高能天体物理现象
Ultrahigh-energy gamma rays ($E_{\gamma}>100 \, {\rm TeV}$) have been detected from a handful of astrophysical sources. Due to the Klein-Nishina suppression of inverse Compton scattering at such high energies, it has sometimes been argued…
The recent gravitational-wave (GW) alert from a compact object merger involving at least one subsolar mass (SSM) object has prompted questions about their origins. S251112cm is reported by LIGO/Virgo with a false alarm rate of 1 per 6.2…
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 distant cluster PKS 0745-191 (z = 0.103) with a 54 ks…
The formation channels of binary black hole (BBH) mergers detected by the LIGO/Virgo/KAGRA (LVK) network remain uncertain. While BBH mergers occurring inside active galactic nucleus (AGN) disks may interact with surrounding gas and generate…
The preparation of the next-generation of large-scale radio experiments requires running a large number of simulations to explore multiple detector configurations over vast areas and develop novel methods for the reconstruction of air…
The Sun produces a steady signal of high-energy gamma rays through interactions of Galactic cosmic rays (GCRs) with its atmosphere. Observations with Fermi-LAT and HAWC have revealed a gamma-ray flux significantly higher than early…
We show that there is a strong dependence of the radio LDF electric field amplitudes at ground level on the position of $X_{\rm max}$ in the atmosphere, even accounting for differences in the EM energy of the showers. Since an $X_{\rm max}$…
Long Gamma-Ray Bursts (LGRBs) are often associated with the collapse of stripped-envelope massive stars. Powerful relativistic jets drill through the stellar envelope before the gamma emission. Previous hydrodynamical studies imposed jets…
The source binary of the gravitational-wave (GW) event GW230529, detected at the beginning of the fourth LIGO-Virgo-KAGRA observing run, was inferred to consist of a NS and a compact object in the lower mass gap, a purported gap between the…
Shock-generated transients, such as hot flow anomalies (HFAs), upstream of planetary bow shocks, play a critical role in electron acceleration. Using multi-mission data from NASA's Magnetospheric Multiscale (MMS) and ESA's Cluster missions,…
I show that a newly estimated fraction of normal type Ia supernovae (SNe Ia) that interact within about 100 days of explosion with circumstellar material (CSM), called SNe Ia-CSM, is compatible with a recently estimated fraction of normal…
Recent observations by LHAASO and HAWC have revealed extended ultrahigh-energy (UHE; $E>100$ TeV) gamma-ray emission assoicated to the black-hole X-ray binary (BHXRB) V4641 Sgr, with a spectrum extending up to $\sim0.8$ PeV. Interpreting…
Context: Growing observational evidence suggests that sub-relativistic astrophysical jets may accelerate particles at slowly evolving standing shocks. Recollimation shocks are expected to develop when jets expand in dense environments;…
The quest to identify the true nature of dark matter remains one of the most pressing challenges in modern physics. We present a novel approach to probe the Weakly Interacting Massive Particle (WIMP) paradigm by analyzing density…
Analyses of Imaging Atmospheric Cherenkov Telescope (IACT) data for extended $\gamma$-ray sources face the issue that the field of view does not offer sufficient regions for background estimations. In cases where the source angular size…
Attempts to reveal the spectroscopic diversity of Type Ia supernovae (SNe Ia) have led to subclassification schemes such as the Branch system, which classifies SNe Ia into four categories: core normal (CN), broad line (BL), cool (CL), and…
Binary neutron stars (BNSs) are one of the most important gravitational wave (GW) sources, which provide key insights to evolution of massive binary stars and nuclear physics. Beyond Laser Interferometer Space Antenna (LISA), Taiji, and…
We present a comprehensive analysis of Low Frequency Quasi-periodic Oscillation (LFQPO) associated time-lags in the persistently variable black hole binary GRS 1915+105 using 441 ks of \textit{AstroSat} observations from March 2016 to March…
The Galactic plane survey conducted by the High Energy Stereoscopic System (H.E.S.S.) has revealed numerous teraelectronvolt (TeV) sources, many of which remain unidentified. HESS~J1832$-$085 is a point-like TeV source lacking a confirmed…
PSR J1922+3745 was recently identified as a radio pulsar toward the old open cluster NGC 6791, raising the prospect of the first pulsar associated with an open cluster. We report FAST follow-up observations that yield a phase-coherent…