bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Response Mode observations of GRB 160203A: Looking for fine-structure line variability at z = 3.52
Authors: Pugliese G. , Saccardi A. , D’Elia V. , Vergani S. D. , Heintz K. E. , Savaglio S. , Kaper L. , de Ugarte Postigo A. , Hartmann D. H. , De Cia A. , Vejlgaard S. , Fynbo J. P. U. , Christensen L. , Campana S. , van Rest D. , Selsing J. , Wiersema K. , Malesani D. B. , Covino S. , Burgarella D. , De Pasquale M. , Jakobsson P. , Japelj J. , Kann D. A. , Kouveliotou C. , Rossi A. , Tanvir N. R. , Thöne C. C. , Xu D. 
Published: July 2024

Context. Gamma-ray bursts are the most energetic known explosions. Although they fade rapidly, they give us the opportunity to measure redshift and important properties of their host galaxies. We report the photometric and spectroscopic study of the Swift GRB 160203A at z = 3.518, and its host galaxy. Fine-structure absorption lines, detected in the afterglow at different epochs, allow us to investigate variability due to the strong fading background source.
Aims. We obtained two optical to near-infrared spectra of the GRB afterglow with X-shooter on ESO/VLT, 18 minutes and 5.7 hours after the burst, allowing us to investigate temporal changes of fine-structure absorption lines.
Methods. We measured H I column density log N(HI/cm–2) = 21.75 ± 0.10, and several heavy-element ions along the GRB sightline in the host galaxy, among which Si II, Al II, Al III, C II, Ni II, Si IV, C IV, Zn II and Fe II, and Fe II∗ and Si II∗ fine-structure transitions from energetic levels excited by the afterglow, at the common redshift z = 3.518. We measured [M/H]TOT = –0.78 ± 0.13 and a [Zn/Fe]FIT = 0.69 ± 0.15, representing the total (dust corrected) metallicity and dust depletion, respectively. We detected additional intervening systems along the line of sight at ɀ = 1.03, ɀ = 1.26, ɀ = 1.98, ɀ = 1.99, ɀ = 2.20, and ɀ = 2.83. We could not measure significant variability in the strength of the fine-structure lines throughout all the observations and determined an upper limit for the GRB distance from the absorber of d < 300 pc, adopting the canonical UV pumping scenario. However, we note that the quality of our data is not sufficient to conclusively rule out collisions as an alternative mechanism.
Results. GRB 160203A belongs to a growing sample of GRBs with medium resolution spectroscopy, provided by the Swift/X-shooter legacy programme, which enables a detailed investigation of the interstellar medium in high-redshift GRB host galaxies. In particular, this host galaxy shows relatively high metal enrichment and dust depletion already in place when the universe was only 1.8 Gyr old.
Experimental sticking coefficients of CO and N2 on sub-micrometric cosmic grain analogs
Authors: Stadler C. , Laffon C. , Parent Ph. 
Published: July 2024

Context. Measuring the sticking coefficient of molecules pertinent to astrochemistry – such as CO – on substrates that mimic interstellar dust grains is crucial for the comprehensive understanding of gas-grain chemical processes. Although astrochemical models assume a sticking coefficient of 1, recent laboratory experiments on H2O and CO2 have revealed significantly lower values when measured on small grain analogs. As the effect of grain size on molecular adsorption has been largely ignored to date, further experiments are needed to determine the accretion rates of species known to freeze out on dust grains.
Aims. Our aim is to determine the sticking coefficients of CO and N2 on sub-micrometric silicate and carbon grains. By quantifying realistic sticking coefficients on these dust grain analogs, we can improve the accuracy of astrochemists’ predictions of molecular abundances as affected by gas-grain interactions.
Methods. The molecules of interest were added to various substrates at 10 K in an ultra-high vacuum. The amount of adsorbate that stuck to the substrate was quantified using X-ray photoelectron spectroscopy. These quantities were compared to a reference with a sticking coefficient of 1, allowing the deduction of the sticking coefficient for each substrate.
Results. The average sticking coefficients of CO and N2 on grain analogs are 0.17 for CO and 0.14 for N2 on olivine powder, and 0.05 for CO and 0.07 on N2 on soot, instead of the presumed 1. This is in line with the low values previously reported for H2O and CO2.
Conclusions. These laboratory results indicate that CO and N2, in addition to H2O and CO2, also exhibit a low sticking coefficient on dust grain analogs. It is thus necessary to reconsider the interactions between gaseous species and dust particles as a low-efficiency process. This reduction in accretion and reaction rates has important implications for how we understand astrochemistry.
Empirical derivation of the metallicity evolution with time and radius using TNG50 Milky Way and Andromeda analogues
Authors: Ratcliffe B. , Khoperskov S. , Minchev I. , Lu L. , de Jong R. S. , Steinmetz M. 
Published: July 2024

Context. Recent works use a linear birth metallicity gradient to estimate the evolution of the [Fe/H] profile in the Galactic disk over time, and infer stellar birth radii (Rbirth) from [Fe/H] and age measurements. These estimates rely on the evolution of [Fe/H] at the Galactic center ([Fe/H](0, τ)) and the birth metallicity gradient (∇[Fe/H](τ)) over time – quantities that are unknown and inferred under key assumptions.
Aims. In this work, we use the sample of Milky Way and Andromeda analogues from the TNG50 simulation to investigate the ability to recover [Fe/H](R, τ) in a variety of galaxies.
Methods. Using stellar disk particles, we tested the assumptions required in estimating Rbirth, [Fe/H](0, τ), and ∇[Fe/H](τ) using recently proposed methods to understand when they are valid.
Results. We show that ∇[Fe/H](τ) can be recovered in most galaxies to within 26% from the range in [Fe/H] across age, with better accuracy for more massive and stronger barred galaxies. We also find that the true central metallicity is unrepresentative of the genuine disk [Fe/H] profile; thus we propose to use a projected central metallicity instead. About half of the galaxies in our sample do not have a continuously enriching projected central metallicity, with a dilution in [Fe/H] correlating with mergers. Most importantly, galaxy-specific [Fe/H](R, τ) can be constrained and confirmed by requiring the Rbirth distributions of mono-age, solar neighborhood populations to follow inside-out formation.
Conclusions. We conclude that examining trends with Rbirth is valid for the Milky Way disk and similarly structured galaxies, where we expect Rbirth can be recovered to within 20% assuming today’s measurement uncertainties in TNG50.
Extragalactic 85Rb/87Rb and 6Li/7Li ratios in the Small Magellanic Cloud
Authors: Molaro P. , Bonifacio P. , Cupani G. , Howk J. C. 
Published: July 2024

Aims. The line of sight toward Sk 143 (AzV 456), an O9.5 Ib star in the Small Magellanic Cloud (SMC), shows significant absorption from neutral atoms and molecules. We report a new study of this line of sight by means of high-resolution spectra obtained with the ESPRESSO spectrograph at the VLT of ESO.
Methods. The absorption from neutral and ionized species is well characterized by a single component at vhel ≈ +132 km s−1 that was modeled with the ASTROCOOK code.
Results. The rubidium Rb I 780.0 nm line is detected for the first time outside the Galaxy, and we derive [Rb/H] = −1.86 ± 0.09. As a result of the high resolution, the 85Rb and 87Rb isotope lines are also exceptionally well resolved. The 85Rb/87Rb isotope ratio is 0.46, which is opposite of the meteoritic value of 2.43. This implies that Rb is made through a dominant contribution of the r-process, which is dominant for the 87Rb isotope. We also confirm the presence of 7Li I 670.7 nm and set a limit on the isotopic ratio of 6Li/7Li < 0.1.
Conclusions. The dominance of the 87Rb isotope implies that Rb is made through a dominant contribution of the r-process. At the low metallicity of the cloud of [Zn/H] = −1.28 ± 0.09, neutron rich material may have occurred in rotating metal-poor massive stars. Moreover, the low metallicity of the cloud leads to an absolute Li abundance of A(7Li) ≈ 2.2, which differs from the expectation from big bang nucleosynthesis. Because the gas-phase abundance is not affected by stellar depletion, the burning of Li inside the halo stars is probably not the solution for the cosmological 7Li problem.
Tidal dissipation in evolved low- and intermediate-mass stars
Authors: Esseldeurs M. , Mathis S. , Decin L. 
Published: July 2024

Context. As the observed occurrence for planets or stellar companions orbiting low- and intermediate-mass evolved stars is increasing, so is the importance of understanding and evaluating the strength of their interactions. This is important for the further evolution of both our own Earth-Sun system and most of the observed exoplanetary systems. One of the most fundamental mechanisms behind this interaction is the tidal dissipation in these stars, as it is one of the engines of the orbital and rotational evolution of star-planet and star-star systems.
Aims. This article builds upon previous works that studied the evolution of the tidal dissipation along the pre-main sequence and the main sequence of low- and intermediate-mass stars and found a strong link between the structural and rotational evolution of stars and tidal dissipation. This article provides, for the first time, a complete picture of tidal dissipation along the entire evolution of low- and intermediate-mass stars, including the advanced phases of evolution.
Methods. Using stellar evolutionary models, the internal structure of the star was computed from the pre-main sequence all the way up to the white dwarf phase for stars with initial masses between 1 and 4 M⊙. Using this internal structure, the tidal dissipation was computed along the entire stellar evolution. Tidal dissipation was separated into two components: the dissipation of the equilibrium (non-wave-like) tide and the dissipation of the dynamical (wave-like) tide. For evolved stars, the dynamical tide is constituted by progressive internal gravity waves. The evolution of the tidal dissipation was investigated for both the equilibrium and dynamical tides, and the results were compared.
Results The significance of both the equilibrium and dynamical tide dissipation becomes apparent within distinct domains of the parameter space. The dissipation of the equilibrium tide is dominant when the star is large or the companion is far from the star. Conversely, the dissipation of the dynamical tide is important when the star is small or the companion is close to the star. The size and location of these domains depend on the masses of both the star and the companion, as well as on the evolutionary phase.
Conclusions Both the equilibrium and the dynamical tides are important in evolved stars, and therefore both need to be taken into account when studying the tidal dissipation in evolved stars and the evolution of the planetary and/or stellar companions orbiting them.
Thermodynamical stability of [CNN and NCN] sequences as indication of most abundant structures in the ISM
Authors: Chataigner I. , Pauzat F. , Tasseau O. , Ellinger Y. , Guillemin J.-C. 
Published: July 2024

Context. Most of the molecules identified in the interstellar medium (ISM) are organic compounds and more than 50 have one isomer or more. Statistically, the most stable isomer of a given chemical formula is the most abundant. This occurrence is verified up to ~90% of the detected species leading to the so-called minimum energy principle (MEP).
Aims. Our main objective is to increase the list of the 14 bis-nitrogen species already detected. We focus on ten CxHyNz isomer families with x = (1, 2, 3), y = (0, 2, 4, 6, 8), z = 2. To this end, we look for a reliable and economic way to provide energy scales.
Methods. We employed standard quantum chemistry methods to determine the relative position of each isomer on the energy scales of each family. We systematically applied density functional theory (DFT) treatments using basis sets of increasing size and quality (6-311++G** and cc-pVQZ). When reasonably feasible, we then performed high-level coupled cluster calculations (CCSD) using the same basis sets to refine relative energies.
Results. All 14 bis-nitrogen species already identified in the ISM indeed satisfy the MEP. We determine the relative thermodynamic stability of the isomers with a CxHyN2 formula of each of the ten sets (94 compounds altogether), and hightlight those that are potentially detectable. By increasing the number of carbon atoms, we find 15 compounds that are by far the most stable candidates.
Conclusions. We confirm that, within the limits of thermodynamics, MEP is an efficient and easily applicable tool for identifying the isomers in a given series that have a greater probability of being detected. Computationally, the combination “B3LYP/cc-pVQZ” provides a suitable compromise for determining energy differences and dipole moments. Clearly, the isomers containing the [NCN] sequence should be prioritized over those with [CNN] in future observation campaigns.
Differential image motion in astrometric observations with very large seeing-limited telescopes
Authors: Lazorenko P. F. , Sahlmann J. , Mayor M. , Martin E. L. 
Published: July 2024

Aims. We investigate how to quantitatively model the observed differential image motion (DIM) in relative astrometric observations.
Methods. As a test bed we used differential astrometric observations from the FORS2 camera of the Very Large Telescope (VLT) obtained during 2010–2019 under several programs of observations of southern brown dwarfs. The measured image motion was compared to models that decompose atmospheric turbulence in frequency space and translate the vertical turbulence profile into DIM amplitude. This approach accounts for the spatial filtering by the telescope’s entrance pupil and the observation parameters (field size, zenith angle, reference star brightness and distribution, and exposure time), and it aggregates that information into a newly defined metric integral term.
Results. We demonstrate excellent agreement (within 1%) between the model parameters derived from the DIM variance and determined by the observations. For a 30 s exposure of a typical 1′-radius field close to the Galactic plane, image motion limits astrometric precision to ~60 μas when sixth-order transformation polynomial is applicable. We confirm that the measured image motion variance is well described by Kolmogorov-type turbulence with exponent 11/3 dependence on the field size at effective altitudes of 16–18 km, where the best part of the DIM is generated. Extrapolation to observations with extremely large telescopes enables the estimation of the astrometric precision limit for seeing-limited observations of ~5 μas, which has a variety of exciting scientific applications.
Cosmic Type Ia supernova rate and constraints on supernova Ia progenitors
Authors: Palicio P. A. , Matteucci F. , Della Valle M. , Spitoni E. 
Published: July 2024

Context. Type Ia supernovae play a key role in the evolution of galaxies by polluting the interstellar medium with a fraction of iron peak elements larger than that released in the core-collapse supernova events. Their light curve, moreover, is widely used in cosmological studies as it constitutes a reliable distance indicator on extragalactic scales. Among the mechanisms proposed to explain the Type Ia supernovae (SNe), the single- and double-degenerate channels are thought to be the dominant ones, which implies a different distribution of time delays between the progenitor formation and the explosion.
Aims. In this paper, we aim to determine the dominant mechanism by comparing a compilation of Type Ia SN rates with those computed from various cosmic star-formation histories coupled with different delay-time distribution functions. We also evaluate the relative contributions of both channels.
Methods. By using a least-squares fitting procedure, we modeled the observations of Type Ia SN rates assuming different combinations of three recent cosmic star-formation rates and seven delay-time distributions. The goodness of these fits are statistically quantified by the χ2 test.
Results. For two of the three cosmic star-formation rates, the single degenerate scenario provides the most accurate explanation for the observations, while a combination of 34% single-degenerate- and 66% double-degenerate delay-time distributions is more plausible for the remaining tested cosmic star-formation rates.
Conclusions. Though dependent on the assumed cosmic star-formation rate, we find arguments in favor of the single-degenerate model. From the theoretic point of view, at least ∼34% of the Type Ia SN must have been produced through the single-degenerate channel to account for the observations. The wide, double-degenerate mechanism slightly under-predicts the observations at redshift z ≳ 1, unless the cosmic SFR flattens in that regime. On the contrary, although the purely close double-degenerate scenario can be ruled out, we cannot rule out a mixed scenario with single- and double-degenerate progenitors.
Tidal tails of open clusters
Authors: Kos Janez 
Published: July 2024

Context. Open clusters that emerged from the star-forming regions as gravitationally bound structures are subjected to star evaporation, ejection, and tidal forces throughout the rest of their lives. Consequently, they form tidal tails that can stretch kiloparsecs along the cluster’s orbit.
Aims. Cluster members are typically found by searching for overdensities in some parameter space (positions and velocities or sometimes actions and orbital parameters of stars). However, this method is not effective at identifying stars located in the tidal tails far from the open cluster cores. We present a probabilistic method for finding distant cluster members without relying on a search for overdensities and apply it to 476 open clusters.
Methods. First, we simulated the dissolution of a cluster and obtained a probability distribution (likelihood) describing where cluster members are to be found. The distribution of stars from the Gaia DR3 catalogue in high likelihood regions was then compared to the simulated stellar population of the Galaxy to define the membership probability of each star.
Results. The survey of cluster members included all stars with a magnitude of G < 17.5 and larger clusters with an age of > 100 Myr within 3 kpc from the Sun. We successfully found stars with high membership probabilities in the tidal tails of most clusters. The recovered tidal tails stretch more than a kiloparsec from the cluster cores in some cases. We analysed the morphological properties of the tidal tails and demonstrated how properly normalised membership probabilities aid systematic studies of open clusters. Finally, we have published a catalogue of stars found in the tidal tails.
Fate of a remnant solid disk around an eccentric giant planet
Authors: Shibata S. , Helled R. 
Published: July 2024

Context. The composition of giant planets’ atmospheres is an important tracer of their formation history. While many theoretical studies investigate the heavy-element accretion within a gaseous protoplanetary disk, the possibility of solid accretion after disk dissipation has not been explored.
Aims. Here, we focus on the case of a gas giant planet excited to an eccentric orbit and assess the likelihood of solid accretion after disk dissipation. We follow the orbital evolution of the surrounding solid materials and investigate the scattering and accretion of heavy elements in the remnant solid disks.
Methods. We perform N-body simulations of planetesimals and embryos around an eccentric giant planet. We consider various sizes and orbits for the eccentric planet and determine the fate of planetesimals and embryos.
Results. We find that the orbital evolution of solids, such as planetesimals and embryos, is regulated by weak encounters with the eccentric planet rather than strong close encounters. Even in the region where the Safronov number is smaller than unity, most solid materials fall onto the central star or are ejected from the planetary system. We also develop an analytical model of the solid accretion along the orbital evolution of a giant planet, where the accretion probability is obtained as a function of the planetary mass, radius, semi-major axis, eccentricity, inclination, and solid disk thickness.
Conclusions. Our model predicts that ~0.01–0.1 M⊕ of solids is accreted onto an eccentric planet orbiting in the outer disk (~10 au). The accreted heavy-element mass increases (decreases) with the eccentricity (inclination) of the planet. We also discuss the possibility of collisions of terrestrial planets and find that ~ 10% of the hot Jupiters formed via high-eccentric migration collide with a planet of 10 M⊕. However, we find that solid accretion and collisions with terrestrial planets are minor events for planets in the inner orbit, and a different accretion process is required to enrich eccentric giant planets with heavy elements.
Peering above the clouds of the warm Neptune GJ 436 b with CRIRES+
Authors: Grasser Natalie , Snellen Ignas A. G. , Landman Rico , Picos Darío González , Gandhi Siddharth 
Published: July 2024

Context. Exoplanets with masses between Earth and Neptune are amongst the most commonly observed, yet their properties are poorly constrained. Their transmission spectra are often featureless, which indicate either high-altitude clouds or a high atmospheric metallicity. The archetypical warm Neptune GJ 436 b is such a planet showing a flat transmission spectrum in observations with the Hubble Space Telescope (HST).
Aims. Ground-based high-resolution spectroscopy (HRS) effectively probes exoplanet atmospheres at higher altitudes and can therefore be more sensitive to absorption coming from above potential cloud decks. In this paper we aim to investigate this for the exoplanet GJ 436b.
Methods. We present new CRIRES+ HRS transit data of GJ 436 b. Three transits were observed, but since two were during bad weather conditions, only one transit was analyzed. The radiative transfer code petitRADTRANS was used to create atmospheric models for cross-correlation and signal-injection purposes, including absorption from H2O, CH4, and CO.
Results. No transmission signals were detected, but atmospheric constraints can be derived. Injection of artificial transmission signals indicate that if GJ 436 b would have a cloud deck at pressures P > 10 mbar and a <300× solar metallicity, these CRIRES+ observations should have resulted in a detection.
Conclusions. We estimate that the constraints presented here from one ground-based HRS transit are slightly better than those obtained with four HST transits. Combining HRS data from multiple transits is an interesting avenue for future studies of exoplanets with high-altitude clouds.