorpius and Ophiuchus star forming regions. We want to determine dynamical traceback ages and study the star formation history (SFH) of the complex. Methods. We combined our spectroscopic observations with spectra in public archives and large radial velocity surveys to obtain a precise radial velocity sample to complement the Gaia astrometry. We used a Gaussian Mixture Model to identify different kinematic structures in the 6D space of positions and velocities. We applied an orbital traceback analysis to estimate a dynamical traceback age for each group and determine the place where it was born.…

The Einstein Telescope (ET) is going to bring a revolution for the future of multimessenger astrophysics. In order to detect the counterparts of binary neutron star (BNS) mergers at high redshift, the high-energy observations will play a crucial role. Here, we explore the perspectives of ET, as a single observatory and in a network of gravitational-wave (GW) detectors, operating in synergy with future γ-ray and X-ray satellites. We predict the high-energy emission of BNS mergers and its detectability in a theoretical framework which is able to reproduce the properties of the current sample of observed short GRBs (SGRBs). We estimate the joint GW and high-energy detection rate for both the prompt and afterglow emissions, testing several combinations of instruments and observational strategies. We find that the vast majority of SGRBs detected in γ-rays have a detectable GW counterpart; the joint detection efficiency approaches 100% considering a network of third-generation GW observatories. The probability of identifying the electromagnetic counterpart of BNS mergers is significantly…

Context.The motion of stars has been used to reveal details of the complex history of the Milky Way, in constant interaction with its environment. Nevertheless, to reconstruct the Galactic history puzzle in its entirety, the chemo-physical characterisation of stars is essential. PreviousGaiadata releases were supported by a smaller, heterogeneous, and spatially biased mixture of chemical data from ground-based observations. Aims.GaiaData Release 3 opens a new era of all-sky spectral analysis of stellar populations thanks to the nearly 5.6 million stars observed by the Radial Velocity Spectrometer (RVS) and parametrised by the GSP-Spec module. In this work, we aim to demonstrate the scientific quality ofGaia’s Milky Way chemical cartography through a chemo-dynamical analysis of disc and halo populations. Methods.Stellar atmospheric parameters and chemical abundances provided byGaiaDR3 spectroscopy are combined with DR3 radial velocities and EDR3 astrometry to analyse the relationships between chemistry and Milky Way structure, stellar kinematics, and orbital parameters. Results.The…

Context. Massive binaries hosting a black hole (OB+BH) represent a critical phase in the production of BH mergers in the context of binary evolution. In spite of this, such systems have so far largely avoided detection. Single-lined spectroscopic (SB1) O-type binaries are ideal objects to search for elusive BH companions. Moreover, SB1 binaries hosting two main sequence stars probe a regime of more extreme mass ratios and longer periods compared to double-lined binaries (SB2), and they are thus valuable for establishing the natal mass ratio distribution of massive stars. Aims. We characterise the hidden companions in 51 SB1 O-type and evolved B-type binaries identified in the Large Magellanic Cloud (LMC) in the framework of the VLT-FLAMES Tarantula Survey (VFTS) and its follow-up, the Tarantula Massive Binary Monitoring (TMBM). The binaries cover periods between a few days to years (0 < log P < 3 [d]). Our goals are to hunt for BHs and sample the low-mass end of the mass-ratio distribution. Methods. To uncover the hidden companions, we implemented the shift-and-add grid…

The astrometric satellite Gaia recently released part of its third data set, which provides a good opportunity to hunt for more open clusters in the Milky Way. In this work, we conduct a blind search for open clusters in the Galactic disk using a sample-based clustering search method with high spatial resolution, which is especially suited to finding hidden targets. In addition to confirming 1930 previously known open clusters and 82 known globular clusters, 704 new stellar clusters are proposed as potential open clusters at Galactic latitudes of |b|≤20°. For each of these new open clusters, we present the coordinates, detailed astrometric parameters, and ages, as well as the radial velocity, if available. Our blind search greatly increases the number of Galactic open clusters as objects of study and shows the incompleteness of the open cluster census across our Galaxy.

We present a cosmic shear analysis with an improved redshift calibration for the fourth data release of the Kilo-Degree Survey (KiDS-1000) using self-organising maps (SOMs). Compared to the previous analysis of the KiDS-1000 data, we expand the redshift calibration sample to more than twice its size, now consisting of data of 17 spectroscopic redshift campaigns, and significantly extending the fraction of KiDS galaxies we are able to calibrate with our SOM redshift methodology. We then enhanced the calibration sample with precision photometric redshifts from COSMOS2015 and the Physics of the Accelerated Universe Survey (PAUS), allowing us to fill gaps in the spectroscopic coverage of the KiDS data. Finally we performed a Complete Orthogonal Sets of E/B-Integrals (COSEBIs) cosmic shear analysis of the newly calibrated KiDS sample. We foundS8 = 0.748−0.025+0.021, which is in good agreement with previous KiDS studies and increases the tension with measurements of the cosmic microwave background to 3.4σ. We repeated the redshift calibration with different subsets of the full calibration…

Aims. The processes that determine the stellar initial mass function (IMF) and its origin are critical unsolved problems, with profound implications for many areas of astrophysics. The W43-MM2&MM3 mini-starburst ridge hosts a rich young protocluster, from which it is possible to test the current paradigm on the IMF origin. Methods. The ALMA-IMF Large Program observed the W43-MM2&MM3 ridge, whose 1.3 mm and 3 mm ALMA 12 m array continuum images reach a ~2500 au spatial resolution. We used both the best-sensitivity and the line-free ALMA-IMF images, reduced the noise with the multi-resolution segmentation technique MnGSeg, and derived the most complete and most robust core catalog possible. Using two different extraction software packages, getsf and GExt2D, we identified ~200 compact sources, whose ~100 common sources have, on average, fluxes consistent to within 30%. We filtered sources with non-negligible free-free contamination and corrected fluxes from line contamination, resulting in a W43-MM2&MM3 catalog of 205 getsf cores. With a median deconvolved FWHM size of 3400 au, core…