Related papers: Redshift Dependent Lag-Luminosity Relation in 565 …
Several pairs of observable properties of Gamma Ray Bursts (GRBs) are known to be correlated. Many such correlations are straightforward predictions of the 'cannonball' model of GRBs. We extend our previous discussions of the subject to a…
We use the BD2 sample of gamma-ray bursts (GRBs) based on 5.9 years of BATSE DISCLA data with a variety of models of the luminosity function to derive characteristic GRB luminosities, space densities and redshift distributions. Previously…
The study of time lags between spikes in Gamma-Ray Bursts light curves in different energy bands as a function of redshift may lead to the detection of effects due to Quantum Gravity. We present an analysis of 15 Gamma-Ray Bursts 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_{GRB}(z), using a method based on Bayesian inference. We find that, despite the qualitative…
Swift/BAT has detected ~ 200 long-duration GRBs, with redshift measurements for ~50 of them. We derive the luminosity function (Phi^{HL}) and the local event rate (rho_0^{HL}) of the conventional high luminosity (HL) GRBs by using the…
We show that the Euclidean value of <V/Vmax> for gamma-ray bursts (GRB) selected on a timescale of 1024 ms is correlated with spectral hardness. The value of <V/Vmax> ranges from 0.42 for soft bursts to 0.26 for the hardest bursts. Given…
We study the effects of the beaming-induced luminosity function on statistics of observed GRBs, assuming the cosmological scenario. We select and divide the BATSE 4B data into 588 long bursts (T$_{90}>2.5$ sec) and 149 short bursts…
We investigate the relationship between soft \xray luminosity and mass for low redshift clusters of galaxies by comparing observed number counts to expectations of $\Lambda$CDM cosmologies. We use a three-parameter model for the conditional…
A strong correlation is reported between gamma-ray burst (GRB) pulse lags and afterglow jet-break times for the set of bursts (seven) with known redshifts, luminosities, pulse lags, and jet-break times. This may be a valuable clue toward…
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…
Long duration Gamma-Ray Bursts (GRBs) have eight luminosity relations where observable burst properties can yield the burst luminosity and hence distance. This turns GRBs into useful tools of cosmology. Recently, two tests have been…
Several correlations among Gamma Ray Burst (GRB) observables with available redshifts have been recently identified. Proper evaluation and calibration of these correlations may facilitate the use of GRBs as standard candles constraining the…
The correlation between the peak spectra energy ($E_p$) and the equivalent isotropic energy ($E_{\rm iso}$) of long gamma-ray bursts (GRBs), the so-called Amati relation, is often used to constrain the high-redshift Hubble diagram. Assuming…
We present a multi-variable regression analysis to several observable quantities for a sample of 15 gamma-ray bursts (GRBs). The observables used in the analysis includes the isotropic gamma-ray energy (E_{gamma,iso}), the peak energy of…
The unrivalled, extreme luminosities of gamma-ray bursts (GRBs) make them the favored beacons for sampling the high redshift Universe. To employ GRBs to study the cosmic terrain -- e.g., star and galaxy formation history -- GRB luminosities…
We compute the probability to detect long Gamma Ray Bursts (GRBs) at z>5 with Swift, assuming that GRBs form preferentially in low-metallicity environments. The model fits well both the observed BATSE and Swift GRB differential peak flux…
We use model-independent luminosity distances of 186 HII galaxy observations to address the circularity problem in the Amati relation for Gamma-ray Bursts (GRBs). For this purpose, we used Artificial Neural Network based interpolation to…
The well-known correlation between the radio luminosity ($L_R$) and the X-ray luminosity ($L_X$) $L_R / L_X \simeq 10^{-5}$ holds for a variety of objects like active galactic nuclei, galactic black holes, solar flares and cool stars. Here…
For over two decades, gamma-ray burst (GRB) prompt emission spectra were modelled with smoothly-broken power laws (Band function), and a positive and tight correlation between the spectral rest-frame peak energy $E_p$ and the total…
Due to their cosmological distances high-energy astrophysical sources allow for unprecedented tests of fundamental physics. Gamma-ray bursts (GRBs) comprise among the most sensitive laboratories for exploring the violation of the central…