bluuebunny/crossref_metadata_2025 huggingface dataset:
SN 2021adxl: A luminous nearby interacting supernova in an extremely low-metallicity environment
Authors: Brennan S. J. , Schulze S. , Lunnan R. , Sollerman J. , Yan L. , Fransson C. , Irani I. , Melinder J. , Chen T.-W. , De K. , Fremling C. , Kim Y.-L. , Perley D. , Pessi P. J. , Drake A. J. , Graham M. J. , Laher R. R. , Masci F. J. , Purdum J. , Rodriguez H.
Published: July 2024

SN 2021adxl is a slowly evolving, luminous, Type IIn supernova with asymmetric emission line profiles, similar to the well-studied SN 2010jl. We present extensive optical, near-ultraviolet, and near-infrared photometry and spectroscopy covering ∼1.5 years post discovery. SN 2021adxl occurred in an unusual environment, atop a vigorously star-forming region that is offset from its host galaxy core. The appearance of Lyα and O II, as well as the compact core, would classify the host of SN 2021adxl as a “Blueberry” galaxy, analogous to higher redshift, low-metallicity, star-forming dwarf “Green Pea” galaxies. Using several abundance indicators, we find a metallicity of the explosion environment of only ∼0.1 Z⊙, the lowest reported metallicity for a Type IIn SN environment. SN 2021adxl reaches a peak magnitude of Mr ≈ −20.2 mag and since discovery, SN 2021adxl has faded by only ∼4 magnitudes in the r band with a cumulative radiated energy of ∼1.5 × 1050 erg over 18 months. SN 2021adxl shows strong signs of interaction with a complex circumstellar medium, seen by the detection of X-rays, revealed by the detection of coronal emission lines, and through multi-component hydrogen and helium profiles. In order to further understand this interaction, we model the Hα profile using a Monte Carlo electron scattering code. The blueshifted high-velocity component is consistent with emission from a radially thin spherical shell resulting in the broad emission components due to electron scattering. Using the velocity evolution of this emitting shell, we find that the SN ejecta collide with circumstellar material of at least ∼5 M⊙ assuming a steady-state mass-loss rate of ∼4 − 6 × 10−3 M⊙ yr−1 for the first ∼200 days of evolution. SN 2021adxl was last observed to be slowly declining at ∼0.01 mag d−1, and if this trend continues, SN 2021adxl will remain observable after its current solar conjunction. Continuing the observations of SN 2021adxl may reveal signatures of dust formation or an infrared excess, similar to that seen for SN 2010jl.
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.
A global view on star formation: The GLOSTAR Galactic plane survey
Authors: Khan S. , Rugel M. R. , Brunthaler A. , Menten K. M. , Wyrowski F. , Urquhart J. S. , Gong Y. , Yang A. Y. , Nguyen H. , Dokara R. , Dzib S. A. , Medina S.-N. X. , Ortiz-León G. N. , Pandian J. D. , Beuther H. , Veena V. S. , Neupane S. , Cheema A. , Reich W. , Roy N.
Published: July 2024

Studies of Galactic H II regions are of crucial importance for studying star formation and the evolution of the interstellar medium. Gaining an insight into their physical characteristics contributes to a more comprehensive understanding of these phenomena. The GLOSTAR project aims to provide a GLObal view on STAR formation in the Milky Way by performing an unbiased and sensitive survey. This is achieved by using the extremely wideband (4–8 GHz) C-band receiver of the Karl G. Jansky Very Large Array and the Effelsberg 100 m telescope. Using radio recombination lines observed in the GLOSTAR survey with the VLA in D-configuration with a typical line sensitivity of 1 σ ~ 3.0 mJy beam−1 at ~5 km s−1 and an angular resolution of 25″, we cataloged 244 individual Galactic H II regions (−2° ≤ ℓ ≤ 60° and |b| ≤ 1°, and 76° ≤ ℓ ≤ 83° and −1° ≤ b ≤ 2°) and derived their physical properties. We examined the mid-infrared (MIR) morphology of these H II regions and find that a significant portion of them exhibit a bubble-like morphology in the GLIMPSE 8 μm emission. We also searched for associations with the dust continuum and sources of methanol maser emission, other tracers of young stellar objects, and find that 48% and 14% of our H II regions, respectively, are coextensive with those. We measured the electron temperature for a large sample of H II regions within Galactocentric distances spanning from 1.6 to 13.1 kpc and derived the Galactic electron temperature gradient as ~372 ± 28 K kpc−1 with an intercept of 4248 ± 161 K, which is consistent with previous studies.
eROSITA narrowband maps at the energies of soft X-ray emission lines
Authors: Zheng Xueying , Ponti Gabriele , Locatelli Nicola , Sanders Jeremy , Merloni Andrea , Becker Werner , Comparat Johan , Dennerl Konrad , Freyberg Michael , Maitra Chandreyee , Sasaki Manami , Strong Andrew , Yeung Michael C. H.
Published: July 2024

Hot plasma plays a crucial role in regulating the baryon cycle within the Milky Way, flowing from the energetic sources in the Galactic center and plane, to the corona and the halo. This hot plasma represents an important fraction of the Galactic baryons, plays a key role in galactic outflows and is an important ingredient in galaxy evolution models. Taking advantage of the Spectrum-Roentgen-Gamma (SRG)/eROSITA first all-sky survey (eRASS1), in this work our aim is to provide a panoramic view of the hot circumgalactic medium (CGM) of the Milky Way. Compared to the previous all-sky X-ray survey performed by ROSAT, the improved energy resolution of eROSITA enabled us to map, for the first time, the sky within the narrow energy bands characteristic of soft X-ray emission lines. These lines provide essential information on the physical properties of the hot plasma. Here we present the eROSITA eRASS1 half sky maps in narrow energy bands corresponding to the most prominent soft X-ray lines, O VII and O VIII, which allowed us to constrain the distribution of the hot plasma within and surrounding the Milky Way. We corrected the maps by removing the expected contribution associated with the cosmic X-ray background, the time-variable solar wind charge exchange, and the local hot bubble. We applied corrections to mitigate the effect of absorption, therefore highlighting the emission from the CGM of the Milky Way. We used the line ratio of the oxygen lines as a proxy to constrain the temperature of the warm-hot CGM, and we defined a pseudo-temperature 𝒯 map. The map highlights how different regions are dominated by different thermal components. Toward the outer halo, the temperature distribution of the CGM on angular scales of 2–20 deg is consistent with being constant Δ𝒯/⟨𝒯⟩≤4%, with a marginal detection of Δ𝒯/⟨𝒯⟩ = 2.7%±0.2% (statistical) ±0.6% (systematic) in the southern hemisphere. Instead, significant variations of ∼12% are observed on scales of many tens of degrees when comparing the northern and southern hemispheres. The pseudo-temperature map shows significant variations across the borders of the eROSITA bubbles, suggesting temperature variations, possibly linked to shocks, between the interior of the Galactic outflow and the unperturbed CGM. In particular, a shell characterized by a lower line ratio appears close to the edge of the eROSITA bubbles.
Clues on the nature of the quasi-periodic optical outbursts of the blazar OJ 287
Authors: Gopal-Krishna
Published: July 2024

The fascination with the blazar OJ 287 stems not only from its status as a prominent candidate for a close supermassive black hole (SMBH) binary, but also because of the thermal bremsstrahlung origin proposed for its giant optical outbursts. These outbursts arrive as pairs, quasi-periodically every ∼12 years, based on the unique 130-year-long, well-sampled optical light curve available for this blazar. For its three well-known, large quasi-periodic optical outbursts (QPOOs), observed in 1983, 2007 and 2015, optical photo-polarimetric monitoring has been reported in the literature. For these initially radio-undetected QPOOs, widely acclaimed as ‘bremsstrahlung flares’, we have scrutinised the available measurements of optical polarisation and spectral index during the rising phase. Several inconsistencies of these data with the optical bremsstrahlung interpretation are noted, which point towards a synchrotron-dominated alternative interpretation for all these prominent QPOOs, just as for the optical emission observed between the outbursts. Possible reasons for the radio non-detection of the QPOOs during the initial stage are outlined.
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.
A lack of Lyman α emitters within 5 Mpc of a luminous quasar in an overdensity at z = 6.9: Potential evidence of negative quasar feedback at protocluster scales
Authors: Lambert Trystan S. , Assef R. J. , Mazzucchelli C. , Bañados E. , Aravena M. , Barrientos F. , González-López J. , Hu W. , Infante L. , Malhotra S. , Moya-Sierralta C. , Rhoads J. , Valdes F. , Wang J. , Wold I. G. B. , Zheng Z.
Published: July 2024

High-redshift quasars are thought to live in the densest regions of space, which should be made evident by an overdensity of galaxies around them. However, campaigns to identify these overdensities by searching for Lyman-break galaxies (LBGs) and Lyman α emitters (LAEs) have had mixed results. These may be explained by either the small field of view of some of the experiments, the broad redshift ranges targeted by LBG searches, and the inherently high uncertainty of quasar redshifts estimated from ultraviolet emission lines, which makes it difficult to place the Ly-α emission line within a narrowband filter. Here, we present a 3 square degree search (∼1000 pMpc2) for LAEs around the z = 6.9 quasar VIK J2348–3054 using the Dark Energy CAMera (DECam) housed on the 4m Blanco telescope, finding 38 LAEs. The systemic redshift of VIK J2348–3054 is known from ALMA [CII] observations and places the Ly-α emission line of companions within the NB964 narrowband of DECam. This is the largest field-of-view LAE search around a z > 6 quasar conducted to date. We find that this field is ∼ten times more overdense than Chandra Deep-Field South, observed previously with the same instrumental setup as well as several combined blank fields. This is strong evidence that VIK J2348–3054 resides in an overdensity of LAEs over several Mpc. Surprisingly, we find a lack of LAEs within 5 physical Mpc of the quasar and take this to most likely be evidence of quasar-suppressing star formation in its immediate vicinity. This result highlights the importance of performing overdensity searches over large areas to properly assess the density of those regions of the Universe.
[Fe II] 1.644 µm imaging survey of planetary nebulae with low-ionisation structures
Authors: Akras S. , Aleman I. , Gonçalves D. R. , Ramos-Larios G. , Bouvis K.
Published: July 2024

Low-ionisation structures (LISs) are commonly found in planetary nebulae (PNe), but they are still poorly understood. The recent discovery of unforeseen molecular hydrogen gas (H2) has impacted what we think we know about these microstructures and PNe. To obtain an overall understanding of LISs, we carried out an [Fe II] 1.644 µm imagery survey in PNe with LISs, with the aim to detect the [Fe II] 1.644µm emission line, a common tracer of shocks. We present the first detection of [Fe II] 1.644 µmline directly associated with the LISs in four out of five PNe. The theoretical H I 12-4 recombination line was also computed either from the Brγ or the Hβ line and subtracted from the observed narrow-band line fluxes. The [Fe II] 1.644 µm flux ranges from 1 to 40 ×10−15 ergs cm−2 s−1 and the intensity from 2 to 90 ×10−5 erg s−1 cm−2 sr−1. The R(Fe)=[Fe II] 1.644 µm/Brγ line ratio was also computed and found to range between 0.5 and 7. In particular, the [Fe II] 1.644 µm line was detected in NGC 6543 (R(Fe)<0.15), along with the outer pairs of LISs in NGC 7009 (R(Fe)<0.25) and the jet-like LISs in IC 4634 (R(Fe)~1), and in several LISs in NGC 6571 (2<R(Fe)<7). The low R(Fe) result for NGC 6543 is attributed to the UV radiation from the central star. In contrast, the higher values in NGC 6571 and IC 4634 are indicative of shocks. The moderate R(Fe) in NGC 7009 likely indicates the contribution of both mechanisms.
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.
ALMA high-resolution observations unveil planet formation shaping molecular emission in the PDS 70 disk
Authors: Rampinelli L. , Facchini S. , Leemker M. , Bae J. , Benisty M. , Teague R. , Law C. J. , Öberg K. I. , Portilla-Revelo B. , Cridland A. J.
Published: July 2024

With two directly detected protoplanets, the PDS 70 system is a unique source in which to study the complex interplay between forming planets and their natal environment. The large dust cavity carved by the two giant planets can affect the disk chemistry, and therefore the molecular emission morphology. On the other hand, chemical properties of the gas component of the disk are expected to leave an imprint on the planetary atmospheres. In this work, we reconstruct the emission morphology of a rich inventory of molecular tracers in the PDS 70 disk, and we look for possible chemical signatures of the two actively accreting protoplanets, PDS 70b and c. We leverage Atacama Large Millimeter/submillimeter Array (ALMA) band 6 high-angular-resolution and deep-sensitivity line emission observations, together with image and uv-plane techniques, to boost the detection of faint lines. We robustly detect ring-shaped emission from 12CO, 13CO, C18O, H13CN, HC15N, DCN, H2CO, CS, C2H, and H13CO+ lines in unprecedented detail. Most of the molecular tracers show a peak of the emission inside the millimeter dust peak. We interpret this as the direct impact of the effective irradiation of the cavity wall, as a result of the planet formation process. Moreover, we have found evidence of an O-poor gas reservoir in the outer disk, which is supported by the observations of bright C-rich molecules, the non-detection of SO, and a lower limit on the CS/SO ratio of ~1. Eventually, we provide the first detection of the c-C3H2 transitions at 218.73 GHz, and the marginal detection of an azimuthal asymmetry in the higher-energy H2CO (32,1−22,0) line, which could be due to accretion heating near PDS 70b.
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.
Evolution of the star formation rate and ΣSFR of galaxies at cosmic morning (4  <  z  <  10)
Authors: Calabrò A. , Pentericci L. , Santini P. , Ferrara A. , Llerena M. , Mascia S. , Napolitano L. , Yung L. Y. A. , Bisigello L. , Castellano M. , Cleri N. J. , Dekel A. , Dickinson M. , Franco M. , Giavalisco M. , Hirschmann M. , Holwerda B. W. , Koekemoer A. M. , Lucas R. A. , Pacucci F. , Pirzkal N. , Roberts-Borsani G. , Seillé L. M. , Tacchella S. , Wilkins S. , Amorín R. , Arrabal Haro P. , Bagley M. B. , Finkelstein S. L. , Kartaltepe J. S. , Papovich C.
Published: July 2024

The galaxy-integrated star formation rate (SFR) surface density measurement (ΣSFR) has been proposed as a valuable diagnostic of the mass accumulation in galaxies given it is more tightly related to the physics of star formation and stellar feedback than other indicators. In this work, we assembled a statistical sample of 230 galaxies observed with JWST in the GLASS and CEERS spectroscopic surveys to estimate Balmer line-based dust attenuations and SFRs (i.e., from Hα, Hβ, and Hγ), along with the UV rest-frame effective radii. We studied the evolution of galaxy SFR and ΣSFR in the first 1.5 billion years of our Universe, from a redshift of z ∼ 4 to z ∼ 10. We found that ΣSFR is mildly increasing with redshift with a linear slope of 0.16 ± 0.06. We explored the dependence of SFR and ΣSFR on stellar mass, showing that a star-forming main sequence and a ΣSFR main sequence are present out to z = 10. This dependence exhibits a similar slope compared to the same relations at lower redshifts, but with a higher normalization. We find that the specific SFR (sSFR) and ΣSFR are correlated with the [O III] λ5007 Å/[O II] λ3727 Å ratio and with indirect estimates of the escape fraction of Lyman continuum photons; hence, they are likely to play an important role in the evolution of ionization conditions at higher redshifts and in the escape of ionizing radiation. We also searched for spectral outflow signatures in the Hα and [O III] emission lines in a subset of galaxies observed at high resolution (R = 2700) by the GLASS survey, finding an outflow incidence of 2/11 (=20%32%9%)
at z < 6, but no evidence at z > 6 (0/6, < 26%). Finally, we find a positive correlation between AV and ΣSFR, and a flat trend as a function of sSFR, indicating that there is no evidence of a drop in AV in extremely star-forming galaxies between z ∼ 4 and ∼10. This result might be at odds with a dust-clearing outflow scenario, which may instead take place at redshifts of z ≥ 10, as suggested by some theoretical models.
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.
El Gordo needs El Anzuelo: Probing the structure of cluster members with multi-band extended arcs in JWST data
Authors: Galan A. , Caminha G. B. , Knollmüller J. , Roth J. , Suyu S. H.
Published: July 2024

Gravitational lensing by galaxy clusters involves hundreds of galaxies over a large redshift range and increases the likelihood of rare phenomena (supernovae, microlensing, dark substructures, etc.). Characterizing the mass and light distributions of foreground and background objects often requires a combination of high-resolution data and advanced modeling techniques. We present the detailed analysis of El Anzuelo, a prominent quintuply imaged dusty star-forming galaxy (ɀs = 2.29), mainly lensed by three members of the massive galaxy cluster ACT-CL J0102–4915, also known as El Gordo (ɀd = 0.87). We leverage JWST/NIRCam images, which contain lensing features that were unseen in previous HST images, using a Bayesian, multi-wavelength, differentiable and GPU-accelerated modeling framework that combines HERCULENS (lens modeling) and NIFTY (field model and inference) software packages. For one of the deflectors, we complement lensing constraints with stellar kinematics measured from VLT/MUSE data. In our lens model, we explicitly include the mass distribution of the cluster, locally corrected by a constant shear field. We find that the two main deflectors (L1 and L2) have logarithmic mass density slopes steeper than isothermal, with γL1 = 2.23 ± 0.05 and γL2 = 2.21 ± 0.04. We argue that such steep density profiles can arise due to tidally truncated mass distributions, which we probe thanks to the cluster lensing boost and the strong asymmetry of the lensing configuration. Moreover, our three-dimensional source model captures most of the surface brightness of the lensed galaxy, revealing a clump with a maximum diameter of 400 parsecs at the source redshift, visible at wavelengths λrest ≳ 0.6 µm. Finally, we caution on using point-like features within extended arcs to constrain galaxy-scale lens models before securing them with extended arc modeling.
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.
Linear adiabatic analysis for general-relativistic instability in primordial accreting supermassive stars
Authors: Saio Hideyuki , Nandal Devesh , Ekström Sylvia , Meynet George
Published: July 2024

Accreting supermassive stars of ≳105 M⊙ will eventually collapse directly to a black hole via the general-relativistic (GR) instability. Such direct collapses of supermassive stars are thought to be a possible formation channel for supermassive black holes at z > 6. In this work, we investigate the final mass of accreting Population III stars with constant accretion rates between 0.01 and 1000 M⊙ yr−1. We determined the final mass by solving the differential equation for GR linear adiabatic radial pulsations. We find that models with accretion rates ≳0.05 M⊙ yr−1 experience the GR instability at masses depending on the accretion rates. The critical masses are larger for higher accretion rates, ranging from 8 × 104 M⊙ for 0.05 M⊙ yr−1 to ∼106 M⊙ for 1000 M⊙ yr−1. The 0.05 M⊙ yr−1 model reaches the GR instability at the end of the core hydrogen burning. The higher-mass models with higher accretion rates reach the GR instability during the hydrogen burning stage.
A solar rotation signature in cosmic dust: Frequency analysis of dust particle impacts on the Wind spacecraft
Authors: Baalmann L. R. , Hunziker S. , Péronne A. , Kirchner J. W. , Glassmeier K.-H. , Malaspina D. M. , Wilson III L. B. , Strähl C. , Chadda S. , Sterken V. J.
Published: July 2024

Aims. Dust particle impacts on the Wind spacecraft were detected with its plasma wave instrument Wind/WAVES. Frequency analysis on the resulting dust impact time series has revealed spectral peaks indicative of a solar rotation signature. We investigated whether this solar rotation signature is embedded in the interplanetary or in the interstellar dust (ISD) and whether it is caused by co-rotating interaction regions (CIRs), by the sector structure of the interplanetary magnetic field (IMF), or by external effects.

Methods. We performed frequency analysis on different subsets of the data to investigate the origin of these spectral peaks, comparing segments of Wind’s orbit when the spacecraft moved against or with the ISD inflow direction and comparing the time periods of the ISD focusing phase and the ISD defocusing phase of the solar magnetic cycle. A superposed epoch analysis of the number of dust impacts during CIRs was used to investigate the systematic effect of CIRs. Case studies of time periods with frequent or infrequent occurrences of CIRs were performed and compared to synthetic data of cosmic dust impacts affected by CIRs. We performed similar case studies for time periods with a stable or chaotic IMF sector structure. The superposed epoch analysis was repeated for a time series of the spacecraft floating potential.

Results. Spectral peaks were found at the solar rotation period of ∼27 d and its harmonics at 13.5 d and 9 d. This solar rotation signature may affect both interplanetary and interstellar dust. The appearance of this signature correlates with the occurrence of CIRs but not with the stability of the IMF sector structure. The CIRs cause, on average, a reduction in the number of dust impact detections. Periodic changes of the spacecraft’s floating potential were found to partially counteract this reduction by enhancing the instrument’s sensitivity to dust impacts; these changes of the floating potential are thus unlikely to be the cause of the solar rotation signature.
Neutral atomic and molecular gas dynamics in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496
Authors: Laudage Sebastian , Eibensteiner Cosima , Bigiel Frank , Leroy Adam K. , Meidt Sharon , Schinnerer Eva , de Blok W. J. G. , Querejeta Miguele , Stuber Sophia , Colombo Dario , Rosolowsky Erik , Pisano D. J. , Utomo Dyas , Levy Rebecca C. , Klessen Ralf , Cao Yixian , Koch Eric W. , Kurapati Sushma , Sanchez-Blazquez Patricia , Neumann Justus , Neumann Lukas , Pan Hsi-An , Williams Thomas G.
Published: July 2024

Neutral atomic gas (H I) effectively traces galactic dynamics across mid to large galactocentric radii. However, its limitations in observing small-scale changes within the central few kiloparsecs, coupled with the often observed H Ideficit in galactic centers, necessitates the use of molecular gas emission as a preferred tracer in these regions. Understanding the dynamics of both neutral atomic and molecular gas is crucial for a more complete understanding of how galaxies evolve, funnel gas from the outer disk into their central parts, and eventually form stars. In this work we aim to quantify the dynamics of both, the neutral atomic and molecular gas, in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496 using new MeerKAT H Iobservations together with ALMA CO (2-1) observations from the PHANGS collaboration. We use the analysis tool3DBarolo to fit tilted ring models to the H Iand CO observations. A combined approach of using the H Ito constrain the true disk orientation parameters before applying these to the CO datasets is tested. This paper sets expectations for the results of the upcoming high-resolution H Icoverage of many galaxies in the PHANGS-ALMA sample using MeerKAT or VLA, to establish a robust methodology for characterizing galaxy orientations and deriving dynamics from combing new H Iwith existing CO data.
From traffic jams to roadblocks: The outer regions of TW Hya with ALMA Band 8
Authors: Das S. , Kurtovic N. T. , Flock M.
Published: July 2024

Context. Current ALMA surveys often underestimate protoplanetary disk sizes as many disks have extended low surface-brightness regions that fall below ALMA’s detection limits. To effectively capture faint millimeter continuum emission in these outer regions, increased sensitivity is required.

Aims. In order to gain insights on the connection between disk structure and planet formation, we aim to uncover continuum emission in the outer regions of the disk around TW Hya. Additionally, we aim to investigate the evolution of this disk by studying its dust properties.

Methods. We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 0.65 mm with ~0.5 arcsecond angular resolution, together with high angular resolution archival observations at 0.87,1.3, 2.1 and 3.1 mm. We constrain the outer disk emission with both image-plane retrieval, and visibility-plane modeling with non-parametric and parametric fitting tools.

Results. Our results confirm emission in the outer disk regions of TW Hya (60 au ≤ R ≤ 110 au) at 0.65, 0.87 and 1.3 mm. With image-plane retrieval, we resolve the new continuum gap and ring, namely D79 and B86, at 0.87 and 1.3 mm. With visibility-plane modeling, we also detect this substructure at 0.65 mm in the form of a quasi-constant emission at the 1σ level. Furthermore, it has a high spectral index of 3.7, which may indicate dust grain sizes <<1 mm. It may be a dust trap or a traffic jam, that has a flux density of ~60 mJy and a mass (1.59 M⊕) that accounts for up to 2% of the dust disk at 0.65 mm.

Conclusions. We confirm the existence of a faint ring in the outer regions of TW Hya at multiple millimeter wavelengths. With visibility-plane modeling, we are able to set constrains that are 3 times better than the resolution of our Band 8 observations.
ASASSN-21js: A multi-year transit of a ringed disc
Authors: Pramono T. H. , Kenworthy M. A. , van Boekel R.
Published: July 2024

Aims. The early-type star ASASSN-21js started to fade in 2021, as was detected by the All Sky Automated Survey for Supernovae, undergoing a multi-year eclipse that is still underway. We interpret this event as being due to a structured disc of material transiting in front of the star. The disc is in orbit around a substellar object with the mass and luminosity of a brown dwarf or smaller. We want to determine the expected duration and ending date of the eclipse.

Methods. We modelled a tilted and inclined azimuthally symmetric ring system around an unseen companion and calculated the resulting time-varying light curve as the object transited in front of the star. We made an initial estimate of the ring parameters and used these as inputs to an MCMC algorithm to determine the geometric properties of the rings with associated uncertainties.

Results. The model most consistent with the light curve to date is a two-ring system at high inclination with respect to the line of sight that has a semi-major axis of 71.6 stellar radii. With an estimate of the stellar radius, the transverse velocity is around 0.7 km s−1, which if bound to the star is an orbit with a semi-major axis of around 13 000 au, placing it in the Oort cloud of the parent star. The transit is ongoing and will finish around MJD 61526 (May 1 2027). We encourage the community to continue observing this object in order to understand its properties.