Properties of low-luminosity afterglow GRBs

Abstract

The Low Luminosity Afterglow (LLA) gamma-ray bursts (GRBs) are characterized by their very intrinsically faint X-ray afterglows. They represent 12% of all long (of duration more than 2 s) GRBs (lGRBs) with a measured redshift. They are on average closer than normal lGRBs and their distribution is not affected by the gas and dust from the Milky Way and host galaxies. Additionally, the angle of observation is aligned with the jet's direction, has proven by founding the jet breaks in some cases. In this work, we studied the host galaxy properties (mass, metallicity, star formation rate) of LLA GRBs. These properties were compared to those of normal lGRBs and we found that they are similar. We also showed that the prompt properties of LLA GRBs are somewhat different from that of other lGRBs, as shown by their position in the Amati relation. We computed the volume density of LLA GRBs and found that they have higher rate density compare to normal lGRBs. Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.