Investigating high redshift short GRBs: signatures of collapsars?

Abstract

The conventional classification of Gamma-Ray Bursts (GRBs) as short or long bursts based on their duration is widely accepted as arising from different progenitor sources identified as compact object mergers and collapsars, respectively. However, recent observational shreds of evidence challenged this view, with signatures of collapsars in short GRBs and mergers in long GRBs. We conduct a comparative analysis of the characteristics of short and long GRBs, both at low and high redshifts, taking into account the locations and environments of their host galaxies. Our analysis suggests that some short GRBs at higher redshifts exhibit features similar to long GRBs, indicating a possible collapsar origin. Further investigation, utilizing multi-messenger observations, could provide a resolution to this issue.

Accepted for publication in the Bulletin de la Société Royale des Sciences de Liège as proceeding of the 3rd Belgo-Indian Network for Astronomy and Astrophysics (BINA) workshop, held in Bhimtal, Uttarakhand (India) on 22-24 March 2023