研究動向

astro-ph.EP2026年9月15日

Thermophysical characterization of the potentially hazardous near-Earth object 2024 YR4

T. G. Müller, E. M. MacLennan, A. Y. Burdanov, B. J. Holler, A. S. Rivkin, J. de Wit, P. Pravec, M. Micheli et al.

The asteroid 2024 YR4 is a potentially hazardous Apollo-type near-Earth object. Its highly eccentric orbit produces close Earth-Moon encounters roughly every 4 years. A collection of light curves, including JWST-NIRCam data, allowed us to constrain the rotation period, spin pole, and convex shape solutions for the object. We analyzed two sets of JWST-MIRI observations obtained in three filters on 26 March 2025. The extracted photometry reveals rotationally driven thermal flux variations. The com…

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astro-ph.COastro-ph.GAhep-ph2026年9月15日

Using the Circumgalactic Medium of Dwarf Galaxies as a Calorimetric Dark Matter Detector

Abby Mintz, Digvijay Wadekar, Romain Teyssier

Many well-motivated dark matter (DM) scenarios, including dark photon DM, axion-like particles, sterile neutrinos, and primordial black holes, can deposit energy into ordinary matter and significantly raise the thermal energy of astrophysical gas. We present a simple, model-independent implementation of DM-induced heating in the RAMSES hydrodynamic simulation code, parameterized by an effective local heat-transfer rate $Γ_{\rm heat}$. Using simulations of an isolated gas-rich dwarf galaxy with p…

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astro-ph.IM2026年9月15日

Automatic astrometric calibration of low-cost all-sky cameras

J. R. González Fernández, Laura Hermosa Muñoz, María Fernández Alonso, Lucía González Cuesta

All-sky cameras support weather monitoring, amateur astronomy, fireball and space-debris detection, and measurements of light pollution. These applications require reliable astrometric calibration despite imperfect camera alignment and variable observing conditions. We present an open-source procedure that combines a compact fisheye model, an exact rotation to account for camera tilt, and automatic star matching. It can initialise a calibration from a single frame given the observing site coordi…

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astro-ph.HE2026年9月15日

Iron Nuclei with Energy of 10^19 eV in Extragalactic Cosmic Rays Near Earth

Anna Uryson

The paper discusses the fraction of extragalactic cosmic iron nuclei with energies of 10^19 eV that reached Earth from distant sources without fragmentation in intergalactic space. It is shown that the fraction of particles with energies E = 10^19 eV is significant (about 10%), even if the redshifts of the sources reach 0.2, and not only for nearby sources.

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physics.opticsastro-ph.IM2026年9月14日

Setup and performance of focal-plane characterization benches for high precision astrometry

Fabrice Pancher, Sebastien Soler, Fabien Malbet, Hugo Rousset, Manon Lizzana, Alain Leger, Thierry L{é}pine, Florence Ardellier-Desages et al.

Detecting Earth-like exoplanets requires micro-arcsecond astrometry, which relies on a precisely calibrated focal plane equipped with high-resolution detectors. Accurate calibration depends on characterizing detector imperfections and systematic effects. Optical benches have been developed to assess the sensor's behavior: an integrating-sphere setup for electro-optical parameters, an interferometric bench for pixel-level geometry, and a star-field projection system for intrinsic distortion. This…

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astro-ph.HE2026年9月14日

Compelling evidence of a link between the lags of the quasi-periodic oscillations and the radio jet in the black-hole X-ray binary GRS 1915+105

Candela Bellavita, Mariano Méndez, Federico García, Sara Motta, Pengcheng Yang, Wyncko Tonckens, Liang Zhang, Rob Fender et al.

GRS 1915+105 is one of the most studied black-hole X-ray binaries, known for its extreme variability and rich phenomenology. Previous studies of this source with the Rossi X-ray Timing Explorer reported a transition of the phase-lags of type-C quasi-periodic oscillations (QPOs) from soft, where low-energy photons lag the high-energy ones, when the QPO frequency is higher than ${\sim} 2 ~{\rm Hz}$, to hard when the QPO frequency decreases below ${\sim} 2 ~{\rm Hz}$. The hard-lags of the QPO coinc…

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astro-ph.SR2026年9月14日

Stellar activity in a post-merger Giant star

Hans Moritz GGunther, C. Melis, K. J. Shen, Eric G. Blackman, K. Hoadley, P. C. Schneider

Binary stars are the progenitors of exotic objects, such as supernovae and gravitational wave sources. However, some systems merge earlier when the primary expands into a giant star at the end of its lifetime on the main sequence and causes its companion to spiral in. TYC 4144-329-2 is a candidate post-merger first ascent giant star with a circumstellar disk seen in the infrared (IR). We detect weak X-ray and far ultraviolet (FUV) emission from TYC 4144-329-2, which we interpret as a signature o…

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astro-ph.GAastro-ph.SR2026年9月14日

Constraining the Delay Time Distribution of the r- and s-Process from Stellar Ages at Solar Metallicity

Meng Zhang, Hans-Walter Rix

We present a new approach to constraining the delay time distribution (DTD) governing r- and s-process element production. Rather than using metallicity as a proxy for time, we work directly with stellar ages at solar metallicity, where chemical equilibrium models are most applicable. We analyze two complementary samples: more than $10,000$ red clump (RC) thin disk stars at solar metallicity from LAMOST, and solar twins with high-precision abundances; both have well-determined stellar ages $τ$.…

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astro-ph.IM2026年9月14日

Calibrations for high precision differential astrometry onboard Theia and HWO

Manon Lizzana, Fabien Malbet, Hugo Rousset, S{é}bastien Soler, Fabrice Pancher, {É}ric Thi{é}baut

Future space astrometry missions such as Theia and an astrometric mode of the Habitable Worlds Observatory (HWO) require detector calibration and instrumental characterization at an unprecedented level to achieve sub-micro-arcsecond precision. This work presents three complementary developments addressing these requirements. First, we report an independent characterization of the GIGAPYX-4600 back-side illuminated CMOS detector, evaluating its linearity, readout noise, dark current, pixel respon…

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astro-ph.GA2026年9月14日

The Multiphase CGM in the Epoch of Reionization: CII and CIV absorbers around [OIII] Emitters

C. Piscitelli, V. D'Odorico, M. Galbiati, M. Bischetti, G. Cupani, R. Dutta, S. Cantalupo, S. Di Stefano et al.

We investigate the multiphase circumgalactic medium (CGM) during the Epoch of Reionization (EoR, $z>6$) by cross-correlating cool- CII and warm-ionized CIV absorption systems with star-forming [OIII] emitters. JWST/NIRCam wide-field slitless spectroscopy from the EIGER survey is combined with medium- and high-resolution optical/NIR spectra of six background quasars, including new VLT/X-Shooter observations of PSO J159-02. We analyze the relation between 16 CII and 14 CIV absorbers ($\log(N) > 13…

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astro-ph.COastro-ph.GA2026年9月14日

Anisotropic redshift distributions in photometric galaxy clustering and their cosmological impact

Zekang Zhang, Yunhe Wang, Daniel Gruen, Hui Kong, Luca Tortorelli, Silvan Fischbacher, Ziang Yan

Photometric galaxy clustering is a major probe of large-scale structure whose interpretation relies on accurate characterization of the galaxy redshift distribution, $n(z)$. Standard analyses assume the $n(z)$ of a selected lens sample to be isotropic, whereas observational systematics can imprint spatial variations. We quantify how this anisotropy biases angular galaxy clustering, internal consistency, and cosmological inference. We develop an analytical formalism for clustering under spatially…

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astro-ph.GA2026年9月14日

ALMA-JELLY II. Constraining the radial profiles of the quenching timescales in ram-pressure-stripped galaxies

Roberto P. Infurna, Matteo Fossati, Alessandro Boselli, Michele Fumagalli, Jeffrey D. P. Kenney, Pavel Jáchym, Ming Sun, Elias Brinks et al.

We investigate the environmental quenching histories and spatial progression of ram-pressure stripping in 11 galaxies in the nearby Coma, Norma, and A1367 clusters. As part of the ALMA-JELLY large program, we combine high-sensitivity VLT/MUSE integral-field spectroscopy with ultraviolet-to-far-infrared photometry in 37 spatially resolved disc apertures. The sample spans $\log(M_*/\mathrm{M}\odot)\sim7.5-10.5$ and includes galaxies undergoing active or recent ram-pressure stripping, identified th…

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astro-ph.IM2026年9月14日

Gnuastro: removing extended/diffuse outliers while coadding

Mohammad Akhlaghi, Héctor Vives Arias, Pablo Renard, Héctor Vázquez Ramió, Raúl Infante-Sainz

Deep astronomical images are produced by the coadding (also called "stacking") of several individual exposures. However, individual exposures are often plagued with many artifacts which will reduce the quality of the deep image if not properly removed. Most are removed during reduction/calibration, but the more diffuse may stay. To address this problem, the following new operators were introduced to the Arithmetic program in Gnuastro 0.23: 'madclip-maskfilled', 'sigclip-maskfilled' and 'collapse…

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astro-ph.EPastro-ph.IM2026年9月14日

Detecting transiting exoplanets in simulated PLATO data: A comparison of light curve filter and transit search algorithms

Geert Jan Talens, Leigh C. Smith, Luca Malavolta, Lionel Garcia, Simon Hodgkin, Suzanne Aigrain

Aims: Our goal is to test and compare transit search methodologies, and provide recommendations as to the best practices to be implemented by the upcoming ESA PLATO mission, in order to achieve its goal of detecting Earth-like planets in the habitable zones of Sun-like stars. Methods: We generate simulated two-year PLATO light curves with injected planets with sizes 0.5--2.0 $R_\oplus$, and compare the performance of the CETRA, umbra, and nuance transit search methods. CETRA and umbra require pr…

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gr-qcastro-ph.HE2026年9月14日

Magnetic Reconnection Heating of Thin Accretion Disks around Kerr Black Holes

Zhen Li

The magnetic reconnection process near a black hole can efficiently convert magnetic energy into the kinetic and thermal energy of plasma outflows, enabling the extraction of rotational energy from a spinning black hole. However, its impact on the surrounding accretion disk remains insufficiently explored. In this work, we develop a framework to investigate the 'heating' effect of magnetic reconnection outflow plasma on thin accretion disks around Kerr black holes. We incorporate the energy and…

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astro-ph.HEastro-ph.GAgr-qc2026年9月14日

The effect of pressure confinement on the maximum mass of rapidly accreting supermassive stars

Lorenz Zwick, Christopher Tiede, Zoltán Haiman

We derive an extension of Chandrasekhar's pulsational stability criterion for relativistic stars with a pressure boundary condition at the surface. We then apply the new criterion to hylotropes, a model describing rapidly accreting supermassive stars with a core-envelope structure. We find that confinement typically stabilises stars, delaying the onset of the general relativistic instability when the external pressure at the surface is roughly $\sim10^{-3}$ of the stars' hydrostatic pressure sca…

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astro-ph.SR2026年9月14日

MINCE IV. A detailed analysis of 37 metal-poor and subsolar metallicity stars

L. Sgatti, G. Cescutti, L. Lombardo, C. T. Nguyen, P. Bonifacio, E. Caffau, L. Monaco, R. Lallement et al.

The project called Measuring at Intermediate metallicity Neutron-Capture Elements (MINCE) primarily focuses on the photospheric abundances of several neutron-capture (NC) elements from high-quality spectra of metal-poor stars within the metallicity range of ${\rm -2.5 \leq\![Fe/H]\!\leq -1.5}$, aiming to provide homogeneous information on their chemical compositions. Furthermore, based on the Gaia mission, chemical abundances can now be coupled with kinematic properties, enabling investigations…

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astro-ph.COastro-ph.GA2026年9月14日

Assembly Bias in eRASS1 X-ray Galaxy Clusters: Accounting for Non-uniform Survey Exposure

Jitendra Joshi, Divya Rana, Surhud More

Halo assembly bias describes the dependence of halo clustering on properties beyond halo mass and provides a means of connecting halo assembly history to the large-scale matter distribution. We develop and test a relative clustering methodology for measuring differences in the large-scale bias of two halo populations using the ratio of their cluster--galaxy pair counts. In the linear regime, this ratio can be related to the difference in cluster bias, while the galaxy autocorrelation independent…

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astro-ph.IMastro-ph.SRmath-ph2026年9月14日

PYRA and MYTHRA: new statistical analysis for image reconstruction

Julien Drevon, Margaux Abello, Florentin Millour, Anthony Meilland, Armando Domiciano de Souza

Image reconstruction in optical interferometry remains a challenging inverse problem due to sparse Fourier sampling and the strong dependence of the reconstructed images on user-defined parameters. We present PYRA (Python for MiRA) and MYTHRA (Mean Astrophysical Images with PYRA), two tools designed to improve the robustness and reproducibility of interferometric imaging. PYRA automatically generates large ensembles of MiRA reconstructions by exploring a wide range of reconstruction parameters,…

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astro-ph.SRastro-ph.EP2026年9月14日

SPAMMS: 3D spectroscopic modelling of stellar surfaces. II. Implementation of Kurucz and TLUSTY model atmospheres

D. Galán-Diéguez, M. Abdul-Masih, C. Allende Prieto, S. R. Berlanas, A. Herrero, H. Sana

Context. Accurate stellar spectra are essential to derive stellar properties. Traditional model atmospheres often oversimplify phenomena that break spherical symmetry, such as rotational deformation or multiplicity. The Spectroscopic PAtch Model for Massive Stars (SPAMMS) accounts for these effects, but its applicability has been limited by the spectral types covered by its model atmosphere grids. Aims. We aim to extend the parameter space of the model atmosphere grids available to SPAMMS, enabl…

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gr-qcastro-ph.HEastro-ph.IMastro-ph.SR2026年9月14日

Deterministic denoising of long-duration gravitational-wave signal candidates with $α$-(de)blending

Przemysław Figura, Michał Bejger

We present a deterministic machine-learning method for denoising candidate signals from all-sky searches for continuous gravitational waves from rotating neutron stars. Using the time-domain $F$-statistic search pipeline, we post-process the resulting $F(f,\dot{f})$ candidate patterns with iterative $α$-(de)blending, a deterministic diffusion-type generative model implemented as a U-Net, well suited to the non-Gaussian, correlated noise of the $F$-statistic output. Two models, trained on data ba…

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gr-qcastro-ph.EPastro-ph.IM2026年9月14日

Testing the equivalence principle with lunar laser ranging residuals from different planetary and lunar ephemerides

Jun Ke, Jie Luo, Qin Li, Yu-Jie Tan, Cheng-Gang Shao

Lunar laser ranging (LLR) provides a sensitive test of the equivalence principle (EP) through a possible synodic perturbation in the Earth--Moon distance. In this work, we develop an independent LLR data-reduction framework and investigate this signature in the post-fit O--C residuals obtained with the EPM21, INPOP21, and DE430 planetary and lunar ephemerides. The same observation model and parameter-adjustment procedure are applied to the three ephemerides, allowing their residual-based results…

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astro-ph.HE2026年9月14日

Spectro-polarimetric study of the black hole X-ray binary Swift J1727.8-1613 in the JED-SAD framework

R. Muhammad, P. -O. Petrucci, W. Zhang, J. Ferreira, R. Belmont, J. Malzac, G. Marcel, G. Matt et al.

Context. Swift J1727.8-1613 is an X-ray binary observed during its 2023-2024 outburst, including bright and dim hard states with similar X-ray polarimetric signatures but fluxes differing by two orders of magnitude. Aims. We aim to reproduce the spectro-polarimetric properties of these two hard states. Methods. We modelled their spectra in the JED-SAD framework and computed the X-ray polarisation properties of the best-fit configurations with the MONK general relativistic radiative transfer code…

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astro-ph.GA2026年9月14日

Highly Ionized Oxygen in the Circumgalactic Medium of TNG100 Galaxies: Distributions, Thermal States, and Ionization Mechanisms

Yossi Oren, Amiel Sternberg, Christopher F. McKee, Yakov Faerman

We investigate the origin of the highly ionized oxygen species, O VI, O VII, and O VIII, in the circumgalactic medium (CGM) of galaxies at redshifts $z \approx 0$, by post-processing the outputs of the Illustris TNG100 simulation alongside analytic modeling. Our computations are broadly consistent with observations, and we provide convenient functional fits for the predicted mean oxygen ion column densities as functions of halo virial mass. We determine the relative roles of electron impact coll…

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astro-ph.SR2026年9月14日

A Self-consistent Model for the Generation of Coronal Condensations: The Effects of Turbulent Wave Dissipation

M. McMurdo, V. Jercic, T. Van Doorsselaere, C. Froment

Prominences and coronal rain are two manifestations of coronal condensations whose formation mechanisms remain only partially understood. While previous studies have explored how localised steady or stochastic heating can trigger thermal instability and condensations, the role of wave driven energy transport and dissipation has not been extensively investigated. In the solar atmosphere, Alfven and kink waves are an abundant source of energy capable of contributing both to coronal heating and pla…

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astro-ph.GA2026年9月14日

The WISSH quasars project XIII. A multi-epoch study of ultra-fast broad absorption line outflows at cosmic noon

A. Deconto-Machado, G. Vietri, E. Piconcelli, S. Bisogni, T. Misawa, A. Gargiulo, G. Lanzuisi, A. Travascio et al.

Ultra-fast broad absorption line outflows (uBAL, ~0.1-0.2c) represent some of the most extreme manifestations of quasar-driven winds. We aim to investigate the variability of uBALs through their characterisation across different epochs and multiple ionic species. The main goal is to constrain their physical properties, locations, and kinetic powers to evaluate their potential impact on the respective quasar host galaxies. We performed a multi-epoch analysis of three hyper-luminous quasars from t…

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astro-ph.SRastro-ph.GA2026年9月14日

A new method to cleanly separate hot and cool populations using just Gaia and 2MASS photometry

J. Maíz Apellániz, M. Pantaleoni González

We have developed a photometric method that produces clean hot (intrinsically blue) populations using Gaia and 2MASS photometry alone with [a] a very small (false positives < 1%) contamination from cool (intrinsically red) luminous sources, [b] independent of extinction (limited only by S/N), and [c] with only small losses (false negatives < 10%) of real OB stars. Applying the method to Gaia DR3 data we are able to recover extinguished OB stars down to E(G_BP-G_RP) = 5, producing a catalog of ~2…

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astro-ph.HE2026年9月14日

Discovery of Two Consecutive Profile Change Events in the Millisecond Pulsar PSR J0437-4715

Rami F. Mandow, Andrew Zic, J. R. Dawson, Shuangqiang Wang, Małgorzata Curyło, Bhavnesh Bhat, Michael J. Keith, N. D. Ramesh Bhat et al.

The closest and brightest millisecond pulsar (MSP), PSR J0437-4715, is a high-priority pulsar for precision timing experiments, including the Parkes Pulsar Timing Array (PPTA) project, where it is used for both pulsar timing and for polarization calibration. Using approximately seven years of observations obtained with the Ultra-Wideband Low-Frequency receiver on Murriyang, CSIRO's Parkes radio telescope, we investigate the long-term spectro-polarimetric variability of PSR J0437-4715. We report…

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astro-ph.HEastro-ph.CO2026年9月14日

Physics-Informed Neural Networks and Data-Driven Models for GRB X-ray Light-Curve Gap Reconstruction

Ayush Garg, Ritik Kumar, Maria G. Dainotti, Vipul Sharma, Amit Shukla, Dieter H. Hartmann

Swift-XRT X-ray afterglows of gamma-ray bursts (GRBs) frequently contain temporal gaps that limit the precision with which the Willingale et al. 2007 (W07) plateau parameters measure plateau end time $T_a$, plateau flux $F_a$, and post-plateau decay index $α$. Because these parameters underpin the Dainotti relations (Dainotti et al. 2008, Dainotti et al. 2010, Dainotti et al. 2017), reducing their measurement uncertainty directly improves the cosmological statistical power of GRBs. As the fifth…

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astro-ph.SRastro-ph.GA2026年9月14日

Results on young stellar clusters with the WEAVE LIFU

J. Maíz Apellániz, G. Holgado, C. Fariña, S. R. Berlanas

We present the first results of two Spanish TAC programs using the WEAVE LIFU that have been obtaining data since October 2023. The first one is obtaining high-resolution multi-epoch spectroscopy of the nine stellar clusters that contain a minimum number of 3 O-type stars (and many more B stars) within the field of view of the WEAVE LIFU and that are accessible from La Palma with the purpose of studying the spectroscopic multiplicity of the OB stars. The second program is obtaining single-shot l…

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