Related papers: Absolute Rate, Evolving Luminosity function, and E…
Gamma-ray bursts (GRBs) offer a route to characterizing star-forming galaxies and quantifying high-$z$ star formation that is distinct from the approach of traditional galaxy surveys: GRB selection is independent of dust and probes even the…
The observed redshifts and magnitudes of the host galaxies of gamma-ray bursts (GRBs) are compared with the predictions of three basic GRB models, in which the comoving rate density of GRBs is (1) proportional to the cosmic star formation…
We use the lag-luminosity relation to calculate self-consistently the redshifts, apparent peak bolometric luminosities L_B, and isotropic energies E_iso for a large sample of BATSE gamma-ray bursts. We consider two different forms of the…
Gamma-ray bursts (GRBs) are extremely powerful explosions that have been traditionally classified into two categories: long bursts (LGRBs) with an observed duration T90 > 2 s, and short bursts (SGRBs) with an observed duration T90 < 2 s,…
The empirical classification of Gamma-Ray Bursts (GRBs) is based on their distribution in the plane of burst duration and spectral hardness. Two distinct distributions, long-soft and short-hard bursts, are observed in this plane, forming…
We consider all bursts with known redshift and $\nu F_\nu$ peak energy, $E^{obs}_{peak}$. For a good fraction of them an estimate of the jet opening angle is available from the achromatic break of their afterglow light curve. This allows…
The observational diversity of ``gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic…
In Budai et al. (2020) we argued that angular non-stationarities of gamma-ray burst (GRB) jets can result in a statistical connection between the angle values deduced from jet break times and the variabilities of prompt light curves. The…
The role of relativistic jets in unbinding the stellar envelope during a supernova (SN) associated with a gamma-ray burst (GRB) is unclear. To study that, we explore observational signatures of stellar explosions that are driven by jets. We…
The evolution of the comoving cosmic merger-rate density of neutron star binaries n_c(z) is calculated using a distribution of their merging times provided by population-synthesis computations of binary stars. We adopt an exponential law…
The exact relationship between the long gamma-ray burst (LGRB) rate and the cosmic star formation rate (CSFR) is essential for using LGRBs as cosmological probes. In this work, we collect a large sample composed of 371 Swift LGRBs with…
We exploit the 14 gamma-ray bursts (GRBs) with known redshifts $z$ and the 7 GRBs for which there are constraints on $z$ to determine the GRB rate $R_{\rm GRB}(z)$, using a method based on Bayesian inference. We find that, despite the…
Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift $ < z >$ of the GRBs. In this paper we investigate the effect of evolving lenses on the $< z >$ of GRBs…
The long-term evolution of relativistic jets in gamma-ray bursts (GRBs), particularly from days to months post-burst, remains a fundamental puzzle in astrophysics. Here, we report our very long baseline interferometry observation of the…
It has been suggested that Gamma Ray Bursts (GRB) may enable the expansion rate of our Universe to be measured out to very high redshifts ($z \gsim 5$) just as type Ia supernovae have done at $z \sim$1--1.5. We explore this possibility…
Jet luminosity from active galaxies and the rate of star formation have recently been found to be uncorrelated observationally. We show how to understand this in the context of a model in which powerful AGN jets enhance star formation for…
We consider the time-dependent evolution of a relativistic jet following its breakout through the surface of a massive compact star, as envisaged in the collapsar model of gamma-ray bursts. At breakout, the jet is tightly collimated by the…
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…
As starburst galaxies show a star formation rate up to several hundred times larger than the one in a typical galaxy, the expected supernova rate is higher than average. This in turn implies a high rate of long gamma ray bursts (GRBs),…
We describe a model of the short gamma-ray burst (SGRB) population under a `quasi-universal jet' scenario in which jets can differ in their on-axis peak prompt emission luminosity $L_c$, but share a universal angular luminosity profile…