研究動向

astro-ph.HE2026年8月16日

The detection prospects of the polarizations in the plateau phase of GRB afterglow by eXTP

Shu-Ting Wu, Mi-Xiang Lan, Zelin Ren, Ming-Yu Ge, Xue-Feng Wu, Zi-Gao Dai

Approximately (20-50)$\%$ of the gamma-ray burst (GRB) X-ray afterglows exhibit the shallow decay features. Two popular energy-injection models had been proposed to interpret such observational phenomenons, the relativistic wind bubble (RWB) model with a Poynting-flux injection and the structured ejecta (SE) model with a dynamical energy injection. Polarization predictions of the two models had been investigated and can be used as a test of the two models. However, the impacts of the parameters…

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astro-ph.IM2026年8月16日

Wide field Slitless Spectroscopy with JWST's MIRI

Andreea Petric, Sarah Kendrew, David Law, Alberto Noriega Crespo, Bryan Holler, Jane Morrison, Jonathan Aguilar, Misty Cracraft et al.

We present a snapshot of the ongoing efforts to obtain background-subtracted, wavelength-, and flux-calibrated spectra taken with the new Wide-Field Slitless Spectroscopy (WFSS) mode for the MIRI instrument on the James Webb Space Telescope (JWST), offered for the first time in JWST Cycle 5 (starting July 2026). We describe here the capabilities of the new mode, the operational concept, and an overview of the calibration and pipeline development activities that are currently ongoing.

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astro-ph.SRphysics.data-an2026年8月16日

Determining low-$\ell$ p-mode frequency shifts in Sun-like stars: Enhancing the cross-correlation technique with filters

Samarth G. Kashyap, Laurent Gizon, Jesper Schou, Rachel Howe

Acoustic mode frequencies in the Sun and Sun-like stars change due to magnetic activity, on time-scales much larger than the star's rotation and much smaller than its evolution. Given the poor S/N of the observed stellar p-modes, it is challenging to measure the changes of individual mode frequencies. Typically, power spectra of different time series segments are cross-correlated to estimate a mean p-mode frequency change, which ends up averaging over the individual mode contributions. We seek t…

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astro-ph.GA2026年8月16日

Improved constraints on the Milky Way potential using the M68 stream and DESI spectroscopic data

Carles G. Palau, Wenting Wang, Jiaxin Han, J. Aguilar, S. Ahlen, F. Beutler, D. Bianchi, D. Brooks et al.

We present a selection of stars belonging to the stellar stream of the M68 (NGC 4590) globular cluster, also known as Fjörm. This star selection is an improvement on previous ones that used only Gaia data, as it incorporates spectroscopic measurements from the DESI survey and photometric data from the DESI Legacy Surveys. The selection contains 96 stars, each with five phase-space parameters from Gaia-DR3 and radial velocity from DESI, covering the entire observed section of the stream. This con…

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astro-ph.SR2026年8月16日

Stability of circumbinary orbits in misaligned triple star systems

Stephen Lepp, Rebecca G. Martin

We investigate the stability of circumbinary orbits in hierarchical triple star systems, focusing on the effects of a misaligned outer companion star. Test particles are subject to competing gravitational torques from the inner binary and the outer binary companion. With secular theory we estimate the outer radius of particle stability, where the torques balance. We find good agreement with $n$-body simulations across a wide range of triple star configurations. Stable circumbinary orbits can exi…

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hep-exastro-ph.EPhep-phphysics.geo-ph2026年8月15日

Deep Earth imaging through neutrino and seismic tomography

Sanjib Kumar Agarwalla, Arjun Datta, Amol Dighe, Vinod Kumar Gaur, Anuj Kumar Upadhyay

This article is a report on the Deep Earth Neutrino + Seismic Imaging and TomographY (DENSITY 2026) mini-workshop, held on 23--24 February 2026 in the Department of Earth and Climate Science at the Indian Institute of Science Education and Research (IISER), Pune. The workshop was jointly organised by IISER Pune and the Institute of Physics (IOP), Bhubaneswar. Researchers from Earth Sciences and Neutrino Physics participated in the workshop to explore multipronged approaches for studying the deep…

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astro-ph.SRphysics.plasm-ph2026年8月15日

A self-consistent solar coronal heating model by Alfvenic waves

Hidetaka Kuniyoshi, Richard J. Morton

Alfvenic waves are prevalent throughout the solar atmosphere and are believed to play an essential role in coronal heating, classified as alternating current (AC) heating in contrast to direct current (DC) heating associated with quasi-static magnetic field line braiding. The relative importance of AC versus DC heating depends on the details of the photospheric driver and on the configuration of the magnetic field. Moreover, even if AC heating prevails, several wave dissipation mechanisms have b…

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astro-ph.IM2026年8月15日

Design and Realization of the LST Main Structure for the Cherenkov Telescope Array

T. Schweizer, J. Eder, H. Wetteskind, C. Jablonski, R. Stadler, R. Mirzoyan, D. Paneque, T. Masahiro et al.

The 23 m diameter Large Size Cherenkov Telescope (LST) for CTA, located at 2250 m a.s.l. on the Canary Island of La Palma, is the next-generation Cherenkov telescope following MAGIC, H.E.S.S., and VERITAS. To enable rapid repositioning (180° in 18 s) for gamma-ray burst observations, the mechanical structure was designed to be ultra- lightweight (110 tons). The space-frame structure consists of slender struts made of carbon fibre, aluminium (dish and camera mast), and steel. The telescope is des…

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astro-ph.IM2026年8月15日

Adapting the 23m LST-North mechanical structure design for the strong Chile seismic environment

Thomas Schweizer, Josef Eder, Teshima Masahiro, Holger Wetteskind, Razmik Mirzoyan

The 23-meter-diameter Large-Sized Telescope (LST) is the largest size telescope of the next generation Cherenkov Telescope Array (CTA). The first telescope, LST-1, was installed at the Roque de los Muchachos Observatory (ORM) on La Palma at an altitude of 2,250 m in 2018 and has been in operation since 2019. Its ultra-lightweight structure (110 tons) enables extremely rapid repositioning (180° in 18 seconds) and has been designed to withstand extreme environmental conditions, including storms an…

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astro-ph.IMgr-qc2026年8月15日

Stress-Testing DANTE under Detector Domain Shift: a Representation-Coherent Reanalysis of LIGO O4a

Luca Cirfeta

This sixth version of the Domain-Adaptive Network for Transient Evaluation (DANTE) preprint stress-tests an unsupervised transient-noise pipeline under representation mismatch and observing-run adaptation. We reanalyse 10,429 detector-time strain candidates from 42 LIGO O4a sessions using frozen DINOv2 patch embeddings and a Top-k multiple-instance score. Candidate and native-background Q-transforms share Q in [4,64], and detector-specific thresholds are calibrated from 5,000 run-native windows…

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astro-ph.IMgr-qc2026年8月15日

Stress-Testing DANTE under Detector Domain Shift: a Representation-Coherent Reanalysis of LIGO O4a

Luca Cirfeta

This sixth version of the Domain-Adaptive Network for Transient Evaluation (DANTE) preprint stress-tests an unsupervised transient-noise pipeline under representation mismatch and observing-run adaptation. We reanalyse 10,429 detector-time strain candidates from 42 LIGO O4a sessions using frozen DINOv2 patch embeddings and a Top-k multiple-instance score. Candidate and native-background Q-transforms share Q in [4,64], and detector-specific thresholds are calibrated from 5,000 run-native windows…

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astro-ph.IMastro-ph.EPmath-phmath.DS2026年8月15日

Parameter estimation in differential equations: Mathematical foundation for satellite gravimetry, review and perspectives

Peiliang Xu

Satellite gravimetry has become essential in many areas of earth science. However, the resolution of satellite gravitational models remains low at scales of a few hundreds km and no gravity recovery methods can take full advantages of unprecedented high accuracy of satellite tracking measurements. We first provide a unified theoretical framework of parameter estimation in differential equations for satellite gravimetry and then briefly review the mathematical methods to compute the gravity field…

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astro-ph.EPastro-ph.IM2026年8月15日

Scaling of microcraters with molten rims derived from laser-induced cratering experiments

S. Sato, H. Shibayama, K. Nagai, H. Katsuragi

Microcraters with molten rims are widely observed in returned samples from the Moon and asteroids. These features reflect the conditions of small-scale impact events, but the impact velocities required for their formation are not well understood. In this study, we use well-controlled laser irradiation on rock surfaces as an experimental analog to investigate the formation of these molten-rim craters. Specifically, we derive a scaling relation between crater volume, total irradiation energy, and…

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astro-ph.SRastro-ph.HE2026年8月15日

Panchromatic JWST Observations and Models of the Dim Type Iax Supernova 2024vjm at 200 days

E Baron, J. M. DerKacy, C. Ashall, M. Shahbandeh, Peter H. Hauschildt, T. Barman, J. P. Aufdenberg, C. R. Burns et al.

We report JWST spectra and photometry of the underluminous SN Iax 2024vjm obtained 202.8 restframe days post-explosion. The spectrum exhibits a rich set of forbidden lines from low-ionization, intermediate-mass, and iron-group elements, notably the [Ni II] 6.64 micron resonance line, which is a direct indicator of stable nickel. Strong CO and SiO emission is detected alongside a warm dust continuum; the spectral properties are consistent with pre-existing rather than newly formed dust. Synthetic…

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astro-ph.GA2026年8月15日

Aromatics and Aliphatics in Local Star-Forming Galaxies as Probed by AKARI

Junhao Peng, Xuejuan Yang, Aigen Li

Polycyclic aromatic hydrocarbon (PAH) molecules are abundant and widespread in galaxies and their infrared (IR) emission traces star formation. PAH molecules in astronomical environments often have aliphatic contents as revealed by the detection of the 3.4 micron aliphatic C--H stretch, a weak satellite feature accompanying the 3.3 micron aromatic C--H stretch. Here, we selected 102 local star-forming galaxies from the AKARI archive, including 66 galaxies each of which hosts an active galactic n…

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astro-ph.HEastro-ph.GA2026年8月15日

An ALMA view of the Jet-Arc CO clouds toward the TeV $γ$-ray source HESS J1023-575 and Westerlund 2; Evidence for the footprints of microquasar jets, the very powerful cosmic-ray accelerator in the Galactic disk

Yasuo Fukui, Kisetsu Tsuge, Hidetoshi Sano, G. R. Bhuvana, Rin I. Yamada, Ryoji Matsumoto, Yuta Asahina, Tsuyoshi Inoue et al.

The TeV $γ$-ray source HESS J1023-575 (HESSJ 1023 hereafter) is one of the brightest H.E.S.S. sources near the young massive cluster Westerlund 2. HESS J1023 shows a remarkable positional alignment with the Jet and Arc CO clouds on its eastern and western sides over 170 pc length. We have carried out sub-pc scale observations of the CO clouds with ALMA and have discovered that the clouds consist of numerous thin filamentary features of $\sim$0.5 pc width and 10--20 pc length at distance of 7.5 k…

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astro-ph.GAastro-ph.SR2026年8月15日

Detection of Aliphatically Deuterated Aromatic Hydrocarbons in the Large Magellanic Cloud 30 Doradus Star-Forming Complex

Junhao Peng, Xuejuan Yang, Aigen Li

The unidentified infrared (IR) emission (UIE) bands at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 micron are ubiquitously seen in a wide variety of astrophysical environments. While the exact assignment of these UIE bands remains controversial, they are generally ascribed to C--H and C--C stretching and bending vibrations of aromatic hydrocarbon molecules. Here, based on observations made with the Near Infrared Spectrograph (NIRSpec) and the Mid Infrared Instrument (MIRI) aboard the James Webb Space Tele…

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astro-ph.GAphysics.chem-ph2026年8月15日

Infrared Spectroscopy of Cyanonaphthalenes under Interstellar Relevant Conditions and Their Potential Connection with Astronomical Aromatic Infrared Bands

Jiaqi Xin, Jianzhi Xu, Piero Ferrari, Gao-Lei Hou

Context. Aromatic infrared bands (AIBs) are widely observed in diverse astrophysical environments and are generally attributed to vibrational emission from polycyclic aromatic hydrocarbons (PAHs). The recent interstellar detection of 1-cyanonaphthalene (1-CNN) and 2-cyanonaphthalene (2-CNN) has motivated detailed infrared spectroscopic studies of cyano-substituted PAHs. Aims. We aim to characterize the infrared spectra and vibrational modes of neutral 1-CNN and 2-CNN under cold and gas-phase con…

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astro-ph.GAastro-ph.SR2026年8月15日

Local Interstellar Flow Parameters from the First Intersection of IMAP-Lo's Parameter Tubes

Nathan A. Schwadron, Mitchell M. Shen, Fatemeh Rahmanifard, Eberhard Moebius, Hafijul Islam, Jonathan S. Bower, Maciej Bzowski, Eric R. Christian et al.

The Sun's motion through the interstellar medium creates a flow of interstellar neutral (ISN) atoms through the heliosphere. ISN He, due to its high universal abundance and relatively low ionization rate, is the most abundant of the interstellar species near 1 au and ideal for flow parameter determination. The Interstellar Boundary Explorer (IBEX) measurements of ISN He flow parameters (speed, temperature, and direction) yielded a tube in 4D parameter space -- narrow in cross-section but highly…

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astro-ph.HE2026年8月15日

4U 1538-52 in a Heartbeat: Broadband X-ray Spectral Properties from XMM-Newton and NuSTAR

C. M. Diez, S. Dupourqué, A. -L. Doherty, D. Dickson, A. Zainab, S. Martínez-Núñez, J. M. Torrejón, S. Guillot et al.

Galactic high-mass X-ray binaries (HMXBs) are important systems for studying accretion mechanisms onto compact objects and for investigating the complex stellar winds of massive stars. In particular, HMXBs hosting a neutron star allow us to reveal the structure of the accreted material in X-ray pulsars and consequently to investigate how matter behaves under extreme conditions of pressure and density. These are major scientific goals for XRISM and NewAthena. Here we report on the first out-of-ec…

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astro-ph.GA2026年8月15日

VAPOLA - A multiyear, multiband polarization survey of AGNs and Sgr A* at millimeter wavelengths with ALMA II. Spectropolarimetric properties and their evolution from 2017 to 2023

Douglas Carlos, Ciriaco Goddi, Alejandro Mus, Nicola Marchili, Kazi L. J. Rygl, Ezequiel Albentosa-Ruíz, Iván Martí-Vidal, The Event Horizon Telescope Collaboration et al.

We present a systematic analysis of the spectropolarimetric properties of a sample of 39 active galactic nuclei and Sagittarius A* observed with the Atacama Large Millimeter/submillimeter Array during five VLBI campaigns between 2017 and 2023. We characterize the compact cores in total intensity and polarization, focusing on the behavior or the linear polarization fraction (LP), electric vector position angle (EVPA), and Faraday rotation measure (RM) over time and spectral domains. We investigat…

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astro-ph.GA2026年8月15日

High-spectral-resolution Observations of the [S II] Emission-line Doublet in the Filamentary Nebula Surrounding NGC 1275

Benjamin Vigneron, Julie Hlavacek-Larrondo, Carter Lee Rhea, Christoph Pfrommer, Greg L. Bryan, Megan Donahue, Alastair Edge, Andrew Fabian et al.

We analyze new high-spectral resolution SITELLE observations (R = $λ/Δλ$ = 7000) of the filamentary nebula surrounding NGC 1275, central galaxy of the Perseus cluster. We present here analysis of the \sii$\lambda6716$ and \sii$\lambda6731$ emission line doublet, using its ratio to determine the electron density of the optically emitting filaments. We compare these measurements with electron densities derived from deep Chandra X-ray observations of the intra-cluster medium (ICM) to determine if a…

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astro-ph.IM2026年8月15日

Sub-Pixel Calibration of CMOS Sensors for Precision Astrometry

M. Shao, I. Hahn

Many sources of systematic error are important to centroid the position of a star below the level of $10^{-4}$ of the FWHM of the stellar image. One of the more important sources of centroiding error is the imperfect position of the pixels in a focal plane array. In this paper, we discuss the calibration of pixel position of multiple commercial CMOS detectors. Focal plane arrays are semiconductor devices fabricated with 10's nanometer precision. However, the effective location of a pixel can be…

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astro-ph.IM2026年8月15日

Enabling Quantitative Polarimetry for Keck/NIRC2: Preliminary Mueller Matrix Model Calibration

Manxuan Zhang, Briley L. Lewis, Maxwell A. Millar-Blanchaer, Eduardo Marin, Jayke S. Nguyen, William Melby, Carlos Alvarez, Jaren N. Ashcraft et al.

The Keck/NIRC2 infrared imager was upgraded in 2025 with dual-beam polarimetric observing modes spanning approximately 1.1--4.1 microns (JHKL' bands). We present a preliminary JHK calibration of NIRC2 Polarimetry using a wavelength-dependent Mueller matrix model of the Keck tertiary mirror (M3), half-wave plate (HWP), image rotator (IMR), downstream optics, and Wollaston prism. We constrain the model downstream of M3 using dome flat sequences spanning ten HWP and nine IMR angles in each band. Al…

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astro-ph.IM2026年8月15日

An open-source data processing pipeline for Keck / NIRC2-Polarimetry

Briley L. Lewis, Maxwell A. Millar-Blanchaer, Rebecca Zhang, Jayke Nguyen, Max Brodheim, Ashish Uhlmann

The Keck/NIRC2 infrared imager was recently upgraded with a new suite of polarimetric observing modes. This polarimetry upgrade (referred to as NIRC2-Pol) will open up a wide range of new astronomical studies, including investigations of exoplanets, the Galactic center, active galactic nuclei and the solar system. Astronomical polarimeters require sophisticated data reduction, especially for quantitative polarimetry requiring the use of a Mueller Matrix model for instrumental polarization calibr…

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astro-ph.HEphysics.space-ph2026年8月15日

X-ray thread/Nonthermal Radio Filament associations: Evidence for Interstellar Magnetic Reconnection

Q. Daniel Wang

Nonthermal radio filaments (NTFs), first discovered at 20-centimeter wavelength more than four decades ago, are among the most enigmatic structures at the Galactic Center. They still defy a clear explanation. These striking narrow features trace intense magnetic fields and often stand in bold contrast to the Galactic plane. Recent discoveries have revealed surprising associations: some NTFs align well with X-ray threads that seem to exhibit Fe He-$α$ emission. Here, I present preliminary results…

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astro-ph.EP2026年8月15日

The Enceladian crater production function

E. W. Wong, S. C. Werner, M. R. Kirchoff, R. Brasser

Interpreting Enceladus's past and present surface history and interior state remains challenging, owing to uncertain prescription of its impact bombardment history and limited interpretation of its crater statistics. Further progress in understanding its evolutionary history can be achieved with an improved crater chronology model and a thorough assessment of Enceladus's surface. Here we present the first step in the form of a comprehensive, global crater catalogue with geomorphology survey for…

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astro-ph.GAastro-ph.HEastro-ph.SR2026年8月15日

Mixing stochasticity relinquishes evidence for magnetorotational hypernovae

Anmol Aggarwal, Ralph Schoenrich

A recent work claimed by fitting the observed elemental abundance pattern of a halo star with the total yields from single super-/hypernova events that only a magnetorotational hypernova event (a very energetic supernova event that also produces r-process elements) could be the source of the observed abundances. Here, we show that the star's peculiar abundance pattern is better fitted within the framework of mixing stochasticity with yields from a normal core collapse supernova (ccSN; Energy$_{\…

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astro-ph.SR2026年8月15日

JWST/NIRSpec Spectra for Three Ultracool Brown Dwarfs Detected in Extragalactic Surveys: Further Evidence for Phosphine Absorption

Kevin N. Hainline, Samuel A. Beiler, Adam J. Burgasser, Evan S. Chen, Jakob M. Helton, Jarron Leisenring, Brittany E. Miles, Mark S. Marley et al.

We present JWST NIRSpec prism spectra for three ultracool brown dwarfs discovered in extragalactic survey data, two from the JWST Advanced Deep Extragalactic Survey (JADES), and one from Public Release IMaging for Extragalactic Research (PRIMER) survey observed as part of the Mirage or Miracle (MoM) program. The spectra for these sources indicate that one is a T6 dwarf (JADES-GS-BD-11, T$_{\mathrm{eff}} = \sim 700$ K) and two are Y0-Y1 dwarfs (JADES-GS-BD-5, T$_{\mathrm{eff}} = \sim 400$ K, and…

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astro-ph.HEhep-ph2026年8月15日

Unveiling Neutrino Nature with the Diffuse Supernova Background

Marco Manno, Pablo Martínez-Miravé, Irene Tamborra

The true nature of neutrinos--whether Dirac or Majorana--is a foundational, unresolved question. We demonstrate that the diffuse supernova neutrino background (DSNB) offers an untapped avenue to resolve this issue, provided neutrino magnetic moments are $\gtrsim 10^{-14}μ_B$. The intense magnetic fields characteristic of a subset of collapsing massive stars can trigger resonant chirality flips. This flavor conversion physics alters DSNB fluxes in measurable ways that depend on the neutrino natur…

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