Showing new listings for Monday, 13 October 2025

[olozhika]

Showing new listings for Monday, 13 October 2025

Auto update Star Formation & Molecular Cloud papers at about 2:30am UTC (10:30am Beijing time) every weekday.

阅读 Usage.md了解如何使用此repo实现个性化的Arxiv论文推送

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Keyword list: ['star formation', 'star-forming', 'molecular cloud', 'interstellar medium', 'cloud', 'clump', 'core', 'filament', 'atomic gas', 'N-PDF']

Excluded: ['galaxies', 'galaxy cluster', ' AGN ', 'standard candle', 'X-ray binar', 'solar corona']

Today: 12papers

Tracing Planetary Accretion in a 3 Gyr-old Hydrogen-Rich White Dwarf: The Extremely Polluted Atmosphere of LSPM J0207+3331

• Authors: Érika Le Bourdais, Patrick Dufour, Carl Melis, Beth L. Klein, Laura K. Rogers, Antoine Bédard, John Debes, Ashley Messier, Alycia J. Weinberger, Siyi Xu

• Subjects: Subjects:
  Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

• Arxiv link: https://arxiv.org/abs/2510.08676

• Pdf link: https://arxiv.org/pdf/2510.08676

• Abstract
  We report the detection of 13 heavy elements (Na, Mg, Al, Si, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, and Sr) in the photosphere of LSPM J0207+3331, a ~3 Gyr old hydrogen-rich white dwarf with an effective temperature comparable to that of the Sun. Upper limits on carbon, obtained through the absence of molecular CH, suggest accretion from a carbon-volatile-depleted source. The accreted parent body exhibits slight deficits of Mg and Si relative to Fe but otherwise bulk Earth-like abundance patterns; a reasonable interpretation is that LSPM J0207+3331 is accreting a massive differentiated rocky body that had a core mass fraction higher than the Earth's. The high level of pollution indicates that substantial accretion events can still occur even after 3 Gyr of cooling. We also detect weak Ca II H & K line-core emission, making this only the second known isolated polluted white dwarf to exhibit this phenomenon and suggesting the presence of additional physical processes in or above the upper atmosphere. Our analysis also highlights the critical importance of including heavy elements in the model atmosphere structure calculations for highly polluted hydrogen-rich white dwarfs. Neglecting their contribution significantly impacts the inferred thermodynamic structure, leading to inaccuracies in derived stellar parameters. Finally, we show that the observed 11.3 microns infrared excess can be explained by a single silicate dust disk rather than a two-ring disk model.

Next-Generation Improvements in Giant Exoplanet Evolutionary and Structural Models

• Authors: Ankan Sur, Roberto Tejada Arevalo, Adam Burrows, Yi-Xian Chen

• Subjects: Subjects:
  Earth and Planetary Astrophysics (astro-ph.EP)

• Arxiv link: https://arxiv.org/abs/2510.08681

• Pdf link: https://arxiv.org/pdf/2510.08681

• Abstract
  We present a comprehensive comparison between legacy and modern evolutionary models for giant exoplanets, using our planetary evolution code, APPLE, to emulate and extend previous studies. Our analysis isolates and quantifies the impact of recent physical advances motivated by detailed modeling of Jupiter and Saturn, including updated hydrogen-helium and heavy-element equations of state, helium rain, "fuzzy" cores, and non-adiabatic, inhomogeneous envelopes, alongside improved atmospheric boundary conditions that incorporate ammonia cloud physics. We first examine the influence of each new physical ingredient individually, then construct combined baseline models for masses between 0.3 to 4 Jupiter masses to assess their collective effect on planetary structure and observable properties. We find that the adoption of modern equations of state and realistic heavy-element distributions leads to systematic, but sometimes subtle, differences (~5 to 10%) in radius evolution, while helium rain and the treatment of convection can significantly alter thermal histories and atmospheric compositions (by ~5 to 20%). These updated physical processes must be incorporated into the next-generation exoplanet evolutionary models to achieve physically consistent interpretations of planetary observations.

That's so Retro: The Gaia-Sausage-Enceladus Merger Trajectory as the Origin of the Chemical Abundance Bimodality in the Milky Way Disk

• Authors: James W. Johnson, Diane K. Feuillet, Ana Bonaca, Danielle de Brito Silva

• Subjects: Subjects:
  Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

• Arxiv link: https://arxiv.org/abs/2510.08688

• Pdf link: https://arxiv.org/pdf/2510.08688

• Abstract
  The Milky Way (MW) is thought to have experienced a $\sim$3:1 mass-ratio merger event near redshift $z\sim2$ with a significantly retrograde trajectory. This now-disrupted dwarf galaxy is commonly known as the Gaia-Sausage-Enceladus (GSE). In this paper, we investigate the impact of the GSE merger trajectory on metal abundances in the MW disk. We construct numerical models of Galactic chemical evolution (GCE) incorporating radial gas flows to account for angular momentum transport during the merger event. Unlike prograde trajectories, radial and retrograde mergers are generally accompanied by a major sinking event in which much of the interstellar medium falls toward the Galactic center. This effect leads to a net decrease in surface density across much of the disk. Ongoing Type Ia supernova explosions then drive a rapid decline in [$\alpha$/Fe] due to the lowered gas supply. Consequently, radial and retrograde trajectories increase (decrease) the number of low (high) [$\alpha$/Fe] stellar populations relative to prograde trajectories. If high [$\alpha$/Fe] stars form in sufficient numbers through other mechanisms, the effect of the retrograde trajectory can produce a bimodal [$\alpha$/Fe] distribution at fixed [Fe/H], as observed in the MW. In models dominated by low [$\alpha$/Fe] stellar populations, a bimodality does not arise because the retrograde trajectory cannot increase the number of high [$\alpha$/Fe] stars. More broadly, our results highlight the importance of gas dynamics in GCE models featuring major merger events.

The ExoGRAVITY survey: a K-band spectral library of giant exoplanet and brown dwarf companions

• Authors: J. Kammerer, T. O. Winterhalder, S. Lacour, T. Stolker, G.-D. Marleau, W. O. Balmer, A. F. Moore, L. Piscarreta, C. Toci, A. Mérand, M. Nowak, E. L. Rickman, L. Pueyo, N. Pourré, E. Nasedkin, J. J. Wang, G. Bourdarot, F. Eisenhauer, Th. Henning, R. Garcia Lopez, E.F. van Dishoeck, T. Forveille, J. D. Monnier, R. Abuter, A. Amorim, M. Benisty, J.-P. Berger, H. Beust, S. Blunt, A. Boccaletti, M. Bonnefoy, H. Bonnet, M. S. Bordoni, W. Brandner, F. Cantalloube, P. Caselli, W. Ceva, B. Charnay, G. Chauvin, A. Chavez, A. Chomez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Davies, R. Dembet, J. Dexter, A. Drescher, G. Duvert, A. Eckart, C. Fontanive, N. M. Förster Schreiber, P. Garcia, E. Gendron, R. Genzel, S. Gillessen, J. H. Girard, S. Grant, J. Hagelberg, X. Haubois, G. Heißel, S. Hinkley, S. Hippler, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, P. Kervella, L. Kreidberg, N. T. Kurtovic, A.-M. Lagrange, V. Lapeyrère, J.-B. Le Bouquin, D. Lutz, A.-L. Maire, F. Mang, E. C. Matthews, P. Mollière, C. Mordasini, D. Mouillet, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, D. C. Ribeiro, Z. Rustamkulov, D. Ségransan, J. Shangguan, T. Shimizu, M. Samland, D. Sing, J. Stadler, O. Straub, C. Straubmeier, E. Sturm

• Subjects: Subjects:
  Earth and Planetary Astrophysics (astro-ph.EP)

• Arxiv link: https://arxiv.org/abs/2510.08691

• Pdf link: https://arxiv.org/pdf/2510.08691

• Abstract
  Direct observations of exoplanet and brown dwarf companions with near-infrared interferometry, first enabled by the dual-field mode of VLTI/GRAVITY, provide unique measurements of the objects' orbital motion and atmospheric composition. Here, we compile a homogeneous library of all exoplanet and brown dwarf K-band spectra observed by GRAVITY thus far. We re-reduce all available GRAVITY dual-field high-contrast data and, where companions are detected, extract their ~2.0-2.4 $\mu$m K-band contrast spectra. We then derive stellar model atmospheres for all employed flux references that we use to convert the companion contrast into companion flux spectra. Solely from the resulting GRAVITY spectra, we extract spectral types, spectral indices, and bulk physical properties for all companions. Finally, and with the help of age constraints from the literature, we also derive isochronal masses for most companions using evolutionary models. The resulting library contains R ~ 500 GRAVITY spectra of 39 substellar companions from late M to late T spectral type, including the entire L-T transition. Throughout this transition, a shift from CO-dominated late M- and L-type dwarfs to CH4-dominated T-type dwarfs can be observed in the K-band. The GRAVITY spectra alone constrain the objects' bolometric luminosity to typically within $\pm$0.15 dex. The derived isochronal masses agree with dynamical masses from the literature where available, except for HD 4113 c for which we confirm its previously reported potential underluminosity. Medium resolution spectroscopy of substellar companions with GRAVITY provides insight into the carbon chemistry and the cloudiness of these objects' atmospheres. It also constrains these objects' bolometric luminosity which can yield measurements of their formation entropy if combined with dynamical masses, for instance from Gaia and GRAVITY astrometry.

The Sonora Substellar Atmosphere Models VI. Red Diamondback: Extending Diamondback with SPHINX for Brown Dwarf Early Evolution

• Authors: C. Evan Davis, Jonathan J. Fortney, Aishwarya Iyer, Sagnick Mukherjee, Caroline V. Morley, Mark S. Marley, Michael Line, Philip S. Muirhead

• Subjects: Subjects:
  Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2510.08694

• Pdf link: https://arxiv.org/pdf/2510.08694

• Abstract
  We extend the Sonora Diamondback brown dwarf evolution models to higher effective temperatures to treat the evolution of younger, higher mass objects. Due to an upper temperature limit of $T_\mathrm{eff}=$2400 K in the original Sonora Diamondback model grid, high mass objects ($M\geq$ 0.05 $M_\mathrm{\odot}=$ 52.4 $M_\mathrm{J}$) were limited to ages of $\gtrsim$ 100 Myr. To include the early evolution of brown dwarfs at $T_\mathrm{eff}>$ 2400 K, we use existing and new SPHINX cloud-free model atmosphere calculations of temperature structures of M-type atmospheres. These atmospheres range from $T_\mathrm{eff}$ 2000--4000 K, log($g$) 3.0--5.5, and metallicity [M/H] $-$0.5 to $+$0.5. This combination of Diamondback and SPHINX atmospheres, with a transition across $T_\mathrm{eff}$ 2000--2400 K, allows us to calculate evolution tracks, and infrared photometry and colors, for ages $>$ 1 Myr and masses from above the hydrogen burning minimum mass down to planetary masses. The Hayashi phase of massive brown dwarf evolution (ages $<$ 10--100 Myr) at low surface gravity leads to nearly constant $T_\mathrm{eff}$ values, at effective temperatures much lower than would be obtained from simply extrapolating backwards from evolution tracks at older ages.

Neutrino signal from the hadron-quark phase transition in the conversion of Neutron Stars into Quark Stars

• Authors: Yossef Zenati, Conrado Albertus Torres, Joseph Silk, M.Ángeles Pérez-García

• Subjects: Subjects:
  High Energy Astrophysical Phenomena (astro-ph.HE)

• Arxiv link: https://arxiv.org/abs/2510.08707

• Pdf link: https://arxiv.org/pdf/2510.08707

• Abstract
  We calculate in a 1D General Relativistic (GR) hydrodynamic simulation the neutrino luminosity in an astrophysical scenario where a neutron star (NS) displays a hadron-quark phase transition (HQPT) into a Quark Star (QS). Deconfinement is triggered once the central density exceeds a critical threshold above $\sim 3n_0$ being $n_0$, saturation density. We use descriptions based on DD2 and the MIT Bag model equations of state (EOSs). We account for neutrinos using a microphysics forward emission model including $e^-e^+$ annihilation, plasmon decay, nucleon (N) modified (or direct) Urca processes, and $NN$ bremsstrahlung, and, for the post transition, the quark direct Urca and an opacity-based leakage scheme with GR redshift. We find that the neutrino light curve generically develops a short $\simeq$10-50 ms, spectrally harder feature near deconfinement, appearing as either a prompt shoulder or a distinct secondary peak. Heavy lepton neutrinos result in a delayed peak with respect to the previous. We identify three diagnostics that are only mildly degenerate with hadronic uncertainties: (i) an enhanced peak-to-plateau ratio $R_{\rm pp}$ sourced by latent-heat release, (ii) a characteristic lag $\Delta t$ between the collapse rise and the HQPT feature that tracks the central density trajectory, and (iii) a flavor hardening $\Delta!\langle E_\nu\rangle$ driven by quark-matter phase space. After MSW flavor conversion, these signatures remain detectable with current experiments. For a Galactic event ($d\sim 10$ kpc), IceCube and Hyper-K should resolve the HQPT feature and distinguish it from both no transition NS collapse and canonical core-collapse supernova (CCSN) templates.

Low-Frequency Gravitational Waves in Three-Dimensional Core-Collapse Supernova Models

• Authors: Colter J. Richardson, Anthony Mezzacappa, Kya Schluterman, Haakon Andresen, Eric J. Lentz, Pedro Marronetti, Daniel Murphy, Michele Zanolin

• Subjects: Subjects:
  High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

• Arxiv link: https://arxiv.org/abs/2510.08764

• Pdf link: https://arxiv.org/pdf/2510.08764

• Abstract
  We discuss the low-frequency gravitational wave signals from three state-of-the-art three-dimensional core-collapse supernova models produced with the \textsc{Chimera} supernova code. We provide a detailed derivation of the gravitational wave signal sourced from the anisotropic emission of neutrinos and provide the total (fluid sourced and neutrino sourced) gravitational waves signal generated in our models. We discuss the templatablity of this low-frequency signal, which is useful for future work involving matched filtering for signal detection and parameter estimation.

Tides from the cloud can induce the fast disruption of star clusters and offer an explanation for Gaia strings

• Authors: Xiao-Tong Chen, Guang-Xing Li

• Subjects: Subjects:
  Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2510.08913

• Pdf link: https://arxiv.org/pdf/2510.08913

• Abstract
  Young stars form in clusters within molecular clouds, but older stars are evenly distributed across the galactic disk, necessitating an explanation for cluster dissolution. We analytically study tidal forces from cold molecular clouds as a key mechanism for accelerated cluster disruption. Cloud tides, caused by the gravitational pull of the parent cloud along the radial direction, arise from the spatial gradient of gravitational acceleration and drive cluster disruption. This mechanism activates after gas expulsion and remains effective until the cloud is disrupted by stellar feedback or the cluster moves away. Cloud tides act on gas-deprived clusters, causing exponential expansion on a tidal timescale of $t_{\rm tidal,ext} = \sqrt{3/(8\pi G\rho_{\rm mean})}$, where $\rho_{\rm mean}$ is the cloud's density at the cluster's location. With a duration of a few Myr, cloud tides can lead to a 10 times increase of the cluster size, producing bar-like elongated stellar aggregations resembling Gaia strings. These results establish cloud tides as a potentially important mechanism for star cluster disruption.

HST Confirms Sub-5 kpc Dual Quasar Pairs at Cosmic Noon

• Authors: Qian Wang, Xuheng Ding, John Silverman, J. Xavier Prochaska, Tommaso Treu, Hassen M. Yesuf, Masatoshi Imanishi, Nobunari Kashikawa, Issha Kayo, Kotaro Kohno, Kai Liao, Yoshiki Matsuoka, Michael A. Strauss, Shenli Tang

• Subjects: Subjects:
  Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2510.09059

• Pdf link: https://arxiv.org/pdf/2510.09059

• Abstract
  During cosmic noon ($z\sim1-3$), when both star formation and black hole growth peaked, galaxy mergers are predicted to trigger dual active galactic nuclei (AGN) that eventually coalesce as supermassive black hole (SMBH) binaries. However, observations of dual quasars with sub-5 kpc separations-the critical phase preceding final coalescence-have remained elusive due to angular resolution limitations. We present the discovery and confirmation of two sub-arcsecond dual quasars at $z>1$, selected from 59,025 SDSS quasars, which fall within the footprint of the Hyper Suprime-Cam Survey. Using high-resolution Hubble Space Telescope (HST) imaging and slitless spectroscopy, we confirmed SDSS J1625+4309 ($z=1.647$, separation 0.55"/4.7 kpc) and SDSS J0229$-$0514 ($z=3.174$, separation 0.42"/3.2 kpc), probing the sub-5 kpc separation regime. Through novel combination of WFC3/IR direct imaging (F140W) and grism spectroscopy (G141), we resolve both components morphologically and spectroscopically confirm their dual nature via detection of H$\beta$+[OIII] and MgII emission lines in each nucleus. Two-dimensional image decomposition reveals distinct host galaxy morphologies: J1625+4309 shows an extended, disturbed structure ($R_e$=4.7 kpc) indicative of an ongoing major merger, while J0229$-$0514 exhibits a compact host ($R_e$=1.4 kpc) suggesting an advanced coalescence stage. Black hole mass estimates based on virial relations yield M${\mathrm{BH}} \sim 10^{8.1}-10^{8.7} M\odot$ with line-of-sight velocity offsets of $(0.7\pm0.1)\times10^{3}$ km s$^{-1}$ and $(1.0\pm0.2)\times10^{3}$ km s$^{-1}$, respectively. These confirmations directly constrain the frequency and properties of close dual quasars, opening new avenues for studying SMBH mergers at cosmic noon.

The Low-Frequency Spectra of Radio Pulsars

• Authors: Ting Yu, Zhongli Zhang, Hongyu Gong, Zhigang Wen

• Subjects: Subjects:
  Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2510.09091

• Pdf link: https://arxiv.org/pdf/2510.09091

• Abstract
  Low-frequency spectral studies of radio pulsars represent a key method for uncovering their emission mechanisms, magnetospheric structure, and signal interactions with the surrounding interstellar medium (ISM). In recent years, more next-generation low-frequency radio telescopes (e.g., LOFAR, LWA and MWA) have enriched the observational window below 350 MHz, enabling more detailed explorations of the ISM effects, such as absorption and scattering, resulting in diverse spectral behaviors observed across different pulsars. This paper reviews the morphology of pulsar radio spectra, advances in spectral modeling, and the key physical processes governing the low-frequency emission. Looking ahead, next-generation instruments such as SKA-Low - with their unprecedented sensitivity - are expected to resolve outstanding questions in pulsar emission processes, offering insights into the extreme physical regimes governing these exotic objects.

Identification of molecular line emission using Convolutional Neural Networks

• Authors: Nina Kessler, Timea Csengeri, David Cornu, Sylvain Bontemps, Laure Bouscasse

• Subjects: Subjects:
  Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)

• Arxiv link: https://arxiv.org/abs/2510.09119

• Pdf link: https://arxiv.org/pdf/2510.09119

• Abstract
  Complex organic molecules (COMs) are observed to be abundant in various astrophysical environments, in particular toward star forming regions they are observed both toward protostellar envelopes as well as shocked regions. Emission spectrum especially of heavier COMs may consists of up to hundreds of lines, where line blending hinders the analysis. However, identifying the molecular composition of the gas leading to the observed millimeter spectra is the first step toward a quantitative analysis. We develop a new method based on supervised machine learning to recognize spectroscopic features of the rotational spectrum of molecules in the 3mm atmospheric transmission band for a list of species including COMs with the aim to obtain a detection probability. We used local thermodynamic equilibrium (LTE) modeling to build a large set of synthetic spectra of 20 molecular species including COMs with a range of physical conditions typical for star forming regions. We successfully designed and trained a Convolutional Neural Network (CNN) that provides detection probabilities of individual species in the spectra. We demonstrate that the produced CNN-model has a robust performance to detect spectroscopic signatures from these species in synthetic spectra. We evaluate its ability to detect molecules according to the noise level, frequency coverage, and line-richness, and also test its performance for incomplete frequency coverage with high detection probabilities for the tested parameter space, and no false predictions. Ultimately, we apply the CNN-model to obtain predictions on observational data from the literature toward line-rich hot-core like sources, where detection probabilities remain reasonable with no false detection. We prove the use of CNNs facilitating the analysis of complex millimeter spectra both on synthetic spectra as well as first tests on observational data.

JWST Observations of SN 2024ggi II: NIRSpec Spectroscopy and CO Modeling at 285 and 385 Days Past the Explosion

• Authors: T. Mera, C. Ashall, P. Hoeflich, K. Medler, M. Shahbandeh, C. R. Burns, E. Baron, J. M. DerKacy, E. Fereidouni, C. M. Pfeffer, S. Shiber, P. J. Brown, A. Burrow, D. .A. Coulter, M. Engesser, L. Ferrari, G. Folatelli, O. Fox, L. Galbany, M. Guolo, J. T. Hinkle, W. B. Hoogendam, E. Y. Hsiao, M E. Huber, T. de Jaeger, D. O. Jones, S. Kumar, J. Lu, P. A. Mazzali, N. Morrell, M. M. Phillips, A. Rest, N. B. Suntzeff, B. J. Shappee, Jennifer Shi, M. D. Stritzinger, L. Strolger, T. Temim, S. Tinyanont, M. Tucker, L. Wang, Q. Wang, Y. Yang

• Subjects: Subjects:
  Solar and Stellar Astrophysics (astro-ph.SR)

• Arxiv link: https://arxiv.org/abs/2510.09600

• Pdf link: https://arxiv.org/pdf/2510.09600

• Abstract
  We present James Webb Space Telescope (JWST) NIRSpec 1.7--5.5 micron observations of SN~2024ggi at +285.51 and +385.27 days post-explosion. The late-time nebular spectra are dominated by emission lines from various ionization states of H, Ca, Ar, C, Mg, Ni, Co, and Fe. We also detect strong CO emission in both the first overtone and fundamental vibrational bands. Most atomic features exhibit asymmetric line profiles, indicating an aspherical explosion. Using observed fluxes combined with non-LTE radiative-transfer simulations, we develop a data-driven method that resolves the complex molecular-emission region, constrains its 3D structure, and reproduces high-fidelity spectral profiles. We find that, CO is mostly formed prior to +285d past explosion. The subsequent evolution is dominated by the evaporation of CO with CO mass varying from M(CO) of 8.7E-3 to 1.3E-3 Mo, and with instabilities growing from almost homogeneous to highly clumped (density contrast f_c of 1.2 to 2). The minimum velocity of CO only slightly decreases between epochs (v_1 of 1200 and 1100 km/sec), with the reference temperature dropping from T_1 of 2400 and 1900K.

by olozhika (Xing Yuchen).

2025-10-14