研究動向

astro-ph.SR2026年9月22日

A VLBA survey of radio stars in the Orion Nebula Cluster: III. Inter-epoch variability analysis

E. T. O'Kelly, J. Forbrich, S. A. Dzib, J. Vargas-González

We present a multi-epoch Very Long Baseline Array (VLBA) survey of radio sources in the Orion Nebula Cluster (ONC), updating the detection statistics and investigating inter-epoch variability. The dataset comprises eight C-band (4-8 GHz) epochs targeting 575 radio sources previously identified in deep Very Large Array surveys. VLBA observations result in resolutions of milliarcseconds and are only sensitive to high brightness temperatures meaning only non-thermal emission is observed. We detect…

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astro-ph.EPastro-ph.GAastro-ph.SR2026年9月22日

NGTS clusters survey - VII. An Enigmatic Short-Period Circumsecondary Disk Candidate in Orion

Niamh Mallaghan, Ernst J. W. de Mooij, Christopher A. Watson, Edward Gillen, Matthew Kenworthy, Louise D. Nielsen, David R. Anderson, Matthew P. Battley et al.

Young stellar systems provide key insights into the processes governing star/planet formation, often exhibiting complex and evolving photometric variability. In this paper, we present an analysis of the object around NOI 105872, observed by the Next Generation Transit Survey (NGTS) to eclipse a young ($4.1\pm0.4$ Myr) M-type star in the Orion Nebula Cluster. The system displays deep, asymmetric eclipses with a period of $\sim0.69$ days, alongside variability in morphology. We combine photometric…

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astro-ph.HE2026年9月22日

Neutrino Astronomy at High Energies - An Experimental Review

Christian Spiering

Neutrino astronomy at high energies is an emerging field but still in a state of infancy. It is barely a dozen years ago that a diffuse flux of extraterrestrial neutrinos with energies in the TeV and PeV ranges was detected and even fewer that first individual sources could be identified. A new window to the universe has been opened after four decades of efforts to realize the gigantic instruments that made that breakthrough possible. This review describes the road towards the present, reviews t…

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astro-ph.EP2026年9月22日

Molecules in the shadows of the protoplanetary disk HD 143006: Evidence for C/O $\gtrsim 1$ from simultaneously modeling fourteen ALMA lines

S. E. van Terwisga, P. Woitke, A. M. Weiss, A. D. Bosman, L. Trapman

The inner disk of the T Tauri star HD 143006 is inclined and casts a broad shadow on a large portion of the outer disk. We use this extraordinary geometry to study the impact of stellar ultraviolet (UV) irradiation on disk chemistry, temperature, and line formation. We present new ALMA observations of this disk in CO, $^{13}$CO, C$^{18}$O, CN, HCN, HCO$^+$, CS and C$_3$H$_2$ and combine these with previously-published data to get a rich dataset, which is modeled with ProDiMo models for the illum…

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astro-ph.EP2026年9月22日

Transport and Thermochemical Kinetics of Alkali Species in Hot Jupiter Atmospheres: Implications for Magnetic Models

D. A. Christie, T. M. Evans-Soma, N. J. Mayne, E. Hébrard, M. Zamyatina, J. E. Owen, K. Kohary

Interactions between the planetary magnetic field of a hot Jupiter and the winds within its atmosphere are moderated by the electron and ion abundances. For a solar metallicity atmosphere at pressures between 10 and $10^{-4}$ bar, the primary sources for these charged species are expected to be the potassium and sodium atoms, and models of magnetic effects in hot Jupiter atmospheres have typically assumed that charged species exist within the atmosphere in their equilibrium abundances. In this w…

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astro-ph.HE2026年9月22日

Inelastic scattering effects on polarization predictions for cold and warm atmospheres in the X-rays

J. Podgorný, L. Marra, M. Dovčiak, R. Taverna, R. W. Goosmann, M. Gupta, F. Marin, G. Matt et al.

X-ray polarization models of accreting compact objects often assume the so-called Chandrasekhar-Sobolev polarization prescription for elastic Thomson scattering in electron-scattering semi-infinite atmospheres. In this letter, we examine the effects of inelastic Compton scattering. We assume homogeneous slabs of cold and warm (up to 1 keV) electrons. We use a Monte Carlo approach. We discuss the polarization difference arising in the X-rays between the elastic and inelastic scattering assumption…

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astro-ph.IM2026年9月22日

Testing deep learning techniques for event reconstruction in pair-production gamma-ray telescopes

Mattia Maniscalco, Valentina Fioretti, Nicolò Parmiggiani, Andrea Bulgarelli, Carolyn A. Kierans, Adrien Laviron, Gabriele Panebianco, Alessio Aboudan et al.

In the development of next-generation tracking detectors for gamma-ray space observations, the integration of advanced deep learning techniques into event reconstruction algorithms is a promising approach for improving the performance of the mission, reducing systematic uncertainties and maximizing the scientific output. In this study, we investigate the application of deep learning techniques such as Graph Neural Networks (GNNs) for the identification and reconstruction of particle tracks resul…

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astro-ph.HEgr-qc2026年9月22日

Dense Dump Codec: Error-Controlled, Random-Access Compression of GRMHD Time Series for Slow-Light Radiative Transfer

Zelin Zhang, Zhenyu Zhang, Bin Chen

Black-hole movies provide a unique venue to study the time evolution of accreting plasma. Modeling this evolution with slow-light radiative transfer requires closely spaced simulation outputs, because the plasma changes as light propagates through it. Saving these outputs in full is costly, whereas sparse sampling introduces time-interpolation errors. We present the Dense Dump Codec (DDC), a compression method for dense GRMHD time series. DDC stores exact anchor states and compactly represents t…

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astro-ph.HEgr-qc2026年9月22日

KPolaris: GPU-accelerated Polarized Radiative Transfer in General Relativity

Zelin Zhang, Bin Chen

Polarized black-hole images carry information about both the magnetized plasma and the curved spacetime through which the radiation propagates. We present KPolaris, an open-source GPU-accelerated general-relativistic polarized radiative-transfer code built on the Kokkos framework. It supports analytic plasma models and GRMHD simulation data, with both fast-light and slow-light radiative transfer. The code also provides diagnostics that connect image structure to the emitting plasma and to propag…

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astro-ph.SR2026年9月22日

Are there really some eccentric eclipsing binaries having orbital periods below 1 d?

P. Zasche, M. Wolf

The stellar binary systems are classical tools for studying dynamics, and tidal circularization is one of the processes taking place in these. During the last few years, several dozen systems have been published supposedly having orbital periods shorter than 1 d, and have also been published as having eccentric orbits. Such a configuration is due to their spatial closeness, and the tides very improbable. Therefore, we performed a thorough analysis of all these eclipsing binaries (>140), showing…

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astro-ph.HE2026年9月22日

Einstein Probe discovery of the magnetar EP J223759.5+531421

N. Rea, F. Coti Zelati, A. Borghese, Y. L. Wang, H. Yang, X. Mao, C. -Y. Dai, E. Arrigoni et al.

We report the discovery and early outburst evolution of the new Galactic magnetar EP J223759.5+531421, detected by the Einstein Probe Wide-field X-ray Telescope on 2026 June 28. Follow-up observations with Einstein Probe, XMM--Newton, NuSTAR, SVOM, and IXPE revealed coherent X-ray pulsations at P ~ 6s and an average period derivative of Pdot ~ 2.8x10^{-12} s/s. These values imply a nominal polar dipolar magnetic field of B_dip ~ 2.6x10^{14} Gauss and a characteristic age of tau_c ~ 34 kyr, altho…

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astro-ph.SRastro-ph.GA2026年9月22日

Spectroscopic Study of the Circularly Polarised Radio Source TYC 2834-1385-1: An Active Binary

Tamara A. S. Bleeker, Alexander Hoogerbrug, Elise Koo, Rudy Wijnands, Joseph R. Callingham

Close binaries with active chromospheres have recently been shown to emit circularly polarised radio emission at low frequencies, motivating detailed studies of their orbital properties. We present high-resolution ($R=85,000$) optical spectroscopy of TYC 2834-1385-1, a previously unclassified radio source, obtained with the HERMES spectrograph on the Mercator Telescope. We identify the source as a double-lined spectroscopic binary and measure radial velocities from both metallic absorption and C…

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astro-ph.IM2026年9月22日

Options for Compression of radio interferometry data: lossy compression of visibilities and lossless compression of uv-visibility grids for the MHONGOOSE survey

Richard Dodson, Jonghwan Rhee, W. J. G. de Blok, Martin Meyer, Alexander Williamson, Daniel Mitchell, Kristóf Rozgonyi, María J. Rioja et al.

Next generation radio astronomy telescopes are challenging existing data reduction paradigms. With ever more antennas, larger bandwidths, and sometimes multiple primary beams, they often generate more observed data products than can readily be stored long-term. Thus, data storage becomes a major cost driver and processing constraint. In this paper, we test two methods of addressing this problem: grid-stacking, a two-stage lossless compression solution; and the lossy compression of the raw visibi…

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astro-ph.HE2026年9月22日

IXPE observation of the new magnetar source EP J223759.5+531421

Roberto Taverna, Lorenzo Marra, Roberto Turolla, Ruth M. E. Kelly, Silvia Zane, Alice Borghese, Francesco Coti Zelati, Paolo Esposito et al.

We report on the detection of polarized X-ray emission from the new Galactic magnetar EP J223759.5+531421, discovered by the Einstein Probe Wide-field X-ray Telescope on 2026 June 28. The Imaging X-ray Polarimetry Explorer (IXPE) follow-up observation started on 2026 July 6 and detected the source at a (absorbed) flux of $\approx 4.5\times 10^{-11} \, \mathrm{ erg\,cm^2\,s}^{-1}$ ($2$--$7.5\, \mathrm{keV}$ range), confirming the presence of two thermally emitting regions on the star surface, wit…

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gr-qcastro-ph.HEnucl-th2026年9月22日

Gravitational Imprints of Dark Energy in Neutron Stars

O. P. Jyothilakshmi, Lakshmi J. Naik, V. Sreekanth

We investigate, for the first time, the non-radial $f$-mode oscillations of neutron stars (NSs) with a dark energy (DE) core utilising a fully general relativistic treatment. We construct the stellar profile by considering a relativistic mean field model for nuclear matter and a modified Chaplygin fluid like prescription for DE. We compute the stellar structure, $f$-mode oscillations, tidal deformability, and gravitational wave (GW) energy and strain of the NS with DE core by varying the DE equa…

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astro-ph.SR2026年9月22日

CME Kinematics with Optical Flow: Multi-Coronagraph Insights into Internal Velocity Dispersion

Pritam Das, Vaibhav Pant, Neeraj Rathore

Coronal mass ejections (CMEs) exhibit poorly understood internal velocity distributions. In this work, we introduce an optical flow-based method, DOFCAT (Dense Optical Flow CME Analysis Tool), applied to high-resolution data from ASPIICS/Proba-3 and METIS/Solar Orbiter to examine the internal velocity dispersion of different substructures within CMEs in the Middle Corona. We also introduce a Gaussian-tapered Fourier (GTF) filter that suppresses brightness artifacts in running-difference images f…

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astro-ph.GA2026年9月22日

Rest-Frame UV and Optical Structural Evolution of Narrowband-Selected Lyman-alpha Emitters at z = 2-7 with JWST/NIRCam

Ronaldo Laishram, Haruka Kusakabe, Satoshi Kikuta, Shunta Shimizu, Yusei Koyama, Tadayuki Kodama, Michaela Hirschmann, Greta Toni et al.

We present a systematic study of the rest-frame ultraviolet (UV) and optical morphologies of Ly$α$ emitters (LAEs) at $z \simeq 2$-$7$ from the SILVERRUSH multi-narrowband catalog, using JWST/NIRCam imaging from COSMOS-Web. We fit Sérsic profiles in four NIRCam filters (F115W, F150W, F277W, F444W) for LAEs spanning $\sim 2.2$ Gyr of cosmic time. LAE sizes show a mild increase from rest-frame UV to optical wavelengths, with a median optical-to-UV size ratio of $R_{e,\rm opt}/R_{e,\rm UV} = 1.14^{…

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astro-ph.HE2026年9月22日

Kink instability as a particle acceleration mechanism in X-ray binaries and the connection to the outburst cycle

Emma L. Elley, James H. Matthews, Alex J. Cooper, Fraser J. Cowie, Rob Fender

We consider whether the kink instability can explain particle acceleration in hard state 'compact' X-ray binary jets. We apply a 1D model to assess the expected growth rate of the instability for a variety of jet models, then scale results from simulations to estimate a dissipation rate for the magnetic energy in the jet. We then consider the effects of radiative cooling on the system. We find that hard state 'compact' X-ray binary jets are likely to be unstable to the kink instability within th…

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astro-ph.HE2026年9月22日

A Brief Review on the Statistical Properties of Fast Radio Bursts

Yu Sang, Hai-Nan Lin

Fast radio bursts (FRBs) are millisecond-duration radio transients of extragalactic origin, whose emission mechanisms and progenitors remain unresolved. Statistical analyses of the rapidly growing samples provide a promising means to constrain the underlying physics. In this review, we synthesize the statistical properties derived from current FRB catalogs, encompassing constraints on dispersion measure, redshift, energy/luminosity functions, repetition rate, and host-galaxy demographics. For re…

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astro-ph.EP2026年9月22日

Molecular mapping of an exoplanet with JWST: NH3 detection in the temperate super-Jupiter Epsilon Indi Ab

R. Kravtchenko, O. Berné, I. Schroetter, P. Amiot, F. Debras

Epsilon Indi Ab is currently the coldest, and one of the closest, directly imaged exoplanets (T_eff = 275 K, d=3.6 pc), offering a unique opportunity to test our understanding of the physical and chemical properties of gas giants across the full temperature range spanned by hotter directly imaged exoplanets and the cooler giants of the Solar System. We aim to characterize the atmosphere of Epsilon Indi Ab using infrared spectroscopic observations. We present JWST spectroscopic observations of Ep…

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astro-ph.GA2026年9月22日

Mass Distribution of M31 from its Rotation Curve up to 167 kpc

Hao Wu, Yang Huang, Huawei Zhang, Qikang Feng, Cheng Liu

The mass distribution of the Andromeda galaxy (M31) is fundamental for understanding its dark matter content, assembly history, and dynamical role within the Local Group. However, estimates of M31's total mass remain quite uncertain, partly because of limited dynamical constraints at large galactocentric radii. Moreover, M31's recent merger history has produced abundant tidal substructures and may have left its outer halo out of dynamical equilibrium, complicating equilibrium-based mass estimate…

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astro-ph.HEastro-ph.IM2026年9月22日

A Multi-Mission Detection Framework for High-Energy Transients: Application to a 13-year Fermi/GBM and Swift/BAT Sample

Ariel Perera, Barak Zackay, Tejaswi Venumadhav

The detection of faint high-energy transients is becoming increasingly important in time-domain and multi-messenger astronomy, particularly for identifying electromagnetic counterparts to binary neutron star mergers, high-energy neutrino events, and other weak transient phenomena. At present, the sensitivity of gamma-ray and hard X-ray searches is often limited by the detection threshold of individual instruments, leaving a population of faint transients inaccessible to single-mission analyses.…

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astro-ph.COastro-ph.HE2026年9月22日

Probing the Mass--Redshift Dependence of Binary Black Holes and its Implications for $H_0$ with GWTC-5.0

Yang Liu, Puxun Wu, Jun-Jie Wei, Xue-Feng Wu

The mass and redshift distributions of merging binary black holes (BBHs) bear imprints of their astrophysical formation channels. Whether the BH mass distribution evolves with redshift, however, remains an open question. In this paper, we employ copula functions, which describe the dependence between variables independently of their marginal distributions, to probe the dependence structure between the primary mass and the redshift of BBH mergers. We construct five population models by coupling t…

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astro-ph.IMastro-ph.EP2026年9月22日

Fitting Moving Objects in Up-The-Ramp Data with Applications to the Roman Space Telescope and JWST

Timothy D. Brandt

A moving object breaks the fundamental property of constant per-pixel count rates in an astronomical image read out up-the-ramp. In this paper, we show how to fit a moving object's path across a detector as that detector is read out nondestructively. We write the full likelihood function for every pixel subject to a constant count rate plus a time-dependent count rate due to a moving source. Assuming the moving source to be point-like and assuming the effective point-spread function to be known,…

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astro-ph.COastro-ph.IM2026年9月22日

HierArchical Wavelet Coefficients on the Sphere (HAWCS): the Scattering Transform on Spherical Maps

Arefe Abghari, Lukas T. Hergt, Douglas Scott, Raelyn M. Sullivan

Extracting Gaussian information from data is well understood, but characterizing non-Gaussianity is challenging. We introduce HAWCS, a healpy-based Python package for efficiently computing wavelet scattering transform coefficients from full-sky maps. These coefficients provide compact summary statistics that are sensitive to higher-order structure and interactions across angular scales. We test the implementation on controlled Gaussian and non-Gaussian fields and demonstrate its computational ef…

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math.DSastro-ph.EPastro-ph.IMstat.ME2026年9月22日

Identifiable Uniqueness of Impulsively Forced, Inert, and Stabilized Body Trajectories

Bo Pieter Johannes Andrée

An unusual object in the sky raises two related questions: what kind of object it is and what physical process drives its motion. Departures from a gravity-only trajectory can provide evidence, but the same apparent acceleration may be generated by distinct dynamical mechanisms. We formulate this as an identification problem and establish conditions for identifiable uniqueness among three reference classes: inert dynamics, impulsive forcing, and active stabilization such as a controlled spacecra…

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astro-ph.EPastro-ph.IM2026年9月22日

Possible Observational Survey Strategies to Maximize Exoplanet Yields: A Report from the Survey Strategies Task Group in the Exoplanet Science Yields Working Group

Natasha Latouf, Corey Spohn, Kevin Fogarty, Chris Stark, Dmitry Savransky n=and Eleonora Alei, Anthony Boccaletti, Gagandeep Kaur, Avi Mandell et al.

We present a variety of possible observational sequences from planet detection to characterization (i.e., survey strategies) for the initial exoEarth detection and characterization survey phase of the Habitable Worlds Observatory. An array of survey strategies were collated by the HWO Exoplanet Survey Strategies Task Group; by investigating and comparing expected resultant exoEarth yields for multiple survey strategies, we can better understand the most efficient strategy to characterize multipl…

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astro-ph.SR2026年9月22日

Evidence for the emergence of stellar magnetic fields during rapid mass transfer

Gregg A. Wade, Tomer Shenar, Pablo Marchant, Michael Abdul-Masih, Matteo Cantiello, Jason Grunhut, Oleg Kochukhov, Hugues Sana et al.

Binary interaction fundamentally alters the evolution of massive stars, yet the physical consequences of mass transfer remain poorly constrained. Here we present high-resolution spectroscopic observations of Plaskett's Star (HD 47129) that reveal small radial-velocity variations of its magnetic secondary, coherent with the system's 14.4 d orbital period. These measurements support an evolved, post-mass-transfer configuration in which the narrow-lined primary is a partially Roche-lobe-filling str…

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astro-ph.EPnlin.CD2026年9月22日

Large-scale chaos in restricted hierarchical triples driven by short-range forces

Xiaoyan Leng, Hanlun Lei

Context: The eccentric von Zeipel-Lidov-Kozai effect, which is widely applied to diverse astrophysical settings, can drive the inner binary to extremely high eccentricities, where short-range forces such as general relativity (GR) become prominent. Aims: Poincare surfaces of section show that GR effects reshape phase-space structures, giving rise to a widespread and large-scale chaotic sea. This work aims to uncover the underlying mechanism of GR-enabled chaos. Methods: The dynamical structures…

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astro-ph.EPastro-ph.GAastro-ph.IM2026年9月22日

1I/'Oumuamua-like objects's SFDs with older, current and future surveys

Rodrigo Albornoz-Montenegro, César Fuentes

Interstellar Objects (ISOs) may provide direct evidence of planetesimals ejected from early-stage solar systems. Studying these objects and predicting their detection through various surveys is vital for enhancing our understanding of planetary formation. We show how ISO size distribution (SFD), f_D~D^-q, controls expected detections in current and future surveys. We focus on TESS and the Vera Rubin Observatory LSST while analyzing Pan-STARRS and ATLAS. TESS is expected to detect ~1 ISO from sha…

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