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astro-ph.HE2026

Revisiting EBL Constraints from Gamma-Ray Observations: A Critical Assessment and Methodological Improvements

K. Abe, S. Abe, J. Abhir +185

The extragalactic background light (EBL), ranging from the infrared to the ultraviolet bands, is the second most intense photon field in the universe, surpassed only by the cosmic…

astro-ph.HE2026

Observations of ionized carbon towards the -ray-bright supernova remnant RX J1713.7-3946

A. R. Thakur, G. P. Rowell, R. Higgins +7

The origin of Galactic Cosmic Rays (CRs), particularly at sub-GeV energies, remains uncertain due to their difficulty in being traced. One possible tracer of low-energy CRs is ioni…

astro-ph.HE2026

Constraints on the VHE counterpart of two binary black hole mergers observed by the MAGIC and CTAO LST-1 telescopes

K. Abe, S. Abe, J. Abhir +358

We present very-high-energy gamma-ray observations of two binary black hole merger candidates, GW240615_113620 and GW241125_010116, performed with the Major Atmospheric Gamma Imagi…

astro-ph.HE2026

Exploring the nature of Galactic unassociated sources detected by the Fermi-LAT

F. Acero, A. Acharyya, A. Adelfio +120

We investigate the nature of the unassociated sources detected by the Fermi-LAT close (|b|<10°) to the Galactic plane, representing 16% of all sources in the 4FGL-DR4 catalog. The…

astro-ph.HE2026

Discovery of CO Clouds Associated with the X-ray Jets of SS 433: Evidence for Shock-Cloud Interaction Enhancing Nonthermal X-ray Emission

Haruka Sakemi, Hidetoshi Sano, Yasuo Fukui +7

We report the first identification of molecular clumps directly associated with the re-brightening regions of the large-scale X-ray jets of SS 433, based on CO ( = 1--0)…

astro-ph.HE2026★ 2 cited

Gamma-ray signature of superluminous supernovae: Fermi-LAT GeV detection of SN 2017egm and evidence of a central engine

F. Acero, A. Acharyya, A. Adelfio +116

Superluminous supernovae (SLSNe) are a rare class of transients with peak luminosities 10-100 times greater than those of standard core-collapse supernovae (SNe). The mechanisms po…

astro-ph.HE2026

Discovery of Molecular and Atomic Gas associated with HESS J1646-458 (Westerlund 1): Spatial TeV Gamma-Ray and Interstellar Proton Correspondence

H. Sano, Y. Fukui, S. Fujimori +21

We report CO and HI studies of molecular and atomic gas toward the TeV gamma-ray source HESS J1646458, widely considered to be associated with the young massive cluster Westerlu…

astro-ph.HE2026

The line modulations of H-like Fe, Ca, Ar, and S observed with /Resolve in Cyg X-3

Tomohiro Hakamata, Hirokazu Odaka, Ryota Tomaru +13

Cygnus X-3, hosting a Wolf-Rayet (WR) star whose dense wind produces various spectral lines due to photoionization by X-rays from a compact object, provides an ideal laboratory for…

astro-ph.HE2026★ 6 cited

XRISM High-Resolution X-ray Spectroscopy of Cygnus X-1 -- highly ionized Iron absorption structures

Shinya Yamada, Natalie Hell, Elisa Costantini +18

We present the first high-resolution X-ray spectral analysis of Cygnus X-1 using XRISM. The observation was carried out from April 7 to 10, 2024, covering the orbital phase range 0…

astro-ph.HE2026

Chasing Gamma-Ray Signals from Binary Neutron Star Coalescences with the Cherenkov Telescope Array: Prospects and Observing Strategies

S. Abe, J. Abhir, A. Abhishek +457

The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo (GW170817), together with its electromagnetic counterpart, th…

astro-ph.HE2026★ 1 cited

Accurate Determination of Chemical Abundances near a Supermassive Black Hole

The XRISM collaboration

The metal abundances in galactic nuclei carry key information on the history of star formation and mass transfer in central regions of galaxies. X-ray fluorescence analysis is a un…

astro-ph.HE2026

Resonant scattering at the center of the galaxy cluster PKS 0745-191 with XRISM

Keita Tanaka, Megan Eckart, Kotaro Fukushima +11

We report evidence for the resonant scattering effect at the center of the galaxy cluster PKS 0745-191 with XRISM. We analyzed XRISM/Resolve commissioning-phase observations of the…

astro-ph.HE2026★ 2 cited

High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System Carinae - Iron K Band Profile Revealed with XRISM

XRISM Collaboration, Marc Audard, Hisamitsu Awaki +138

The supermassive binary system, Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) contin…

astro-ph.HE2026

Monitoring the upper atmospheric temperature and interplanetary magnetic field with the GRAPES-3 muon telescope

S. Paul, K. P. Arunbabu, M. Chakraborty +17

We study the influence of variations in the upper atmospheric temperature and interplanetary magnetic field on the cosmic ray induced atmospheric muon flux measured by the GRAPES-3…

astro-ph.HE2026

The Supernova Remnant G284.31.8 and Its Relation to the Gamma-ray Binary 1FGL J1018.65856

Natsuki Terano, Takaaki Tanaka, Hiromasa Suzuki +6

G284.31.8 is a supernova remnant with a radio shell and thermal X-ray emission. Located near its center is the gamma-ray binary 1FGL J1018.65856, although the physical associ…

astro-ph.HE2026★ 2 cited

First detection of VHE gamma-ray signal from the FSRQ TON 0599

MAGIC Collaboration, K. Abe, S. Abe +245

TON\,0599 (z=0.7247) belongs to the few flat spectrum radio quasars (FSRQs) detected in the very high energy (VHE, \,GeV) gamma-ray band. Its redshift makes it currently o…

astro-ph.HE2025★ 5 cited

Chlorine and Potassium Enrichment in the Cassiopeia A Supernova Remnant

XRISM collaboration

The elements in the universe are synthesized primarily in stars and supernovae, where nuclear fusion favors the production of even-Z elements. In contrast, odd-Z elements are less…

astro-ph.HE2025★ 1 cited

Search for Diffuse Supernova Neutrino Background with 956.2 days of Super-Kamiokande Gadolinium Dataset

K. Abe, S. Abe, Y. Asaoka +245

We report the search result for the Diffuse Supernova Neutrino Background (DSNB) in neutrino energies beyond 9.3~MeV in the gadolinium-loaded Super-Kamiokande (SK) detector with $2…

astro-ph.HE2025★ 2 cited

VHE -ray observations of bright BL Lacs with the Large-Sized Telescope prototype (LST-1) of the CTAO

The CTAO-LST Project, :, K. Abe +331

Cherenkov Telescope Array Observatory (CTAO) is the next-generation ground-based gamma-ray observatory operating in the energy range from 20 GeV up to 300 TeV, with two sites in La…

astro-ph.HE2025★ 4 cited

Road map for the tuning of hadronic interaction models with accelerator-based and astroparticle data

Johannes Albrecht, Julia Becker Tjus, Noah Behling +52

In high-energy and astroparticle physics, event generators play an essential role, even in the simplest data analyses. As analysis techniques become more sophisticated, e.g. based…

astro-ph.HE2025★ 10 cited

Stratified wind from a super-Eddington X-ray binary is slower than expected

XRISM collaboration, Marc Audard, Hisamitsu Awaki +132

Accretion discs in strong gravity ubiquitously produce winds, seen as blueshifted absorption lines in the X-ray band of both stellar mass X-ray binaries (black holes and neutron st…

astro-ph.HE2025★ 12 cited

Delving into the depths of NGC 3783 with XRISM II. Cross-calibration of X-ray instruments used in the large, multi-mission observational campaign

XRISM collaboration

Accurate X-ray spectroscopic measurements are fundamental for deriving basic physical parameters of the most abundant baryon components in the Universe. The plethora of X-ray obser…

astro-ph.HE2025★ 5 cited

Combined dark matter search towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS

LAT Collaboration, S. Abdollahi, L. Baldini +586

Dwarf spheroidal galaxies (dSphs) are excellent targets for indirect dark matter (DM) searches using gamma-ray telescopes because they are thought to have high DM content and a low…

astro-ph.HE2025

Constraining the TeV gamma-ray emission of SN 2024bch, a possible type IIn-L from a red supergiant progenitor. Multiwavelength observations and analysis of the progenitor

The CTAO-LST Project, :, K. Abe +332

We present very high-energy optical photometry and spectroscopic observations of SN 2024bch in the nearby galaxy NGC 3206 (\sim 20 Mpc). We used gamma-ray observations performed wi…