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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.GAgr-qc

A Graph Attention Network Framework for Simultaneous Prediction of Galaxy and Dark Matter Halo Properties in GAMA DR4

Sandeep Aashish, Abhay V Hegde, Aditya Prakash Gupta, Ashmit Verma, Md Saif, Nishanth Kumaran, Shivang Rayat

We develop a graph-based deep learning model, GAMANet, to predict galaxy and halo properties using the GAMA DR4 dataset. Multiple catalogues are combined to construct a unified sample of 19,469 galaxies and derive a set of photometric, spectroscopic, morphological, and environmental features. The galaxy sample is represented as a graph, with galaxies as nodes and physically motivated connections based on spatial proximity and group membership as edges. A Graph Attention Network with GATv2 layers…

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astro-ph.IM

Very Long Baseline Interferometry with the SKA Observatory

J. F. Radcliffe, J. Yang, Z. Paragi, O. Bayandina, C. Reynolds, C. García-Miró, T. An, M. Abada-Simon et al.

Very Long Baseline Interferometry (VLBI) is a fundamental technique that combines signals from telescopes separated by thousands of kilometres to obtain some of the highest-resolution images in astronomy. The Square Kilometre Array Observatory (SKAO) will provide sensitive elements to current VLBI arrays, enabling deep VLBI observations (including the first low-frequency VLBI capability in the Southern Hemisphere). This summary chapter outlines the science that the SKAO, when participating in a…

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astro-ph.GA

The Role of the Cosmic Web in Galaxy Evolution Across 0.4<z<4

Sina Taamoli, Bahram Mobasher, Hossein Hatamnia, Nima Chartab, John R. Weaver, Ghassem Gozaliasl, Anton M. Koekemoer, Caitlin M. Casey et al.

We investigate the dependence of stellar mass and star formation activity on the topology of hosting large-scale structures using mass-complete galaxy samples in four redshift bins spanning from z = 0.4 to z = 4 using the COSMOS2020 catalog. Cosmic web components (clusters, filaments, and field) are identified by applying the Multiscale Morphology Filter to galaxy density maps, and group memberships (central, satellite, isolated) are assigned to each galaxy by the Friends of Friends (FoF) algori…

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astro-ph.EP

Hubble Space Telescope Observations of Active Asteroid (101955) Bennu

David jewitt, Max Mutchler, Yoonyoung Kim

Measurements from NASA's OSIRIS-REx spacecraft revealed (101955) Bennu as a member of the active asteroid class. These objects exhibit transient, comet-like activity, commonly producing particle trails best observed from a vantage point close to the projected orbit plane. Accordingly, we obtained deep, high resolution observations of Bennu at orbit plane crossing in 2023, using the Hubble Space Telescope. We find no evidence for ejected material, and place model-dependent limits to the mass loss…

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astro-ph.GA

Radiation pressure powers quasar broad absorption line winds but fails to drive galaxy feedback

Braden Seefeldt-Gail, Lluís Mas-Ribas, Norman Murray

Most cosmological simulations invoke quasar-driven winds as the primary mechanism quenching star formation in massive galaxies, assuming wind momentum flux approaches the radiation-pressure maximum, $L/c$. Using 81,388 broad absorption line troughs from the SDSS-IV DR16 quasar catalog and detailed mock trough spectra, we detect line locking, a spectral signature of radiation-pressure-driven outflows, in 60 to 70 percent of troughs, demonstrating that radiative line driving dominates wind acceler…

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astro-ph.EPastro-ph.IM

Discovery of 2 km ultra-fast rotating asteroid in Rubin DP2 catalog via varying Fourier order method

Dmitrii E. Vavilov, Siegfried Eggl, Sarah Greenstreet

Time-resolved photometry from large surveys can yield rotation periods for huge numbers of asteroids, but only if the reliability of each period is assessed automatically, since sparse and irregular sampling produces many false periodogram minima. We present an improved method that determines asteroid rotation periods with a Fourier series whose order is chosen for each object individually. This has substantial advantages over lower order methods, especially when unique solutions for the spin pe…

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astro-ph.GA

Stirred, not shaken: Dislodging $ω$ Centauri from the Sausage galaxy through bar resonances

Axel Mannu, Chervin F. P. Laporte, Matthew D. A. Orkney, Yassin Rany Khalil, Benoit Famaey

We test the idea proposed by Laporte \& Orkney that $ω$ Centauri ($ω$Cen) is the central nuclear star cluster of the Gaia-Sausage-Enceladus galaxy (GSE) which got dislodged by the bar. We run a series of simulations in time-evolving bar potentials with present-day pattern speeds within Portail et al's $Ω_{b}=39\pm3.5\,\rm{km\,s^{-1}\,kpc^{-1}}$ and rate of slow-down $\dotΩ_{\rm b}= 4.5 \pm 1.4 \,\rm{km \,s^{-1}\,kpc^{-1}\, Gyr^{-1}}$ to study how bar resonances modulate the angular momentum and…

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physics.space-phcond-mat.mtrl-sci

Data-driven prediction of atomic-oxygen erosion yield in polymers from bulk physical properties

Youngwoo Choi, Doeun Koo, Seungbum Hong, Hyun Jung Kim

Atomic oxygen (AO) erodes polymer surfaces in low Earth orbit, but durability data are limited. We evaluated a regression ensemble trained on 37 MISSE-2 polymers using eight selected bulk properties and five elemental-composition ratios. Its archived leave-one-out R^2(log) was 0.768; this estimate is conditional on feature selection using the complete training table. For nine post-MISSE-2 polymers, the ensemble gave R^2(log) = -0.037 and all predictions were within a factor of two. The training…

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astro-ph.GAastro-ph.SR

Barium and europium abundances from the Gaia-ESO Survey using The Cannon

Pradosh Barun Das, Francesca Primas, Gayandhi De Silva, Guillaume Guiglion, Daniel B. Zucker, Melissa Ness

Neutron-capture element abundances encode the time-dependent interplay between slow (s-) and rapid (r-) nucleosynthetic processes and provide critical constraints on Galactic chemical evolution. In particular, barium and europium provide important tracers of s-process and r-process nucleosynthetic enrichment, respectively. Large spectroscopic surveys enable robust statistical studies of these elements; however, determining reliable elemental abundances at intermediate spectral resolution remains…

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astro-ph.IM

The First Decade of Breakthrough Listen

David H. E. MacMahon, Daniel J Czech

Breakthrough Listen (BL), launched in July 2015 with a 10-year, \$100M commitment from the Breakthrough Prize Foundation, is the most comprehensive search for technosignatures ever conducted. This paper reviews the program's first decade from the facilities and instrumentation perspective: the digital backends and data recorders, the signal-processing pipelines, the data archive, and the observatory partnerships that made the science possible. We organize the decade into three architectural eras…

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astro-ph.SR

High-Angular-Resolution Survey of Stars within 18 pc of the Sun: Part I

F. Carolina Rojas-Galindo, Valeri G. Orlov, Rene A. Mendez, Wolfgang Brandner

We present the rationale, design, methodology, and observational facilities of a high-angular-resolution imaging survey of stars within 18~pc of the Sun. Our comprehensive sample consists of 2047 stars compiled from \textit{Gaia} eDR3 and complementary catalogs. The main goal is to observe as many stars from this sample as possible using high-angular-resolution techniques, considering their inherent limitations, to perform astrometry of known binary systems and determine detection limits for sec…

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astro-ph.SR

High-Angular-Resolution Survey of Stars within 18 pc of the Sun: Part I

F. Carolina Rojas-Galindo, Valeri G. Orlov, Rene A. Mendez, Wolfgang Brandner

We present the rationale, design, methodology, and observational facilities of a high-angular-resolution imaging survey of stars within 18~pc of the Sun. Our comprehensive sample consists of 2047 stars compiled from Gaia eDR3 and complementary catalogs. The main goal is to observe as many stars from this sample as possible using high-angular-resolution techniques, considering their inherent limitations, to perform astrometry of known binary systems and determine detection limits for secondary co…

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astro-ph.GA

The Rogue One: A Dark Matter-Dominated Dwarf in the Trail of Dark Matter-Deficient Galaxies

Daniel Vaz, Arsen Levitskiy, Duncan Forbes, Aaron J. Romanowsky, Jonah Gannon, Jean P. Brodie, Yimeng Tang, Kenji Bekki et al.

We present the first measurement of the stellar velocity dispersion of LEDA 4014647, a compact dwarf galaxy spatially aligned with the NGC 1052 trail, a linear chain of dark matter-deficient galaxies (DMDGs) proposed to have formed in a single high-speed dwarf$-$dwarf collision $\sim 8$ Gyr ago. Using integral-field spectroscopy obtained with the Keck Cosmic Web Imager (KCWI), we measure a stellar velocity dispersion of $σ= 15.8 \pm 2.0$ km s$^{-1}$ within the half-light radius ($R_\mathrm{e}$).…

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astro-ph.GAastro-ph.SR

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) III. CH$_3$OH isotopic fractionation in the low-mass protostar BHR71-IRS1

A. Coutens, F. Cruz-Sáenz de Miera, J. K. Jørgensen, M. N. Drozdovskaya, J. -E. Lee, A. L. Plunkett, D. Harsono, S. Maret et al.

[Abridged] Methanol is a complex organic molecule detected in both ice and gas toward star-forming regions. Due to its high abundance, its rarer isotopologues, including the deuterated ones, are also commonly detected. Our aim is to determine the column density and deuterium fractionation of methanol in the low-mass protostar BHR71-IRS1. We analyzed data from a large spectral survey of BHR71-IRS1 carried out as part of the ALMA Large Program Complex Organic Molecules in Protostars with ALMA Spec…

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astro-ph.GA

Life in the Cosmic Neighbourhood: Galactic Habitable Zones in the EAGLE Simulations

Luke A. Barnes, Geraint F. Lewis, Jaime Salcido, Pascal Elahi, Miroslav D. Filipovic, Richard G. Bower

When and where is life most likely to form in the universe? We use the EAGLE cosmological hydrodynamical simulations to investigate the prevalence and properties of life-friendly cosmic environments on galactic scales. Our model for the occurrence of observers depends on main-sequence stars, the production and distribution of metals, and the formation of habitable planets. We also take into account five potentially life-extinguishing processes: core-collapse supernovae, Type Ia supernovae, star-…

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astro-ph.HEastro-ph.IM

Adaptive proposals for nonparametric equation-of-state inference with RIFT: iterative Gaussian-process refinement in a compressed sequence representation

R. O'Shaughnessy, Z. Zhu

Nonparametric equation-of-state (EOS) inference evaluates the likelihood on a finite ensemble drawn from a prescribed functional prior. Reweighting that ensemble suffices for the binary neutron stars detected so far, and loses effective sample size only once the likelihood concentrates --- which needs third-generation catalogues, or extra electromagnetic and nuclear-theory information folded into the same target. We develop and validate an adaptive-proposal procedure that leaves the base prior f…

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astro-ph.SR

Axial-Dipole and Equatorial-Dipole Coronal Holes: Congruent Magnetic Geometry, Divergent Evolution

Olga A. Panasenco, Yi-Ming Wang, Samuel T. Badman, Adam J. Finley, Yeimy J. Rivera

While the Sun's polar fields reverse, the axial dipole is weak and low-latitude coronal holes are common. Equatorial-dipole coronal holes (EDCHs) appear when the equatorial dipole is strong, forming at its magnetic poles, similar to the axial-dipole coronal holes (ADCHs) of minimum. Not every low-latitude hole qualifies: the 2024 maximum was quadrupole-led. Parker Solar Probe found fast wind from an EDCH deeply sub-Alfvénic at $9.9\,R_\odot$, at only $60\%$ of an asymptotic speed matching polar…

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astro-ph.GA

BRAHMa: Bar Recognition And Hatching using Machine learning -- a framework for oriented bounding box detection of galactic bars

Rajit Shrivastava, Narendra Nath Patra, Keerthi K

Galactic bars are fundamental components in studies of dark matter, galaxy evolution, and secular dynamics. However, current methods for measuring bar properties suffer from significant limitations. Manual and crowdsourced catalogs are not scalable to next-generation surveys, while recent machine learning (ML) approaches based on pixel-wise segmentation are computationally intensive and require complex post-processing to extract physical parameters. In this paper, we introduce BRAHMa (Bar Recogn…

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astro-ph.GA

BRAHMa: Bar Recognition And Hatching using Machine learning -- a framework for oriented bounding box detection of galactic bars

Rajit Shrivastava, Narendra Nath Patra, Keerthi K

Galactic bars are fundamental components in studies of dark matter, galaxy evolution, and secular dynamics. However, current methods for measuring bar properties suffer from significant limitations. Manual and crowdsourced catalogs are not scalable to next-generation surveys, while recent machine learning (ML) approaches based on pixel-wise segmentation are computationally intensive and require complex post-processing to extract physical parameters. In this paper, we introduce BRAHMa (Bar Recogn…

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astro-ph.EP

Tracing the main belt origins of S-complex near-Earth objects: From space mission targets to meteorite sources

P. N. Simon, P. Vernazza, M. Marsset, M. Brož, R. P. Binzel, F. DeMeo, C. A. Thomas, L. Jorda et al.

Context. Space missions to near-Earth objects (NEOs) provide unique opportunities to study and characterise their physical and compositional properties. Interpreting these results requires knowledge of their provenance, i.e. their source family in the main asteroid belt. Aims. We aim to identify the family sources of six S-complex NEOs visited or soon to be visited by space missions, and to investigate the size-dependent orbital behaviour of the broader S-complex NEO population using the MITHNEO…

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astro-ph.GAhep-ph

Occam's Razor and a Three-Family Ultralight Fermionic Dark Matter Model

Fabian Hernandez-Gutierrez, Juan Barranco

Inspired by the three generations in the Standard Model, we propose that dark matter particles are simply three non-interacting ultralight fermions. This model is tested at galactic scales with the SPARC catalog of rotational velocity curves. This is done by modeling the dark matter halo as the self-gravitating configuration of three gravitationally coupled fermion species. This configuration is capable of forming more complex rotational curves which gives it flexibility to describe more complex…

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astro-ph.IMastro-ph.HEastro-ph.SR

SPECULATE: A synthetic spectral library, emulator and fitting package for accretion disc winds -- Infrastructure and application to CVs

Austen G. W. Wallis, Christian Knigge, James H. Matthews, Knox S. Long, Madeleine-Mai Ward, Stuart A. Sim, Adam B. Hill, Amin Mosallanezhad et al.

Disc winds are critical components of accreting astrophysical systems and their observations can yield a wide variety of spectral line profiles. Yet, inferring disc wind parameters remains challenging: the underlying parameter spaces are high-dimensional and degenerate, while the radiative-transfer simulations are imperfect and computationally expensive. This paper tackles bridging this gap. Here, we present 'Speculate', an open-source framework for rapidly emulating and fitting observations wit…

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astro-ph.GA

The universal thickness of mid-infrared bubbles

Michael M. Schulreich, A. Beate C. Patzer

Several hundred ring-like structures seen at $8μ$m in the Spitzer GLIMPSE surveys share a uniform morphology: the shell thickness $ΔR$ is a nearly constant fraction of the outer radius $R$, $ΔR/R\sim0.3$, across a factor of 40 in size and all exciting spectral types. This invariance is unexplained. We ask what sets this thickness and whether its near-constancy is physical or a measurement artifact. We derive analytic constraints on the location, temperature, and heating of the emitting grains, a…

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astro-ph.IM

A Classifier Framework for ALMA Bandpass Calibration Anomalies

Ci Xue, Brian S. Mason, Gazi A. Rakib, Tristan Ashton, Jeff M. Phillips, Ignacio Toledo, Ryan A. Loomis, Ilsang Yoon et al.

Bandpass calibration corrects instrumental responses across observing frequencies in interferometric radio observations, so the measured calibration solutions inherently contain spectral variation that varies with instrumental configurations and noise conditions. However, some signals contain anomalies, which if not caught can lead to poorly constructed science products. Observatory pipelines often use scalar metrics with individual, linear decision boundaries. Constructing a simple parametric m…

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astro-ph.HEastro-ph.GA

A spatially resolved view of Fast Radio Burst host metallicities with Integral-field Spectroscopy

Sunil Simha, Hsiao-Wen Chen, Wen-fai Fong, Sarah Hughes, Yuxin Dong, J. Xavier Prochaska, Nicolas Tejos, Tarraneh Eftekhari et al.

Magnetar sources are the leading theory for Fast Radio Burst (FRB) progenitors. If magnetars are indeed the dominant sources, we may thus expect any metallicity preference for magnetar formation to be reflected in the FRB site in host galaxies. Here, we leverage Integral Field Unit (IFU) spectroscopy to spatially resolve gas-phase metallicity distribution in five FRB host galaxies: FRB 20240210A, FRB 20240312D, FRB 20250227A, FRB 20211127I, and FRB 20250316A, at $z < 0.05$, including the FRB sit…

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astro-ph.HE

Investigating X-ray Emission from Radio-detected Broad- and Narrow-line Seyfert 1 Galaxies

Minhua Zhou, Minfeng Gu, Lei Xu, Mai Liao, ZhengXue Chang

Context: This paper presents a study of the X-ray emission for a sample of radio-detected (RD-) broad- and narrow-line Seyfert 1 galaxies (NLS1s and BLS1s). Aims: To investigate the X-ray emission properties of early-stage accretion activity or early jets in NLS1s. Methods: By fitting XMM-Newton X-ray spectra and combining with multi-band data from SDSS and FIRST, we conducted a statistical comparative study on the X-ray emission and multi-band correlations of NLS1s and BLS1s. Results: NLS1s and…

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astro-ph.GA

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) VII. First interstellar detection of fully deuterated methanol

A. Belloche, S. Spezzano, A. Coutens, M. N. Drozdovskaya, J. K. Jørgensen, J. -E. Lee, A. L. Plunkett, D. Harsono et al.

There have been no robust identifications of fully deuterated methanol, CD3OD, in the interstellar medium (ISM) to date. Our goal is continue the search for CD3OD in star-forming regions to determine the deuteration pattern of methanol and set constraints on the deuteration process. We used a sensitive imaging spectral survey of the protostellar system IRAS4A in the NGC1333 molecular cloud performed as part of the large program carried out with the Atacama Large Millimeter/submillimeter Array (A…

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astro-ph.GA

Multiple H I 21-cm absorbers towards blazar PKS 1158+007

Abhisek Mohapatra, R. Srianand, R. Dutta

We report an interesting line of sight towards the blazar PKS 1158+007 (J1201+0028) ($z_{\rm em}$ = 1.369), revealing the rare detection of two intervening HI 21-cm absorption systems within a narrow redshift interval ($Δz \sim 0.04$) using the MeerKAT radio telescope. The stronger absorber at $z_{\rm abs}$ $=0.5653$ ($\intτdv = 1.31\pm0.04$ \kms) is associated with a strong MgII $\lambda2796$ system seen in the Sloan Digital Sky Survey (SDSS) and Dark Energy Spectroscopic Instrument (DESI) spec…

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astro-ph.HEastro-ph.IM

Chana: A GPU-Accelerated AMR GRRMHD Code

Tianshu Wang

This paper presents Chana, a GPU-accelerated, block-structured adaptive-mesh code for general relativistic magnetohydrodynamics, multigroup M1 neutrino transport, and dynamical spacetime evolution using the Z4c formulation. Each physical module uses independently selected spatial discretizations and ghost-zone widths to balance accuracy and computational cost. Stiff radiation-matter interactions are treated implicitly, with Jacobians calculated analytically from the chain-rules. The code is writ…

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astro-ph.HEnucl-th

Radial Modes of Hot Neutrino-Trapped Hybrid Stars

Peter B. Rau, Andrea Sabatucci, Armen Sedrakian

We study the fundamental radial oscillation mode of hot hadronic and hybrid stars under conditions relevant to proto-neutron stars and neutron-star merger remnants. The stellar backgrounds are constructed from finite-temperature equations of state with a covariant density functional for hadronic matter and three-flavor 2SC quark matter at high density. We consider two isentropic configurations in both neutrino-transparent matter and with trapped electron neutrinos at fixed electron-lepton fracti…

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