Speaker
Description
The sky distribution of Gamma-Ray Bursts (GRBs) has been intensively studied for more than two decades. Most of these studies, test the isotropy of GRBs based on the sky number density distribution. We propose a new method which inspects the isotropy of the properties of GRBs such as their duration, fluences and peak fluxes at various energy bands and different time scales. The method was applied on the Fermi / Gamma-ray Burst Monitor data. We found a relatively significant feature near the Galactic coordinates approximately l = 30 deg, b = 15 deg and radius r = 20 - 40 deg with the inferred probability for the occurrence of such signal (in a random isotropic sample) to be less than a percent. However, more comprehensive analysis using different statistical tests and different samples show that the detected feature can be due to statistical fluctuations. Investigations on the updated Fermi / GBM sample as well as on the data sets of other instruments can clarify on the issue.
