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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.GA

Extending the Stellar-to-Halo Mass Relation to Dwarf Galaxies with DESI DR1

Z. Shao, Y. Zu, A. Salcedo, Y. Lin, Z. Chen, X. Xu, J. Hua, Z. Zhai et al.

Constraining the dark matter halos of the smallest galaxies offers fundamental insights into the nature of dark matter and stellar feedback. Using the Dark Energy Spectroscopic Instrument (DESI) Data Release 1, we infer the stellar-to-halo mass relation (SHMR) down to the dwarf scale ($M_\star < 10^9\,M_\odot$), without extrapolation from the higher mass range. Leveraging the unprecedented depth of the DESI Bright Galaxy Survey at $0.01 < z < 0.2$, we construct 12 samples spanning nearly four or…

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astro-ph.GAastro-ph.CO

H I Absorbers as Beacons of Hidden Structure at $z \sim 3$: Multi-Component, Metal-Rich Absorption System near a Protocluster

Kentaro Koretomo, Nobunari Kashikawa, Toru Misawa, Jun Toshikawa, Yoshihiro Takeda, Hisakazu Uchiyama, Junya Arita, Shunta Shimizu et al.

H I gas traces the large-scale structure and provides the primary fuel for star formation. High-$z$ protoclusters are ideal laboratories to study how H I gas is accreted and consumed during the formation of the most massive structures in the Universe. However, much remains unknown about the distribution and physical state of their H I gas. We examine a rare configuration in which a protocluster candidate is located in front of a quasar at $z=3.09$. Our spectroscopic campaign confirms a protoclus…

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gr-qcastro-ph.HE

Waveform models for the gravitational-wave memory effect: III. Phenomenological frequency-domain model for nonspinning binaries

Arwa Elhashash, David A. Nichols

We present a phenomenological frequency-domain model for the gravitational-wave (GW) memory signal from nonspinning binary-black-hole mergers on quasicircular orbits. We develop separate amplitude and phase models for the dominant $(l,m)=(2,0)$ spherical-harmonic mode of the GW memory signal. The amplitude and phase models are built from superpositions of elementary and transcendental functions, which can be evaluated efficiently. Both portions of the model are calibrated against a numerical-rel…

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astro-ph.GAastro-ph.CO

Widespread Inflows Reveal Baryonic Cycling in Star-forming and Quiescent Galaxies

Hassen M. Yesuf, Ravi Joshi, Yuxuan Zou, Feng Yuan, Luis C. Ho, Lin Lin, Lei Hao, Shiyin Shen et al.

Cool-gas inflows, required to sustain star formation, have been fundamental in simulations yet remained observationally elusive. Using DESI spectroscopy of ~30,000 galaxies, we identify coherent inflowing gas (~100 km/s) in 20-50% of the sample, yielding a population-level census of gas flows. We uncover a striking inversion: inflows are detected in quiescent galaxies, whereas star-forming systems are dominated by gravitationally bound outflows. At fixed age, galaxies with inflows, outflows, or…

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astro-ph.GA

Recovering Ionizing Photon Escape and Galaxy Scaling Relations in the LzLCS via Si II and C II Absorption Lines and Mock Spectra from a Radiation-Hydrodynamic Simulation

John Trevino, Simon Gazagnes, Danielle A. Berg, Kaelee S. Parker, Valentin Mauerhofer, Jeremy Blaizot, Anne Verhamme, Sophia R. Flury et al.

In this work, we use a radiation-hydrodynamic simulation of a single $\sim10^9M_{\odot}$ virtual galaxy to study Si II and C II line profiles seen in stacked HST/COS spectra of 58 galaxies from the LzLCS+ sample. We compare stacks across three mass bins ($M_{\star} \leq 10^8M_{\odot}$, $10^8$-$10^9M_{\odot}$, and $M_{\star} \geq 10^9M_{\odot}$) and three stacking methods (mean, median, and weighted average) to a library of 22,500 mock spectra. We investigate whether the simulation can accurately…

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astro-ph.SR

Improvements to Asteroseismic Fitting of White Dwarfs in the Gaia Era

Andrew H. Dublin, Keaton J. Bell, Agnès Bischoff-Kim

White dwarf asteroseismology aims to constrain the interior structures of pulsating white dwarf stars by fitting observed pulsation periods to those computed for stellar models. However, there remain several obstacles for achieving reliable results with the model grid-fitting approach. We simulate data for a parameter recovery experiment in one and two dimensions (mass and effective temperature) to demonstrate improved methodologies that address challenges for characterizing degenerate asterosei…

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astro-ph.GAastro-ph.HE

AGN-DB: A Unified Multi-Wavelength Database of Active Galactic Nuclei

Alessandro Peca, Nico Cappelluti, C. Megan Urry, Zhongtian Hu, Jerry R. Bonnell, Jack McKeown, Giulia Cerini, Xulei Sun et al.

We present the Active Galactic Nuclei Database (AGN-DB), a comprehensive, multi-wavelength catalog compiled from more than 100 publicly available AGN catalogs and samples released by the end of 2025, spanning radio to $γ$-ray wavelengths. The database contains approximately 8.1 million unique sources, approximately 7.8 million of which remain after flagging stellar contaminants, and approximately 6.8 million of these are classified as AGN. Source cross-matching across catalogs is performed using…

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astro-ph.EP

Composition gradients in sub-Neptunes: K2-18 b and TOI-270 d as case studies

Luca Morf, Ravit Helled

Structure models of sub-Neptunes commonly assume purely adiabatic interiors with distinct layers of homogeneous composition. We assess how allowing for more complex interiors with composition gradients affects the inferred internal structure and bulk compositions of the sub-Neptunes K2-18 b and TOI-270 d. We compare purely adiabatic models with distinct layers against models that include composition gradients and stable non-convective regions. We present solutions that are consistent with the ob…

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astro-ph.GA

Resolved Dust-Gas-Metallicity relations in nearby spiral galaxies

Vidhi Tailor, Viviana Casasola, Francesco Calura, Francesca Pozzi, Jacopo Fritz, Maritza Lara-López, Marco Palla, Simone Bianchi et al.

Context: Understanding the interstellar medium (ISM) requires high-resolution, multi-component mapping to capture its complex physical structure. Nearby spiral galaxies, with their abundant and diverse ISM, provide an ideal laboratory for such a comprehensive analysis at sub-galactic scales. Aims: We investigate dust-to-gas (DGR) and dust-to-metal (DMR) ratios as a functions of gas-phase metallicity (Z), on spatial scales ranging from 0.6 to 2.3 kpc, in a sample of 10 nearby spiral galaxies, spa…

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astro-ph.HEastro-ph.GA

A Kinematic Measurement of the Effective Viscosity of the Intracluster Medium: The Cold Front of A3667 Seen by XRISM

Yutaka Fujita, Yuki Omiya

Constraints on the effective viscosity of the intracluster medium (ICM) come almost exclusively from imaging: the power spectrum of X-ray surface brightness fluctuations, and the morphology of Kelvin-Helmholtz rolls at cold fronts. Both indicate a viscosity below the isotropic Spitzer value. XRISM/Resolve opens a complementary, purely kinematic route, in which the viscosity is inferred from the thickness of the viscous shear layer that develops at a sliding contact discontinuity. We apply it to…

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astro-ph.GAastro-ph.HE

Super-Eddington Accretion and Early-Stage Feedback in Ton S180

Pierpaolo Condò, Giacomo Venturi, Eleonora Parlanti, Marco Berton, Enrico Congiu, Alessia Tortosa, Stefano Carniani, Francesco Tombesi et al.

Narrow-line Seyfert 1 (NLSy1) galaxies are key laboratories for studying rapid supermassive black hole (SMBH) growth and active galactic nucleus (AGN) feedback at high accretion rates. We investigate the nearby NLSy1 Ton S180 with VLT-MUSE optical integral field spectroscopy to connect its nuclear accretion properties with the spatially resolved ionized gas and host-galaxy kinematics. We modeled the unresolved nuclear spectrum and applied a custom point spread function subtraction to recover the…

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astro-ph.IMastro-ph.CO

ALPACA I: Controlling source and PSF systematics in JWST time-delay cosmography with differentiable lens modeling

Hrvoje Krizic, Martin Millon, Aymeric Galan, Sydney Erickson, Phil Marshall

Time-delay cosmography provides an independent probe of the Hubble constant ($H_0$), but exploiting the high-resolution imaging of the James Webb Space Telescope (JWST) requires strong-lens models that capture complex source-galaxy morphologies and the point spread function (PSF) with high fidelity. Flexible source and joint PSF reconstruction are computationally expensive, motivating more rigid parameterizations that can bias the inferred time-delay distance $D_{Δt}$. We present ALPACA, a semi-…

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astro-ph.GA

JWST/NIRSpec Reveals Diverse Nuclear Environments in Dwarf Galaxies Hosting AGN

Thomas Bohn, Archana Aravindan, Gabriela Canalizo, Aditya Togi, Shobita Satyapal, Tohru Nagao, Matthew Malkan, Thomas S. Y. Lai et al.

Dwarf galaxies, in the $Λ$CDM framework, are expected to dominate the galaxy number density at all redshifts. As such, studying AGN in these systems, including characterizing their local environments and emission properties, is essential in obtaining a comprehensive view of the AGN population and their influence on their host galaxy. To this end, we present JWST/NIRSpec IFU observations of four dwarf galaxies (M$_\star<$10$^{9.5}\;$M$_\odot$) with evidence of AGN activity. Utilizing the improvem…

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astro-ph.SRastro-ph.GA

The DESI Data Release 1 white dwarf catalogue

Andrew Swan, Boris T. Gänsicke, Paula Izquierdo, Detlev Koester, Christopher J. Manser, Laura K. Rogers, Siyi Xu, J. Aguilar et al.

The Dark Energy Spectroscopic Instrument is conducting a redshift survey, mapping the universe in three dimensions to measure the history of cosmic expansion. As well as extragalactic objects, it is targeting millions of Milky Way stars, including white dwarfs. Using Data Release 1 we assemble the largest catalogue of spectroscopically-confirmed white dwarfs to date, whose straightforward selection function enables statistically-robust population studies. We visually inspect and fit models to sp…

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astro-ph.HE

A Swift X-ray view of the SMS4 sample - III: Deeper insight into previously undetected sources

Alessandro Maselli, William R. Forman, Christine Jones, Ralph P. Kraft, Matteo Perri

We update the X-ray information given in Maselli et al. (2024) for five bright radio sources in the SMS4 catalog, thanks to additional observations with the X-Ray Telescope (XRT) on board the Neil Gehrels Swift Observatory (hereafter Swift) carried out through February 2026. X-ray emission from MRC B1754-597, previously based only on data from the eROSITA-DE DR1 catalogs, is now detected also by Swift, which yields a more precise positional uncertainty. Thanks to ~7 ks of additional exposure wit…

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astro-ph.HEastro-ph.GAastro-ph.SR

Nebular Spectra of the Extremely Metal-Poor SN II 2023ufx Over a Year After Explosion: A Massive Progenitor and Unique Circumstellar Environment

Evan Jennerjahn, Michael A. Tucker, Christopher S. Kochanek, Luc Dessart, Willem B. Hoogendam, Benjamin J. Shappee

We present new observations of the metal-poor ($< 0.1$ $\rm Z_\odot$) Type II supernova 2023ufx and its host galaxy. The deep nebular spectrum, obtained roughly a year after explosion, has a triple-peaked [O I] emission profile suggesting an asymmetric explosion. Comparison to nebular spectra models suggests a zero-age main sequence mass of $ M_{\rm ZAMS} \sim 25-35$ $\rm M_\odot$, which is supported by the low [Ca II]/[O I] emission-line ratio of $\approx0.4$. The diminishing, broad, boxy H$α$…

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astro-ph.COastro-ph.HEhep-ph

Supernova microlensing as a probe of ultracompact minihalos and primordial cosmology

Djuna Croon, Sergio Sevillano Muñoz, Miguel Zumalacarregui

We propose using supernova microlensing to search for ultracompact minihalos and other extended dark structures seeded by enhanced primordial small-scale power. Unlike conventional microlensing searches, which are often optimized for primordial black holes, cosmological supernovae are sensitive to lenses with physical sizes comparable to their Einstein radii (up to $\sim {\rm pc}\left(M/10^4M_\odot\right)^{1/2}$ scale), opening a qualitatively different region of dark object parameter space. We…

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astro-ph.IMquant-ph

Development of quantum technologies for optical/infrared interferometry

John D. Monnier

Quantum technologies may revolutionize optical interferometry through new means to distribute and preserve electric-field amplitude and phase correlations between widely separated telescopes. After reviewing existing techniques, I survey proposed quantum-sensing and quantum-networking applications and highlight recent laboratory demonstrations of key building blocks. By easing field-transport demands for baselines beyond $\sim$1 km, quantum-enhanced interferometry could enable sub-milliarcsecond…

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astro-ph.IMastro-ph.EPcs.LG

TNFlow: Amortized Posterior Inference for Trans-Neptunian Object Surface Composition

Agastya Gaur, Cristina M. Dalle Ore, Alessandra Ricca

We present TNFlow, a transformer and normalizing flow architecture for inferring the surface composition of Trans-Neptunian Objects (TNOs) from their reflectance spectra. TNFlow is trained on synthetic spectra generated by the Shkuratov radiative transfer model to act as its inverse. TNFlow takes ${\sim}$0.7s to invert one spectrum on a single CPU core, returning a multimodal posterior over simplex-valid compositions and grain sizes. On synthetic spectra, the highest-weight mode achieves a mean…

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astro-ph.HE

Low-angular-momentum accretion shocks can power weak-to-moderate X-ray flares from SgrA*

Samik Mitra, Bożena Czerny, Michal Zajaček, Zach Sumners

X-ray flares from Sgr~A* span broad ranges in duration, fluence, and luminosity, but their origin remains unsettled. We test whether standing shocks in low-angular-momentum magnetized accretion flows can provide a viable energy reservoir to account for these events. Using semi-analytic trans-magnetosonic shock solutions, we estimate the kinetic energy available in the downstream post-shock flow and compare it with the 25-year \textit{Chandra} X-ray flare catalog. For each theoretical solution, w…

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astro-ph.GAastro-ph.HE

Fundamental differences in the X-ray accretion properties of low and high-excitation radio galaxies

R. Kondapally, T. Holc, P. N. Best, J. Aird, K. J. Duncan, L. K. Morabito, D. M. Alexander, D. J. B. Smith et al.

We characterise the accretion rate properties of radio-detected AGN by combining deep radio and X-ray observations of the Boötes field. We used deep international LOFAR telescope observations to identify 2840 radio-AGN across $0.3 < z \leq 2$, divided into samples that are complete in radio luminosity. We further split this sample into four different classes: radio-quiet AGN (RQ-AGN), high-excitation radio galaxies (HERGs), and low-excitation radio galaxies (LERGs) hosted by star-forming (SF-LER…

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astro-ph.HEastro-ph.GA

A targeted search for fast radio bursts from magnetars in elliptical galaxies

S. Paine, D. R. Lorimer, S. Sirota, G. M. Doskoch, S. Tabassum, M. Flanagan, J. Lituchy, A. Stone et al.

Motivated by predictions that globular clusters associated with nearby giant elliptical galaxies are prime environments for detecting fast radio bursts (FRBs) from magnetars, we report on a targeted high-sensitivity search across five local massive elliptical galaxies. We utilized the GREENBURST single-pulse search pipeline and the VEGAS backend on the Green Bank Telescope (GBT) to conduct an L-band (1.4 GHz) survey for FRBs in each target environment. We discovered FRB 20240817A in the directio…

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astro-ph.GAastro-ph.IM

Absolute Motion of the Infrared Counterpart to Sagittarius A* in the Gaia Celestial Reference Frame 3 and Limits on an Intermediate-mass Black Hole Companion

Rebecca A. Lewis-Merrill, Tuan Do, Matthew W. Hosek, Gregory David Martinez, Shoko Sakai, Kelly Kosmo O'Neil, Grant Weldon, Abhimat Gautam et al.

We report the first proper motion and acceleration measurements of the infrared (IR) counterpart to Sagittarius A* (Sgr A*-IR), the supermassive black hole (SMBH) at the center of our Galaxy, in the Gaia-Celestial Reference Frame (Gaia-CRF3). This reference frame realizes the International Celestial Reference System (ICRS), which is an absolute reference coordinate system defined by quasars. A combination of Gaia and Hubble Space Telescope data was used to transform Keck adaptive optics (AO) obs…

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astro-ph.HEastro-ph.GAgr-qc

Sgr A* as a Galactic PeVatron: Multimessenger Signatures of the Magnetic Penrose Process

Marina Cermeño, Pedro De la Torre Luque, Cristina Fernández-Suárez, Viviana Gammaldi, Enrique Mier-Alonso, María J. Rodríguez, Miguel Á. Sánchez-Conde, Jaume Zuriaga-Puig et al.

The magnetic Penrose process (MPP) is one of the most efficient mechanisms for extracting rotational energy from a magnetized Kerr black hole (BH), enabling charged particles to reach very-high energies. We investigate this process in Sagittarius A* (Sgr A*), the supermassive BH at the Galactic center (GC), focusing on its ultra-high-efficiency regime, in which neutrons undergo beta decay inside the BH ergosphere. As a key novelty, we compute the neutron production spectrum in the accretion flow…

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astro-ph.SRastro-ph.GA

Ionized Nebulae Around Two New Symbiotic Stars: GR Cygni and [D75] 141

Howard E. Bond, Calvin Carter, Sven E. Eklund, Peter Goodhew, Ulisse Munari, Jonathan Talbot, Gregory R. Zeimann

In the course of selecting targets for a spectroscopic survey of faint planetary-nebula nuclei, we encountered two anomalous cases of late-type variable stars surrounded by nebulosities discovered by amateur astronomers. We obtained follow-up deep narrow-band images of the two nebulae: StDr Objet 14 (diameter 1.5 arcmin) and StDr 4 (diameter 2.5 arcmin). StDr Objet 14 is found to be a low-excitation nebula, bright only in Ha+[N II], and showing a unique double-ring "bull's-eye" morphology. StDr…

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astro-ph.GA

Two sets of potential-density basis pairs for the study of radial perturbations in collisionless spherical stellar systems

E. V. Polyachenko, I. G. Shukhman

The Kalnajs matrix method is a widely used framework for studying the global linear stability and possible Landau damping of collisionless stellar systems. However, for radial perturbations ($l=0$) in three-dimensional spherical models with infinite boundaries, standard biorthogonal sets such as the Clutton-Brock basis often converge slowly. This stems from a physical constraint: mass-conserving radial modes force the perturbed potential to decay faster than a point mass at infinity, whereas ind…

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gr-qcastro-ph.HE

Eight Local Couplings of Gravitational Waves from Unified Field Equations

Hong-Bo Jin, Yue-Liang Wu

A gravitational-wave (GW) detector records a linear mixture of local couplings under the assumption that extra polarizations enter geodesic deviation. Vacuum general relativity (GR) admits two transverse-traceless (TT) amplitudes. It remains to determine the largest set of couplings that can sit in that mixture, and whether a tensor-only arm-length result selects GR uniquely. The little group \(E(2)\) of a null four-momentum classifies the strain amplitudes \(\mathbf{p}=(p_{+},p_{\times},p_{x},p…

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astro-ph.EPastro-ph.IMastro-ph.SRphysics.ao-phphysics.space-ph

Detection of hydrocarbons in Titan using high-resolution cross-correlation spectroscopy

Maria Coelho, Rafael Rianço-Silva, Diogo Gonçalves, Pedro Machado, Zita Martins

High-resolution cross-correlation spectroscopy (HRCCS) is a powerful technique for detecting molecules whose individual spectral lines are too weak to be identified directly, but its sensitivity is limited by the availability and quality of high-resolution opacity data. Many molecules of atmospheric and astrobiological interest lack complete line lists, restricting traditional template-based searches. In this work, we use Titan as a controlled testbed to develop and validate a new cross-section-…

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astro-ph.HEhep-phnucl-th

Ultra-compact twin stars with hybrid equations of state from bosonic dark matter

Ishfaq Ahmad Rather, Sarah Louisa Pitz, Jürgen Schaffner-Bielich

The properties of compact stars with a strong first-order phase transition to quark matter and with an additional fluid of self-interacting bosonic dark matter (DM) are studied. We find that the inclusion of DM changes considerably the stability of mass-radius configurations relative to the naive one-fluid criterion. For compact star configurations with similar masses and different radii, so-called twin stars, the presence of DM removes the unstable segment between the hadronic and the hybrid br…

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astro-ph.SR

Interferometric Survey of Stellar Parameters: Mass of the metallic A-type binary $β$ Aur

J. Jonák, D. Mourard, J. D. Monnier, S. Hoin, M. Brož, A. Oplištilová, K. A. Kubiak, N. Ebrahimkutty et al.

With the capabilities of the new visible CHARA/SPICA instrument and the multiple spectral band operation of CHARA, our goal is to resolve orbits of short-period binaries and develop a robust framework for combining interferometric, spectroscopic, and photometric observations into a single consistent model. For our target sample, we selected suitable binaries based on brightness, angular separation, and orbital properties based on the expected performance of the CHARA/SPICA instrument. As a case…

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