高能天体物理现象
Blazars are active galactic nuclei known for their extreme variability, offering unique opportunities to study jet physics and high-energy emission mechanisms. In 2024, the Flat Spectrum Radio Quasar (FSRQ) OP313 underwent a remarkable…
Particle acceleration in relativistic shocks of electron-positron plasmas with proton admixture is investigated through two-dimensional (2D) particle-in-cell (PIC) simulations. The upstream plasma, with a bulk Lorentz factor of $10$ and a…
Gamma-ray bursts (GRBs) are cosmic events occurring at large distances beyond our galaxy. They provide a unique opportunity to study electromagnetic patterns not seen elsewhere. When the collimated GRB outflow interacts with the outer…
Interpreting the spectral energy distributions (SEDs) of astrophysical objects with physically motivated models is computationally expensive. These models require solving coupled differential equations in high-dimensional parameter spaces,…
GW200105 is a compact binary coalescence (CBC) event, consisting of a neutron star and a black hole, observed in LIGO-Virgo-KAGRA's (LVK's) third observing run (O3). Recent reanalyses of the event using state-of-the-art waveform models have…
We report on the search for ultra-high-energy neutrinos from the prompt emission of gamma-ray bursts (GRBs) using Surface Detector (SD) data from Phase I of the Pierre Auger Observatory (2004-2021). A total of 570 GRBs occur within the most…
We present a detailed analysis of sub-pulse modulations in nine pulsars which show evidence of changes in sub-pulse drift direction as a function of pulse longitude in the Thousand Pulsar Array single pulse survey with MeerKAT. We confirm…
We revisit the problem of the capture of a primordial black hole (PBH) by a neutron star, accounting for the tidal perturbation from a nearby star or planet. For asteroid-mass PBHs, which could constitute all of the dark matter in the…
The radiation reprocessing model, in which an optically-thick outflow absorbs the high-energy emission from a central source and re-emits in longer wavelengths, has been frequently invoked to explain some optically bright transients, such…
Violent astrophysical events, including core-collapse supernovae and binary neutron star mergers, can result in rotating neutron stars with diverse degrees of differential rotation. Oscillation modes of these neutron stars could be excited…
The enigma of cosmic ray origin and propagation stands as a key question in particle astrophysics. The precise spatial and spectral measurements of diffuse Galactic gamma-ray emission provide new avenues for unraveling this mystery. Based…
CTA~1 is a composite supernova remnant featuring a shell structure and an inner Pulsar Wind Nebula. The shell is visible in the radio band, while Fermi has detected the radio-quiet pulsar PSR J0007+7303 at its core. Gamma-ray detectors such…
CSS100217 is considered a peculiar tidal disruption event (TDE) candidate occurring in an active galactic nucleus (AGN). Unlike typical TDEs, where the post-flare luminosity is equal to that pre-flare, CSS100217 decayed to $\sim$ 0.4…
Galactic $\gamma$-ray sources can be produced by either high-energy protons via proton-proton collisions or electrons/positrons via inverse Compton scattering. Distinguishing between the hadronic and leptonic origin of $\gamma$-ray emission…
We present on results of a spatially resolved spectral analysis of G1.9+0.3, the youngest known supernova remnant in the Galaxy. The X-ray spectra are well described by synchrotron emission from a power-law electron distribution with an…
The recent announcement of the detection of the ultra-high-energy (UHE) neutrino event KM3-230213A by the KM3NeT telescope represents a critical opportunity to explore the origins of cosmic neutrinos and their potential gamma-ray…
In the past decade, Swift has performed several AGN high-cadence reverberation mapping campaigns, and generally found that the UV/optical interband lags are $\sim$3 times longer than predicted for a standard thin disk, thus coined "the…
Gamma-Ray Bursts are among the most powerful and violent events in the Universe. Despite over half a century of observations of these transient sources, many open questions remain about their nature and the physical emission mechanisms at…
We present a comprehensive spectro-temporal analysis of GRS $1915+105$ observed with AstroSat during June, $2017$. A detailed study of the temporal properties reveals the appearance of an `unknown' variability class ($\tau$) during $\rho…
The nature of Type Ia supernova (SN Ia) progenitor systems and the mechanisms that lead up to their explosions are still widely debated. In rare cases the SN ejecta interact with circumstellar material (CSM) that was ejected from the…