研究動向

astro-ph.EP2026年9月29日

Homogeneous Nucleation of Water Vapor Evidenced by Elongated Clouds on Mars

J. Hernandez-Bernal, A. Maattanen, A. Spiga, F. Forget

It is widely accepted that water vapor forms clouds by heterogeneous nucleation (condensation on pre-existing dry nuclei). Homogeneous nucleation (directly from water vapor, without a pre-existing nuclei) is theoretically possible, but it requires high levels of supersaturation and so it is not considered a viable cloud formation process under real atmospheric conditions. Here, we show that introducing homogeneous nucleation in a meteorological model of Mars allows to successfully reproduce the…

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gr-qcastro-ph.IM2026年9月29日

Gravitational-Wave Inference For Noise PSD Jumps Across Data Gaps

Jian-Ming Yan, Zong-Kuan Guo

Long-duration gravitational-wave (GW) inference inevitably encounters data gaps, which are often accompanied by abrupt, non-stationary changes in the detector noise power spectral density (PSD). Conventional practice typically analyzes the pre-gap and post-gap data separately, causing avoidable information loss and potentially degrading parameter inference. We build on Bayesian gap augmentation in the Wilson--Daubechies--Meyer (WDM) time--frequency domain and focus on a practically important fai…

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gr-qcastro-ph.COastro-ph.GAastro-ph.HE2026年9月29日

The Irreversible Depletion of Dark Matter Spikes by Extreme-Mass-Ratio Inspirals

Charlie Sharpe, Yonadav Barry Ginat, Thomas F. M. Spieksma, Alexander Heger, Bence Kocsis

Dense dark matter spikes around massive black holes (MBHs) have been widely predicted to produce gravitational-wave dephasing in extreme-mass-ratio inspirals (EMRIs) that are potentially observable by LISA. We show that EMRIs, the very objects used to probe these spikes, also destroy them. Combining Fokker-Planck models of nuclear star clusters with post-Newtonian three-body simulations of EMRI-dark matter encounters, we demonstrate that repeated gravitational slingshots irreversibly eject dark…

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astro-ph.HE2026年9月29日

Multi-wavelength polarization degree dependence of Mrk 421 for different particle energy distributions

Hritwik Bora, Ranjeev Misra, Rupjyoti Gogoi

We report on the constraints obtained from the multi-wavelength polarization degree and energy spectra measurements for the High Synchrotron Peaked Blazar (HBL) source Mrk 421 using different forms of the electron energy distribution. We find that the optical and X-ray data are consistent with the electron energy distribution being a broken power-law (BPL) or other distributions, with all electrons experiencing the same magnetic field configuration. This is in contrast to other HBL sources like…

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astro-ph.GA2026年9月29日

MEGATRON: Dwarf Galaxy Quenching in the Epoch of Reionization

David Attard, Ilian T. Iliev, Martin P. Rey, Harley Katz, Corentin Cadiou, Nicholas Choustikov

Low-mass galaxies during the Epoch of Reionization are expected to form stars in short bursts separated by periods of inactivity, but what regulates this cycle, and how sensitive it is to the modelling of stellar feedback, remains unclear. We use the MEGATRON high-redshift zoom simulation suite, in which four star-formation and stellar-feedback prescriptions are evolved from identical initial conditions, to study the regulation of stellar mass growth in galaxies with $M_{*} \sim 10^{4} - 10^{8}…

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astro-ph.SR2026年9月29日

On the frequency-dependent time lags of the intermediate polar V709 Cas

Zackery A. Irving, Noel Castro Segura, Diego Altamirano, Martina Veresvarska, Mariano Mendez, Federico Garcia, Domitilla de Martino, Simone Scaringi et al.

Cataclysmic variables (CVs) are binary systems in which a white dwarf (WD) primary accretes material from a late-type secondary, typically via a disc. To date, only six CVs, all of which are non-magnetic, have been found to exhibit lags (delayed variability in one band with respect to another). In all six cases, these lags are ``red'' (i.e., red lags blue) with a time lag of order seconds. While there is no generally accepted mechanism for producing red lags in CVs, current theories suggest repr…

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astro-ph.EP2026年9月29日

Chondrule size averaging in two and three dimensions

Emmanuel Jacquet

Chondrule sizes are an important discriminant of chondrite groups and chondrule formation theories. Yet most studies report 2D sizes without attempting the somewhat tedious corrections to 3D proposed in the past literature. I show here that 3D size averages can be simply calculated directly from 2D averages of appropriate powers of sizes (and vice-versa), without having to reconstruct 3D distributions, although explicit formulas to that end are also provided. This illuminates the comparison betw…

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astro-ph.EP2026年9月29日

Astrometric Evidence for Outer Giant Planets in Known Exoplanet Systems

Clarissa R. Do Ó, William Thompson, Dori Blakely, Aniket Sanghi, Jerry W. Xuan, Dimitri Mawet, Jessica Speedie, Sarah Blunt et al.

Outer giant planets can influence the formation and dynamical evolution of their planetary systems. However, their long orbital periods make them difficult to detect using transit and radial velocity (RV) techniques. Measurements from Hipparcos, Gaia DR2 and DR3 (G23H) can detect the stellar reflex motion induced by distant companions before the release of Gaia DR4 epoch astrometry. Using the G23H catalogue, we identify 29 outer companion candidates ($a_{median}$ $>$ 8.4 AU) in known transiting…

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astro-ph.IM2026年9月29日

First laboratory demonstration of iEFC for high-contrast imaging at small angular separation on ELT scales

Charles Sallard, Patrice Martinez, Alain Spang, Kian Milani, Lyu Abe, Mathilde Beaulieu, Carole Gouvret, Aurélie Marcotto et al.

Implicit electric field conjugation (iEFC) is an efficient, model-free wavefront control technique for dark hole creation. Its model-free nature, relying on calibration with real data rather than a synthetic model of the instrument, makes it uniquely versatile and highly attractive. It has been successfully demonstrated in a variety of environments, both in the laboratory and on-sky, using different experimental platforms and coronagraphs. A common characteristic of these demonstrations is that…

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astro-ph.HE2026年9月29日

Re-interpreting the GRS 1915+105 observations within the variable TADAF scenario

Chun Xu

The Galactic microquasar GRS 1915+105 is one of the most interesting X-ray binary systems, exhibiting an exceptionally diverse range of observational phenomena. It displays the most complicated and variable X-ray light curves and carries superluminal radio jets. Its X-ray and radio fluxes change on very different timescales, from seconds to minutes to days and even longer. In recent years, its jet has also displayed large position angle shifts. We find that most of the observational phenomena ca…

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astro-ph.EPastro-ph.GAastro-ph.HEastro-ph.IM2026年9月29日

Detecting Extragalactic Exoplanets With Fast Radio Burst Nanolensing

Kenneth F. Olibrice, Dylan L. Jow

Fast Radio Bursts (FRBs) are spatially and temporally compact sources at cosmological distances. As background sources, they will be uniquely sensitive to the gravitational lensing of exoplanets outside of our own galaxy. We present a method to detect extragalactic exoplanets using planetary echo nanolensing-periodic, nanosecond-scale variations in the relative time of arrival (ToA) between an initial FRB and its microlensed echo as the planet orbits its host star. For a simple binary lens model…

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astro-ph.SRastro-ph.HE2026年9月29日

LISA Double White Dwarfs in Triple Systems

Zhijun Wang, Guoliang Lü, Chunhua Zhu, Xizhen Lu, Sufen Guo, Helei Liu, Renyu Luo, Tian Huang et al.

Double white dwarfs (DWDs) in the Laser Interferometer Space Antenna (LISA) band are major Galactic gravitational-wave sources, but many tight DWD progenitors may reside in hierarchical triples. Triple evolution can alter both the production rate and parameter distributions of LISA DWDs. Using the Multiple Star Evolution (MSE) code, we study how the adiabatic mass-loss model (Ge model) and the SCATTER formalism for triple common-envelope (TCE) evolution affect triple-channel LISA DWD formation.…

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astro-ph.IMastro-ph.GA2026年9月29日

LUMA: A CNN for Strong Gravitational Lens Searches in Astronomical Imaging

Giovanni Vincenzo Donatiello, Achille A. Nucita, Francesco De Paolis, Antonio Franco, Francesco Strafella

We present LUMA, a convolutional neural network (CNN) pipeline for the automated detection of strong gravitational lenses in simulated astronomical imaging. The method combines a physically motivated preprocessing stage, which enhances faint arc and ring features, with a compact three-block CNN trained using class reweighting and modern learning-rate scheduling. On simulated data, the model reaches test accuracies of about $96$\% and receiver operating characteristic (ROC) area-under-the-curve (…

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astro-ph.GAastro-ph.IM2026年9月29日

Morphological Identification of Dynamical Regimes in MHD Turbulence with ScaleAware-JEPA

Mengke Zhao, Guang-Xing Li, Keping Qiu

The morphology of turbulent interstellar gas reflects the coupled action of turbulence, magnetic fields, and self-gravity, but density amplitude alone does not uniquely specify dynamical state. We use ScaleAware-JEPA to learn multiscale structural coordinates from density alone and test whether these learned coordinates organize dynamical states more clearly than density-based conditioning. Clump-like, filament-like, and diffuse-like latent neighborhoods show an ordered progression in turbulent…

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hep-phastro-ph.HE2026年9月29日

Does the High-Energy LUX--ZEPLIN Event Suggest Hyperfine Atomic Dark Matter?

Prolay Chanda, Bhaskar Das, Sagnik Mukherjee

The LUX--ZEPLIN (LZ) Collaboration has reported a nuclear-recoil candidate at $248\pm23~({\rm stat})\pm23~({\rm sys})~{\rm keV}$ in an extended high-energy search window. We investigate whether this event can arise from the hyperfine excitation of hydrogen-like atomic dark matter. For a TeV-scale dark atom, a hyperfine splitting near $340~{\rm keV}$ places xenon scattering close to the observed value by naturally selecting the high-velocity tail of the Galactic halo while suppressing the leading…

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astro-ph.GA2026年9月29日

Dynamical friction vs. subhalo heating in Cold Dark Matter haloes

Jorge Peñarrubia, Pierfrancesco Di Cintio, Eduardo Vitral, Matthew G. Walker

The orbital evolution of massive stellar systems embedded in dark matter haloes is governed by competing processes. Dynamical friction removes orbital energy, whereas fluctuations in the gravitational field generated by dark matter subhaloes inject energy through stochastic heating. We investigate the balance between these two mechanisms using analytical arguments and numerical experiments. We show that, for a given host halo and subhalo population, there exists a critical mass $M_{\rm crit}$ at…

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astro-ph.GAastro-ph.EPastro-ph.SR2026年9月29日

Testing KMTNet--PRIME Optical--Near-Infrared Source-Color Constraints in KMT-2024-BLG-0211 and KMT-2024-BLG-1522

Kansuke Nunota, Jennifer C. Yee, Takahiro Sumi, Ryusei Hamada, Ian A. Bond, Andrew Gould, Weicheng Zang, David P. Bennett et al.

We present analyses of two 2024 microlensing events, KMT-2024-BLG-0211 and KMT-2024-BLG-1522, jointly observed by KMTNet in the optical and PRIME in the near-infrared. For KMT-2024-BLG-0211, the KMTNet--PRIME $I-H$ color provides a useful constraint on the angular source radius for a short-timescale finite-source event with a giant source. The event is consistent with a low-mass stellar lens, although the weak parallax constraint leaves the lens mass and distance uncertain. For KMT-2024-BLG-1522…

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astro-ph.GA2026年9月29日

Broadband reverberation mapping of quasars at cosmic noon

Juan V. Hernández Santisteban

Broadband reverberation mapping provides a powerful tool to investigate the structure of the accretion flow around supermassive black holes. The ultraviolet region of the quasar spectrum is of particular interest, as it enables the disentanglement of the relative contributions from the accretion disc and the broad-line region to the observed variability of quasars in the local Universe. Observations of quasars at cosmic noon ($z\sim 1-2$) offer the opportunity to probe the UV emission across a d…

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astro-ph.GAastro-ph.COgr-qchep-ph2026年9月29日

Population search for dark matter spikes in megamaser rotation curves

Gonzalo Herrera

A black hole growing adiabatically inside a dark matter halo is expected to develop a dense spike, with a power-law slope between 1.5 and 2.5, depending on redshift and baryonic activity. Direct dynamical tests of this prediction are almost non-existent. Here we show that water megamaser disks offer one; their masers orbit within a parsec of the black hole and are mapped individually with very long baseline interferometry, so the enclosed mass at each radius can be read off the rotation curve. W…

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astro-ph.EP2026年9月29日

High-CO2 Climates and Observables in the Outer Habitable Zone

Daria Pidhorodetska, Edward W. Schwieterman, Thomas J. Fauchez, Martin Turbet

The habitable zone (HZ) is a fundamental concept used to guide our search for temperate exoplanets with stable surface liquid water that would sustain remotely detectable biosignatures. So far, most advanced 3D climate studies and prospective spectral simulations of HZ planets have focused on inner HZ planets that receive stellar radiation similar to Earth and would consequently maintain relatively low (e.g., hundreds of parts per million) atmospheric CO2. Here, we present a systematic investiga…

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astro-ph.EPastro-ph.GAastro-ph.IM2026年9月29日

A Bayesian Inference Framework for Binary Lens Events Fully Incorporating Higher-Order Effects

Kansuke Nunota, Kento Masuda

Higher-order effects, such as microlensing parallax and lens orbital motion, are essential for characterizing the physical properties of microlensing planetary systems including their masses and distances. In practice, higher-order effects are often included in light-curve modeling only when their signals are strong, because their inclusion in weakly constrained cases tends to drive the inferred parameters toward regions of parameter space that are disfavored by standard Galactic models. This bi…

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astro-ph.GAastro-ph.CO2026年9月29日

An Ionized Superstructure at Cosmic Dawn Revealed by a Foundation Model for Astrophysical Research

Minghao Yue, Yongda Zhu, Jiani Ding, Xiaohui Fan, Yufeng Luo

The spatial structure of cosmic reionization remains poorly constrained. Using a foundation model trained for James Webb Space Telescope datasets, we identify a luminous galaxy at redshift $z=7.567$ showing strong Ly$α$ transmission at $z=6.80\pm0.07$. The transmission extends over $210.5^{+55.7}_{-53.5}$ comoving megaparsecs, indicating an ionized superstructure with hydrogen neutral fraction $x_{\rm HI}=(2.07^{+0.29}_{-0.30})\times10^{-6}$, in an epoch when the cosmic mean neutral fraction is…

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astro-ph.HE2026年9月29日

Combined constraints on the diffuse flux of cosmic neutrinos between 10^16 eV and 10^26 eV

S. V. Troitsky

Experimental constraints on the diffuse neutrino flux above the PeV range have been obtained with Cherenkov neutrino telescopes, air-shower arrays, radio detectors in and above polar ice, and radio observations of the Moon. Published results use different flavor, energy-bin, and statistical conventions, so their flux limits cannot be combined directly. We reconstruct energy-dependent exposures of the published searches and place them in a common convention for the total all-flavor $ν+\barν$ flux…

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astro-ph.IMgr-qc2026年9月29日

ECLIPSE-X: Plate-Scale Calibration as the Binding Constraint on Relativistic Astrometry with Spacecraft Navigation

Pedro J. Llanos

Precision stellar astrometry near the Sun can constrain the parametrized post-Newtonian (PPN) parameter gamma through gravitational light deflection. This study develops ECLIPSE-X, a localized multi-frame estimation architecture in which one persistent relativistic parameter is estimated simultaneously with frame-dependent spacecraft line-of-sight and roll states, separated by their differing spatial signatures and by the persistence of gamma across frames. The aim is not a competitive determina…

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astro-ph.COastro-ph.GAastro-ph.IM2026年9月29日

Everything Everywhere All At Once: A Hierarchical Framework for Mapping Anisotropies in the Local Universe

Aryan Bansal, Edward N. Taylor, Michelle Cluver, Matthew Colless

We present a Bayesian hierarchical forward model for mapping the local luminosity-density field from heterogeneous redshift surveys. By dividing the survey volume into angular cells and redshift shells, we model the observed galaxy distribution directly in apparent-magnitude and redshift space. This allows us to infer cell-level luminosity functions and densities while preserving each survey's unique selection function. Simultaneously, the ensemble of cells constrains the cosmic-mean luminosity…

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math.NAastro-ph.HE2026年9月29日

An Energy-Conserving Unstaggered Electromagnetic-Potential Particle-in-Cell Method, Part II: Fully Relativistic Formulation with an Adapted Higuera--Cary Pusher

Andrew Christlieb, Luis Chacon, Sining Gong

We develop a fully relativistic extension of the energy-conserving, unstaggered electromagnetic-potential particle-in-cell method introduced in our earlier nonrelativistic work. As in the nonrelativistic generalized-momentum formulation, the fields are advanced by a Crank--Nicolson discretization of the Lorenz-gauge potential equations, the current is deposited from particle orbits, and charge is advanced through the discrete continuity equation. The new ingredient is a generalized-momentum adap…

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astro-ph.SRastro-ph.IM2026年9月29日

Properties of Circumfacular Regions derived from H$α$ and Ca II K synoptic observations of the Sun

Serena Criscuoli, Andrea Diercke

Circumfacular regions are dark chromospheric structures surrounding magnetic regions whose properties and contribution to solar activity diagnostics remain poorly understood. We investigate their photometric and geometric properties using full-disk H$α$ and Ca II K observations acquired by the Chromospheric Telescope (ChroTel) from 2012 to 2020, spanning the maximum and declining phases of solar cycle 24 and the beginning of cycle 25. We develop an automated segmentation algorithm to identify ci…

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astro-ph.IM2026年9月29日

Multi Kernel Gaussian Process Guiding: Predictive Correction for Mounts with Several Gear Stages

Rumen G. Bogdanovski

Gaussian process (GP) based predictive periodic error correction, introduced by Klenske et al., learns a telescope mount's periodic tracking error online and applies the correction before the error is observed, removing the reaction lag inherent in purely reactive autoguiders. The published model uses a single periodic kernel and therefore represents the error of one gear stage: any repeating shape at one period, harmonics included, but only one period. Mounts with more than one reduction stage…

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gr-qcastro-ph.HE2026年9月29日

Computing gravitational radiation from highly eccentric bound binaries in the small-mass-ratio limit

Diego Andrés Rivera Orona, Scott A. Hughes

Precise strong-gravity models describing the evolution of bound compact binary systems provide important information about the gravitational radiation such binaries generate and how they evolve due to the radiation's backreaction. The limit of very high eccentricity, $e \to 1$, is challenging to model: frequency-domain techniques require many harmonics to accurately describe radiation in this limit, and time-domain techniques can be slow to converge due to the systems' long timescales. Many rece…

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astro-ph.HE2026年9月29日

JWST/MIRI Spectroscopy of the Quiescent Black Hole X-ray Binary XTE J1118+480: Constraints on Jet and Circumbinary Dust Contributions to the Mid-infrared Emission

Zihao Zuo, Elena Gallo, Nuria Calvet, Richard M. Plotkin, David M. Russell, Gabriele Cugno, Rob Fender, Fraser Lewis et al.

We report on JWST/MIRI low-resolution spectroscopy ($5$-$12 μ$m) and imaging ($15$-$25 μ$m) of the black hole X-ray binary XTE~J1118+480 in quiescence, at an X-ray luminosity nine orders of magnitude sub-Eddington, together with contemporaneous optical monitoring and a radio upper limit of $4.5~μ$Jy at 6 GHz. With the donor subtracted, the $5$-$12 μ$m continuum is curved, turning over near $6~μ$m; a single power law is rejected in favor of a $764\pm 9$ K blackbody. Longward of the turnover the s…

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