高能天体物理现象
Previous VLBI kinematic studies of the blazar 3C 66A have unveiled complex jet kinematic behaviors. Using follow-up high-resolution VLBI observations and archival data, we investigate the morphology and the variations in orientation and…
The standard approach to modeling X-ray spectral data relies on local optimization methods, such as the Levenberg-Marquardt algorithm. While effective for simple models and speedy spectral fitting, these local optimizers are prone to…
Recently, the Pierre Auger Observatory has found strong evidence supporting the extragalactic origin of the most energetic cosmic rays. Despite several observed excesses in the distribution of arrival directions for the highest energy…
We perform the classification of black hole and neutron star X-ray binary systems using deep neural networks applied to archival RXTE X-ray spectral data. We first construct two neural network models: one trained using only spectral flux…
The decay of magnetically dominated turbulence exhibits robust inverse transfer of magnetic energy even in the absence of net magnetic helicity, challenging traditional cascade-based phenomenology. While recent studies suggest that magnetic…
The Fe K$\alpha$ fluorescence line at 6.4 keV is a powerful probe of cold matter surrounding X-ray sources and has been widely used in various astrophysical contexts. The X-ray microcalorimeter spectrometer onboard XRISM can measure line…
(Abridged) Recent JWST observations of Cassiopeia A (Cas A) reveal unprecedented ejecta substructure, including a web of filaments and the enigmatic "Green Monster" (GM), characterized by nearly circular holes and rings. These features…
The Westerlund 1 (Wd 1) is the most massive known young star cluster in the Galaxy, and an extended $\gamma$-ray source HESS J1646-458 surrounding it has been detected up to 80 TeV in the very high energy, implying that cosmic rays (CRs)…
Individual radio pulses from a pulsar are directly linked to the underlying emission processes and the associated magnetic field geometry within its magnetosphere. Thus, single-pulse studies across frequencies can provide crucial insights…
We investigate the thermodynamics of a relativistic Fermi gas governed by a modified dispersion relation in the Magueijo Smolin (MS) formulation of Doubly Special Relativity (DSR), characterized by the presence of an invariant ultraviolet…
We introduce a complete model for dephasing due to line-of-sight acceleration (LOSA) in gravitational wave (GW) signals from stellar-mass binary black holes (BBHs) in three-body systems. Our prescription provides curvature- and…
High-energy blazar light curves, in X-rays and beyond, have historically preferred a log-normal flux distribution, signifying multiplicative processes either in the jet itself or due to connection(s) with accretion. Here we present 18 year…
Tidal disruption events (TDEs) occur when a star crosses the tidal radius of a black hole (BH) and is ripped apart, providing a powerful way to probe dormant BHs over a wide mass range. In this study, we present our late-time observations…
We investigate magnetic-field amplification driven by the nonresonant hybrid (NRH or Bell) instability and its impact on cosmic-ray (CR) acceleration at reverse shocks of ultrafast outflows (UFOs) from active galactic nuclei (AGN). Previous…
The identification and classification of Fermi blazars are core topics in high-energy astrophysics. To enable precise spatial cross-identification, we constructed two high-precision catalogs: the updated 4FGL-Xiang-DR2 (DR2) and a…
Quasiperiodic eruptions (QPEs), the repeated outbursts observed in soft X-ray bands, have attracted broad interest, but their physical origin is under debate. One of the popular models, the star-disk collision model, suggests that QPEs can…
The phase evolution of gravitational waves (GWs) can be modulated by the astrophysical environment surrounding the source, which provides a probe for the origin of individual binary black holes (BBHs) using GWs alone. We here study the…
We present six case studies from a broad mass range ($1 - 10^9$ $M_\odot$) of astrophysical objects, each of which exhibit signs of jets and emit intense high energy gamma rays ($>10$ GeV). Many of these objects also emit spatially…
A search for pulsars was carried out using a Large Phased Array (LPA) radio telescope at a frequency of 110.4 MHz with a time resolution of 3.072 ms and a frequency resolution of 19.5 kHz with a 2.5 MHz bandwidth used. The survey was…
Results from GRBAlpha, VZLUSAT-2 and GRBBeta CubeSats and their on-board gamma-ray detectors for monitoring transients are summarised in this article. GRBAlpha was a 1U CubeSat launched in March 2021 to a 550 km altitude polar orbit…