研究動向

astro-ph.GA2026年10月22日

Rest-frame Ultraviolet Variability of Quasars in the Cosmic Himalayas Overdensity

Jiaqi Lin, Zhenya Zheng, Bin Ma, Yongming Liang, Lin Long

Some high-redshift overdensities show an enhanced incidence of AGNs, suggesting that large-scale environment may influence supermassive black hole fuelling and triggering. Whether environment also affects AGN variability remains unclear.Using the Cosmic Himalayas (CH), an extreme concentration of 11 type 1 quasars at z=2.16-2.20, we investigate possible offsets in rest-frame ultraviolet variability relative to quasars with comparable redshifts, black hole masses, and Eddington ratios.We construc…

詳細を見る →

physics.space-phphysics.geo-phphysics.plasm-ph2026年10月22日

First Results of Calculation of the Dayside Magnetopause Reconnection Rate with TRACERS

D. E. da Silva, L. J. Chen, B. Burkholder, C. J. Martin, B. Michotte de Welle, I. DesJardin, S. A. Fuselier, K. J. Trattner et al.

Quantifying the rate of reconnection remains a key challenge in the study of geomagnetic storms. In this study, we present the first results from the new Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) mission to calculate the reconnection rate from dispersed ion populations measured in the cusp, using previously developed methodology. We study ion dispersion events in two storms. During the first storm, which occurred on September 30, 2025, 21 dispersion events…

詳細を見る →

astro-ph.EP2026年10月22日

Quasi-Localization of Short-Wavelength Perturbations in Softened Laplace-Lagrange Chains

Konstantin Batygin, Eiichiro Kokubo

We examine the long-term evolution of localized eccentricity perturbations in a softened Laplace-Lagrange chain. The secular coupling between mass elements is long-ranged, suggesting that any disturbance imposed at a single radius should disperse rapidly across the chain. We show that this expectation fails once the secular interaction is regularized by a finite softening length $β$: while broad eccentricity profiles propagate smoothly, as textbook secular theory anticipates, narrow profiles rem…

詳細を見る →

astro-ph.COastro-ph.HEhep-ph2026年10月22日

Same Events, Weaker Bound: Model Dependence in Magellanic Microlensing Limits on Primordial Black Holes

David Morales-Zapien, Lucas Brown, Stefano Profumo

OGLE microlensing of the Magellanic Clouds sets the leading bounds on primordial black holes (PBHs) as dark matter from $10^{-8}$ to $10^{3}\,M_\odot$. Holding the detected events and survey efficiencies fixed, we show that changes to the Milky Way halo, the stellar lens populations and the Large Magellanic Cloud halo, each motivated by recent data, weaken the published strict 20-year bound by up to $\simeq6$, and by over an order of magnitude in an extreme stress test. With primordial clusterin…

詳細を見る →

astro-ph.GAastro-ph.SR2026年10月22日

A Potential New Dimension of Astrophysical Aromatic Functionalization: Phosphaethynyl (CP) Derivatives

Reace H. J. Willis, Vincent J. Esposito, Thomas H. Speak, Ilsa R. Cooke, Ryan C. Fortenberry

Quantum chemical computations outline a thermodynamically viable, low-temperature, gas-phase formation pathway for phosphaethynyl cyclopropenylidene ($c$-C$_3$HCP), resulting from cyclopropenylidene ($c$-C$_3$H$_2$) and the phosphaethynyl (CP) radical. Given the detections of both $c$-C$_3$H$_2$ and the CP radical toward circumstellar shells along with the provided reaction pathway, $c$-C$_3$HCP is a potentially present astro-molecule which could be searched for in phosphorus rich environments.…

詳細を見る →

astro-ph.HEastro-ph.EPastro-ph.SR2026年10月22日

Simulations of a Conducting Sphere Moving through Magnetized Plasma II: Effect of Internal Magnetic Fields and Enhancement of Alfvénic Drag

Nicholas Corso, Dong Lai

Magnetic interaction between astrophysical objects can play an important role and produce electromagnetic radiation in various systems, ranging from planet-moon and star-planet systems to binary compact objects. We extend our previous numerical study of an ideal magnetized plasma flowing past a conducting sphere to the case where the sphere is magnetized. Such a flow generates magnetic disturbances and produces a drag force on the sphere. We examine the drag coefficient as a function of the stre…

詳細を見る →

astro-ph.EP2026年10月22日

Ellipsoidal Modeling Framework for TNOs: the triaxial shape of (50000) Quaoar and its implications for Weywot and the dynamical environment

Giuliano Margoti, Felipe Braga Ribas, Eros Gradovski, Gustavo Madeira, Chrystian L. Pereira, Jose L. Ortiz, Bruno Sicardy

The three-dimensional shapes of Trans-Neptunian Objects (TNOs) are notoriously difficult to determine due to their slow orbital motion and minimal variations in aspect angle over human timescales. To overcome this geometric degeneracy, we developed a versatile modeling framework capable of deriving ellipsoidal shapes by simultaneously combining stellar occultations and rotational light curves, including parameterizations of localized surface albedo. We applied this methodology to the large TNO (…

詳細を見る →

astro-ph.GAastro-ph.SR2026年10月22日

JWST observations of the planetary nebula NGC 6302 IV: PAH spectral characteristics, formation and evolution

Nicholas Clark, Els Peeters, Jan Cami, Mikako Matsuura, Alexander G. G. M. Tielens, Patrick J. Kavanagh, Michael J. Barlow, Joel Kastner et al.

Polycyclic aromatic hydrocarbons (PAHs) and carbonaceous dust have been observed in Oxygen-rich planetary nebulae (PNe), yet their formation and evolution in these environments is an open question. We aim to study the formation and evolution of the PAHs in the O-rich PN NGC 6302, by characterizing the PAH emission throughout this object. We obtained JWST MIRI IFU spectroscopic observations of NGC 6302 pointed at its central source. From these, we extract four template spectra that are representa…

詳細を見る →

astro-ph.HE2026年10月22日

Chandra and Multiwavelength Study of Pevatron Candiate HESS J1702-420A

Hui Yang, Yichao Lin, Jeremy Hare, Seth Gagnon, Oleg Kargaltsev

Aims: HESS J1702-420A is a promising Galactic PeVatron candidate whose physical nature remains unknown. Previous XMM-Newton observations revealed hard, apparently extended X-ray emission from XMMU J170147.3-421407, offset from the center of the TeV source, suggesting a possible pulsar wind nebula (PWN) association. We aim to resolve its X-ray morphology, investigate compact-object candidates in the field, and assess their possible association with HESS J1702-420A. Methods: We obtained three new…

詳細を見る →

astro-ph.IMastro-ph.EP2026年10月22日

The Pandora SmallSat: post-launch operations and mission update

Trevor O. Foote, Elisa V. Quintana, Jessie L. Dotson, Knicole D. Colón, Thomas Barclay, Pete Supsinskas, Jordan Karburn, Dániel Apai et al.

The Pandora SmallSat is a NASA flight project designed to study the atmospheres of exoplanets. Transmission spectroscopy of transiting exoplanets provides our best opportunity to identify the makeup of planetary atmospheres in the coming decade, and is a key science driver for HST and JWST. Stellar photospheric inhomogeneity due to star spots, however, has been shown to contaminate the observed spectra in these high-precision measurements. Pandora will address the problem of stellar contaminatio…

詳細を見る →

astro-ph.IMastro-ph.EP2026年10月22日

A Technical Reanalysis of the Viking Carbon Assimilation-Pyrolytic Release Experiment

Jan Spacek, Clay A. Abraham, Steven A. Benner

The 1976 Viking Carbon Assimilation-Pyrolytic Release (CAPyR) experiment tested whether carbon from $^{14}$CO$_2$ and $^{14}$CO entered Martian soil during a 120-hour incubation in a form retained during a 120 $^\circ$C purge but released by pyrolysis at 635 $^\circ$C. Untrapped radioactivity was measured as Peak 1; material retained in an organic vapor trap was oxidized and measured as Peak 2. Net Peak 2 was intended to represent synthesized reduced organic carbon. Seven of nine usable incubati…

詳細を見る →

astro-ph.GA2026年10月22日

Optical and near-infrared s-process abundance scales in the Galactic disc

Andrés E. Piatti

A discrepancy has recently emerged between optical and near-infrared (NIR) s-process abundance scales, particularly for Neodymium (Nd). We investigated this issue using a direct cross-match between the optical Gaia-ESO Survey (DR5) and NIR SDSS-V/MWM (DR19). While atmospheric parameters and Cerium (Ce) abundances exhibit robust 1:1 correlations, Nd displays a systematic X-shaped vertical stretching. Our analysis reveals that the SDSS-V pipeline expands intrinsic Nd variations by a scaling factor…

詳細を見る →

astro-ph.GA2026年10月22日

Optical-Infrared Extinction Variation in Nearby Molecular Clouds

Marshall Hobson-Ritz, Sarv Parteek Singh, Eddie Schlafly, Lee Mundy, Alberto Bolatto

The dust extinction curve is an important probe of the properties of dust grains, particularly their size distribution. The properties of dust grains are expected to change significantly in dense molecular clouds due to shielding from interstellar radiation and increased frequency of grain-grain and grain-gas collisions. We measure the dust extinction curve shape parameter R(V) in 9 nearby, dense molecular clouds using data from the APOGEE spectroscopic survey, in combination with ten-band photo…

詳細を見る →

astro-ph.SR2026年10月22日

Solar Photospheric Flows and the Origin of Active Regions

Alexander V. Getling

The early evolutionary stages of some active regions (ARs) are analysed with the aim of resolving one of the paramount-importance problems of heliophysics: what plays a primary, active role in the formation of active regions and sunspots---magnetic fields or motion of solar plasma? In particular, the first view underlies the popular model of rising $Ω$-shaped, twisted flux-tube loop of strong magnetic field. In this study, optical images obtained by the Helioseismic and Magnetic Imager (HMI) of…

詳細を見る →

physics.plasm-phastro-ph.HEastro-ph.SR2026年10月22日

Evolution of Jeans instability in nonthermal magnetized complex plasmas

Dipankar Ray, Pralay Kumar Karmakar, Bharati Kakad, Amar Kakad

The classical Jeans instability framework provides a conceptual foundation for understanding self-gravitational collapse and subsequent star formation in interstellar environments. However, cosmic plasmas are inherently magnetized and frequently collisionless, exhibiting significant departures from local thermodynamic equilibrium. While linear theories predict initial instability thresholds, they fail to track the long-term nonlinear runaway dynamics. We present a fluid simulation investigating…

詳細を見る →

astro-ph.EPastro-ph.IM2026年10月22日

OGLE-2012-BLG-0563: Relative Proper Motion Constraint from Keck Follow-up finds the correct Lens

Aparna Bhattacharya, David P. Bennett, Jean Phillippe Beaulieu, Ian A. Bond, Kansuke Nunota, Jessica R. Lu, Joshua W. Blackman, Andrew A. Cole et al.

We present Keck/NIRC2 adaptive optics imaging results of planetary microlensing event OGLE-2012-BLG-0563. We find that the OGLE-2012-BLG-0563L planetary system consists of a 1.12 +/- 0.09 Jupiter-mass planet orbiting a 0.81 +/- 0.04 solar-mass host star at a distance of 5.49 +/- 0.56 kpc from the Sun. This event has a lens-source separation of 23.28 +/- 0.48 mas, which is the smallest lens-source separation measured to date with Keck AO data. We find that the incorrect solution - which identifie…

詳細を見る →

astro-ph.GAastro-ph.CO2026年10月22日

The PAU Survey: Active galactic nucleus galaxies in galaxy pairs

F. Duplancic, M. Siudek, D. Navarro-Gironés, E. J. Gonzalez, F. Rodriguez, S. Alonso, I. V. Daza-Perilla, D. G. Lambas et al.

Aims. Leveraging the high-precision photometric redshifts of the Physics of the Accelerating Universe Survey (PAUS), we aim to investigate the connection between active galactic nuclei (AGNs) and galaxy pairs up to redshifts of $\sim1.0$. Methods. We identified 16,824 galaxy pairs with projected separations of $r_p < 100$ kpc and radial-velocity differences of $ΔV < 3500$ km s$^{-1}$. AGNs were selected by cross-matching PAUS galaxies with multi-wavelength AGN catalogues, yielding 270 AGNs in pa…

詳細を見る →

astro-ph.GA2026年10月22日

The LBT Y$_{\rm p}$ Project VI: Gas-Phase Chemical Abundance Patterns of Metal-Poor Nebulae

Noah S. J. Rogers, Evan D. Skillman, Richard W. Pogge, Erik Aver, Miqaela K. Weller, Danielle A. Berg, John J. Salzer, John H. Miller et al.

Through a combined rest-optical and NIR observing campaign, the Large Binocular Telescope Primordial He Abundance ($Y_{\rm p}$) Project has delivered a precision measurement of $Y_{\rm p}$. Given the stringent requirements to measure gas-phase He abundances, the optical spectra contain emission features from a plethora of metals in the Interstellar Medium (ISM). We present gas-phase N, O, Ne, S, Cl, Ar, K and Fe abundance patterns in 62 low-metallicity nebulae. We assess ionization correction fa…

詳細を見る →

astro-ph.HEastro-ph.GA2026年10月22日

Nuclear Millimeter Continuum Emission in Radio-Quiet Active Galactic Nuclei: an ALMA Spectral and Variability Study

Sophie M. Venselaar, Claudio Ricci, Yoshiyuki Inoue, Chin-Shin Chang, Akihiro Doi, Noemi Barnier, Taiki Kawamuro, Susanne Aalto et al.

Unresolved millimeter (mm) emission is observed in radio-quiet (RQ) Active Galactic Nuclei (AGN), but its physical origin remains debated. Self-absorbed synchrotron emission from the compact X-ray corona is one of the leading candidates. Previous support for this coronal synchrotron origin has mainly been based on variability and spectral indices in a few RQ AGN, with a lack of (quasi-)simultaneous broadband data for larger samples. We present Atacama Large Millimeter/sub-millimeter Array (ALMA)…

詳細を見る →

astro-ph.GAastro-ph.COastro-ph.HE2026年10月22日

The black hole-galaxy correlations of the 12 micron local AGN sample: a NuSTAR perspective

M. Gliozzi, L. Spinoglio, J. A. Fernandez-Ontiveros, M. A. Malkan, J. K. Williams, M. Young. A. D. Oxley, S. Satyapal

The M-sigma correlation of inactive galaxies plays a crucial role in estimating the black hole mass (MBH) in active galactic nuclei (AGN): 1) it is used to calibrate the reverberation mapping (RM) method; 2) the RM is the basis of the single epoch method, the most-used technique to determine MBH of broad-line AGN; and 3) in narrow-line AGN, MBH is often directly inferred from the M-sigma correlation. The main goal of this work is to test whether the M-sigma relation calibrated from inactive gala…

詳細を見る →

astro-ph.IM2026年10月22日

Astro2Method: Benchmarking LLMs on Machine Learning Method Selection in Astronomy

Xingzhong Fan, Hangfeng He, Fatemeh Nargesian

Machine learning (ML) is increasingly used in astronomy, but choosing a suitable method for a scientific problem often requires expertise in both astronomy and ML. Large language models (LLMs) could help astronomers make such choices, yet this ability remains underexplored in existing benchmarks. We introduce Astro2Method, a benchmark of 500 expert-reviewed binary questions from 346 astronomy papers (2024/01-2026/06), based on clear performance differences and complete (Easy) or partial (Hard) e…

詳細を見る →

astro-ph.HEastro-ph.GAastro-ph.SR2026年10月22日

Gone Without a Bang: A Search for Failed Core-Collapse Supernovae in ZTF and Predictions for Rubin and Roman

Shion Murakawa, Paul Draghis, Kevin Burdge, Ore Gottlieb, Aaron Householder, Emma Chickles

The core-collapse of massive stars (${\geq}10\ \rm M_\odot$) usually takes the form of a supernova, but in some cases may lead to a direct collapse, leading to a failed core-collapse supernova (FccSN). Wide-field time-domain surveys, such as the Zwicky Transient Facility (ZTF), are a useful tool to find such ``disappearing" stars. We use a piecewise linear function model to search the entire ZTF optical photometric catalog for FccSNe, yielding 125 ``faders" that dip significantly with a flat top…

詳細を見る →

astro-ph.GAastro-ph.CO2026年10月22日

The THESAN-ZOOM project: the delayed rise of Lyman continuum escape fractions in bursty high-redshift galaxies

Parth Mehrotra, Aaron Smith, Yuan Bian, William McClymont, Ewald Puchwein, Rahul Kannan, Laura Keating, Xuejian Shen et al.

The ionizing radiation that galaxies release into their surroundings depends on whether efficient Lyman continuum (LyC) escape coincides with strong photon production. Stellar feedback can open escape paths as the source population fades, linking the escaping radiation to a galaxy's recent history. We investigate this timing in thirteen high-redshift (z > 3) target haloes from the THESAN-ZOOM radiation-hydrodynamic simulations, post-processed with COLT radiative transfer and sampled at ~10 Myr i…

詳細を見る →

astro-ph.SRastro-ph.GA2026年10月22日

AGB-star Mass Transfer Products in Stellar Streams as Tracers of Density in Dissolved Star Clusters

Newlin C. Weatherford, Madeleine McKenzie, Sam A. Usman

The least dense globular clusters (GCs) appear to host the highest fractions of stars with chemical signatures of mass transfer from asymptotic giant branch (AGB) companions. Recent observations suggest the fraction may be even higher in stellar streams that are debris of tidally disrupted (preferentially low-density) GCs. We explore whether this is attributable to lower encounter rates in less-dense GCs allowing more of the relevant binaries to survive dynamical hardening, or outright disruptio…

詳細を見る →

astro-ph.SRastro-ph.GAastro-ph.HE2026年10月22日

Charting the Galactic Underworld II: Strategies for Identifying BHs and NSs with LISA

Tom Wagg, Frank E. Prince, Katelyn Breivik, Kira Baasch, Jorie McDermott, Michael Zevin

Stellar-mass black holes (BHs) and neutron stars (NSs) observed by space-based gravitational-wave detectors offer constraints on binary stellar evolution that are complementary to those from ground- based detectors. The Laser Interferometer Space Antenna (LISA) is expected to detect hundreds of double compact objects (DCOs) containing a BH or NS, but distinguishing these sources from the far more numerous double white dwarfs (WDWDs) may prove challenging. We use adaptive importance sampling with…

詳細を見る →

hep-phastro-ph.COastro-ph.HE2026年10月22日

Variable-phase methods and data for long-range scattering

Marcos M. Flores, Kalliopi Petraki, Thomas Pignard

Long-range interactions play an important role in dark-matter phenomenology, affecting the relic abundance, indirect-detection signals, and structure formation on galactic scales. Reliable predictions often require nonperturbative solutions of the Schrödinger equation over broad parameter ranges and many partial waves. We present a numerical framework based on the variable-phase method, which recasts the radial Schrödinger equation as a system of first-order equations and allows both regular and…

詳細を見る →

astro-ph.HEastro-ph.GAhep-th2026年10月22日

The deepest X-ray view of a kiloparsec scale jet at z=6.1

Fabio A. Meanti, Luca Ighina, Alberto Moretti, Kyra Bettwy, Alessandro Caccianiga, Thomas Connor, Fabrizio Tavecchio, Silvia Belladitta et al.

The mechanism responsible for the high-energy emission observed in kiloparsec-scale jets across cosmic time remains poorly understood. The relativistic jet associated with the z=6.1 AGN PSO J030947.49+271757.31 is the highest-redshift large-scale jet currently resolved in X-rays, providing a unique opportunity to study these structures. We present new Chandra observations, combined with archival data, for a total exposure of 360 ks. The increased exposure allowed us to resolve the extended X-ray…

詳細を見る →

astro-ph.EP2026年10月22日

The physical and chemical structure of Titan's upper atmosphere: energy balance, photochemistry and Jeans escape

Sudeshna Boro Saikia, Jonathan Tennyson, Shuchen Ji, Nils-Martin Robeling, Ivan Stanković, Gwenaëlle Van Looveren, Simon Schleich, Colin P. Johnstone et al.

Titan's upper atmospheric layers provide a unique opportunity to study how photochemistry, photoionisation, haze microphysics and escape processes shape its atmospheric chemical structure, providing a unique benchmark for understanding these processes in exoplanets. Using a 1D first-principles approach, we extend the Kompot model to simulate Titan's upper atmosphere and investigate its thermal and chemical structure, and Jeans escape. We performed self-consistent simulations of Titan's upper atm…

詳細を見る →

hep-phastro-ph.HE2026年10月22日

$γ$hosts from the past: reheating neutron stars with supernova-sourced ALPs

Debajit Bose, Sougata Ganguly, Tanmoy Kumar, Nirmal Raj

Axion-like particles (ALPs) can be copiously produced in the hot and dense environment of a core-collapse supernova. If their mass is within an order of magnitude of the supernova temperature, a non-negligible fraction of them will remain gravitationally bound to the neutron star remnant. This basin of ALPs can then decay to photons over the lifetime of the neutron star, thereby reheating it. Using the measured luminosities of several neutron stars, we close multiple windows in ALP parameter spa…

詳細を見る →

astro-ph.EP2026年10月22日

The coupled impacts of atmospheric dynamics and cloud microphysics on hot Jupiter atmospheres. I. An application to WASP-43b

Emeline F. Fromont, Thaddeus D. Komacek, Peter Gao, Hayley Q. Beltz, Sarah E. Moran, Arjun B. Savel, Julia Cottingham, Isaac Malsky et al.

Understanding the influence of cloud-circulation feedback on planetary climates is crucial to interpreting solar system and extrasolar planet observations. Hot Jupiter phase curve observations have reported westward optical phase curve offsets and weak absorption features, which may be explained by the presence of clouds. JWST observations have also revealed tentative silicate cloud absorption features in emission and transmission spectroscopy. While a number of 3D atmospheric dynamics models of…

詳細を見る →