相关论文: Quantifying the Luminosity Evolution in Gamma-ray …
Studies of the cosmic gamma-ray bursts (GRBs) and their host galaxies are now starting to provide interesting or even unique new insights in observational cosmology. Observed GRB host galaxies have a median magnitude R ~ 25 mag, and show a…
We study the evolution of first star (Population III) binaries. Under specific conditions, these stars may produce high redshift gamma-ray bursts (GRBs). We demonstrate that the occurrence rate of GRBs does not depend sensitively on…
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…
There is growing evidence that long and hard gamma-ray bursts (GRBs), discovered at redshifts between 0.4 and 3.4, are related to some type of supernova (SN) explosions. The GRB ejecta are ultra-relativistic, and possibly beamed. There is a…
We study the evolution with redshift of three measures of gamma-ray burst (GRB) duration ($T_{\rm 90}$, $T_{\rm 50}$ and $T_{\rm R45}$) in a fixed rest frame energy band for a sample of 232 Swift/BAT detected GRBs. Binning the data in…
Gamma Ray Bursts (GRB) are among the brightest objects in the Universe and hence can be observed up to a very high redshift. Properly calibrated empirical correlations between intensity and spectral correlations of GRBs can be used to…
After presenting a short history of gamma-ray burst (GRB) studies, we discuss the current constraints on GRB models which follows from astronomical observations. We concentrate on the energetics of the GRBs with known redshifts and the…
We study the properties of star-forming galaxies selected at 610 MHz with the GMRT in a survey covering $\sim$1.86 deg$^2$ down to a noise of $\sim$7.1\,$\mu$Jy / beam. These were identified by combining multiple classification diagnostics:…
We present late-time Hubble Space Telescope imaging of the fields of six Swift GRBs lying at 5.0<z<9.5. Our data includes very deep observations of the field of the most distant spectroscopically confirmed burst, GRB 090423, at z=8.2. Using…
In this article, we explore the possibility of using the properties of gamma ray bursts (GRBs) to probe the physical conditions in the epochs prior to reionization. The redshift distribution of GRBs is modelled using the Press-Schechter…
We investigate the hydrodynamic evolution of Gamma--Ray Burst (GRB) remnants at late times (>> 1 year), by extending the standard fireball model into the nonrelativistic Sedov--Taylor regime. We calculate the associated synchrotron…
The various possibilities for the progenitors of gamma-ray bursts (GRBs) manifest in differing observable properties. Through deep spectroscopic and high-resolution imaging observations of some GRB hosts, I demonstrate that well-localized…
Gamma-ray bursts (GRBs) are tremendous explosions visible across most of the Universe, certainly out to redshifts of z=4.5 and likely out to z~10. Recently, GRBs have been found to have a roughly constant explosive energy as well as to have…
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…
By cross-correlating large samples of galaxy clusters with publicly available radio source catalogs, we construct the volume-averaged radio luminosity function (RLF) in clusters of galaxies, and investigate its dependence on cluster…
Measuring the star formation rate (SFR) at high redshift is crucial for understanding cosmic reionization and galaxy formation. Two common complementary approaches are Lyman-Break-Galaxy (LBG) surveys for large samples and Gamma-Ray-Burst…
We present a detailed determination of the restframe B-band galaxy luminosity function (LF) as a function of redshift and star formation activity from z=0 to z=0.75. The dataset used for this purpose is a combined sample of over 1700…
Long-duration Gamma Ray Bursts (GRBs) are linked to the collapse of massive stars and their hosts are exclusively identified as active, star forming galaxies. Four long GRBs observed at high spectral resolution at redshift 1.5 <z < 4…
GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the…
The recent discoveries of X-ray and optical counterparts for GRBs, and a possible discovery of a host galaxy, implies that a direct measurement of the red-shift of some GRBs host galaxies is eminent. We discuss the implications of such…