Related papers: Generalized compactness limit from an arbitrary vi…
Gamma-ray bursts (GRBs) are fascinating sources studied in modern astronomy. They are extremely luminous electromagnetic explosions in the Universe observed from cosmological distances. These unique characteristics provide a marvellous…
The initial Lorentz factor ($\Gamma_{\text{0}}$) plays a crucial role in uncovering the physical characteristics of gamma-ray bursts (GRBs). Previous studies have indicated that the ambient medium density index $k$ for GRBs falls in the…
If gamma ray bursts are highly collimated, radiating into only a small fraction of the sky, the energy requirements of each event may be reduced by several (up to 4 - 6) orders of magnitude, and the event rate increased correspondingly. The…
In the framework of the hypothesis on potential sources of some gamma-ray bursts being single compact objects of neutron star type with finite surface temperature in the vicinity of the Sun a method of search in the optical range for a…
Sixty percent of gamma-ray bursts (GRBs) reveal strong MgII absorbing systems, which is a factor of ~2 times the rate seen along lines-of-sight to quasars. The discrepancy in the covering factor is most likely to be the result of either…
Aims. We aim to provide an explanation for the PA rotation in GRBs and find the physical conditions that lead to the rotation by 90 degrees in the toroidal magnetic-field (MF) model. Moreover, we present some observable polarization…
We have performed searches for isolated flares and for steady flickering in Gamma Ray Burst light curves on the microsecond to millisecond time scales. Two bursts out of our sample of 20 revealed four isolated flares with time scales from…
Gamma-ray bursts (GRBs) are cosmologically distributed, very energetic and very transient sources detected in the gamma-ray domain. The identification of their x-ray and optical afterglows allowed so far the redshift measurement of 150…
If gamma-ray bursts have a cosmological origin, the sources are expected to trace the large-scale structure of luminous matter in the universe. I use a new likelihood method that compares the counts-in-cells distribution of gamma-ray bursts…
Intrinsic variability was searched for in arrival times of six gamma-ray bursts (GRBs) at high energies -- between 30 MeV and 2 GeV -- detected by the Fermi satellite's Large Area Telescope (LAT). The GRBs were selected from the Fermi LAT…
Gamma-ray bursts (GRB) are generally believed to be efficient particle accelerators. In the presence of energetic protons in a GRB jet, interactions between these protons and intense radiation field of the GRB are supposed to induce…
We present motivations for and study feasibility of a small, rapid optical to IR response gamma ray burst (GRB) space observatory. By analyzing existing GRB data, we give realistic detection rates for X-ray and optical/IR instruments of…
The origin of prompt emission from gamma ray bursts remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the…
The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar-mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit…
The origin of prompt emission in $\gamma$-ray bursts (GRBs) is highly debated topic. The observed spectra are supposed to play a crucial role in constraining the location of the emitting region, the strength of the magnetic field and the…
In the subclass of high-mass X-ray binaries known as "microquasars", relativistic hadrons in the jets launched by the compact object can interact with cold protons from the star's radiatively driven wind, producing pions that then quickly…
There is strong evidence for the existence of black holes(BHs) in some X-ray binaries and most galatic nuclei, based on different measuremental approaches, but black holes aren't finally identified for the lack of very firm observational…
We present an observational approach for the independent detection of the early optical emission of long gamma-ray bursts (GRBs). For this purpose, we explore the potential of the Large Array Survey Telescope (LAST). This array of small…
We show that the recent measurements of linear polarization in gamma rays from GRB 930131 and GRB 960924 constrain certain types of relativity violations in photons to less than parts in 10^{37}, representing an improvement in sensitivity…
We review five studies of the gamma-ray burst (GRB) luminosity function that are based on one or more of the proposed luminosity criteria, i.e., variability, spectral lag and spectral hardness. A comparison between the resulting luminosity…