高能天体物理现象
Force-Free Electrodynamics (FFE) describes the evolution of the electromagnetic field in magnetically dominated plasmas, but ceases to be hyperbolic once the magnetic dominance condition $F^{ab}F_{ab}>0$ is lost. We demonstrate that, after…
The 21-cm absorption line of neutral hydrogen has been a long hypothesized observational feature of the spectra of Fast Radio Bursts (FRBs). The difficulties associated with detector noise in extracting HI absorption have been previously…
Pair-instability supernovae (PISNe) are among the most luminous transients in the Universe. However, they have never been confidently observed. Solving this puzzle would have key implications for several astrophysical topics, including…
The origin of the most massive gravitational-wave sources remains elusive. We show that gas accretion can be understood as a transport process in mass space, causing compact objects to migrate through a population at rates determined by the…
We examine published JWST observations of the core-collapse supernova (CCSN) remnant SNR 0540-69.3 and identify a point-symmetric morphology in its inner ejecta. Within the framework of the jittering jets explosion mechanism (JJEM), we…
Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, and offer unique laboratories for studying relativistic jets, compact-object formation, particle acceleration, and the high-redshift Universe. The…
The energy deposition of fast electrons in interstellar molecular gas is considered. We use the rotationally resolved cross sections for electron-impact excitation of H$_2$ molecule that were calculated using the adiabatic-nuclei molecular…
A wide variety of Galactic and extragalactic sources are known to emitradiation across the entire electromagnetic spectrum, including both transient and steady-state phenomena. A few hundred of these sources (~300) have been detected even…
Loop-like patterns between spectral parameters are frequently interpreted as evidence of hysteresis in time-dependent astrophysical emission processes. Such patterns have been reported in hardness-intensity diagrams (HID) of accreting…
In a magnetic field with a complex topology, as can be the Galactic magnetic field, cosmic ray transport cannot simply be described by diffusion parallel and perpendicular to magnetic field lines, because the gradients and curvature of the…
This report summarizes potential studies of the Hi-ReX Science Analysis Group for an Ultra-High Angular Resolution X-ray Observatory. Many potential science cases are presented, spanning a range of astrophysical topics from solar system…
The Einstein Probe (EP) has detected several Fast X-ray Transients (FXTs) associated with broad-lined Type Ic supernovae (SNe), including EP240414a and EP250108a. The observations reveal common features among these FXTs, but the…
Gamma-ray-emitting narrow-line Seyfert 1 ($\gamma$-NLSy1) galaxies represent an enigmatic class of active galactic nuclei (AGNs) bridging populations of radio-quiet and radio-loud AGNs. Here we report the multi-wavelength investigation of a…
The origin of high-energy cosmic rays remain one of astrophysics' greatest unsolved mysteries. SKA-Low will be able to measure air showers initiated by cosmic rays with unprecedented precision in the PeV - EeV energy range, covering the…
Recent gravitational-wave (GW) observations have revealed binary black hole (BBH) mergers with both extreme mass ratios and large effective spin parameters ($\chi_{\rm{eff}}$). GW241011 is a notable example that shows these properties.…
Ultraluminous X-ray sources (ULXs) are non-nuclear X-ray emitters exceeding the Eddington luminosity, offering key insights into extreme accretion physics. Their origin is attributed to either sub-Eddington accretion onto intermediate-mass…
We observed the flat-spectrum radio quasar 4C 29.45 in the BVRI optical bands for 39 nights from February 2022 to July 2022 with the T60 telescope at T\"UB\.ITAK National Observatory (TUG) in Turkey. In this study, we aimed to study flux,…
Open clusters are the primary birthplaces of stars in the Milky Way disk, yet their neutron star progeny are rarely found within them, presumably due to supernova-induced kicks that eject them at birth. Here we report the arcsec-level…
The Fe K $\alpha$ fluorescence line at 6.4 keV has long been used to probe the relative geometry between photoionizing X-ray sources and surrounding cold material in a wide range of astrophysical systems. With the advent of the X-ray…
NGC 1275 showed two TeV $\gamma$-ray outbursts between November 2022 and January 2023, as detected by the Large High Altitude Air Shower Observatory (LHAASO). The source was also active in the X-ray and GeV bands during the TeV outburst…