A study of the prompt and afterglow emission of the Short GRB 061201

TL;DR

This study analyzes the prompt and afterglow emissions of short GRB 061201, providing insights into its properties, possible jet structure, and host galaxy environment despite the lack of a secure redshift measurement.

Contribution

It offers a detailed multiwavelength analysis of GRB 061201, exploring its jet characteristics and host galaxy associations, which advances understanding of short GRB properties.

Findings

X-ray afterglow shows a temporal break consistent with a jet origin.

No host galaxy detected down to R~26 mag, redshift remains uncertain.

Estimated jet opening angle of 1-2 degrees.

Abstract

Our knowledge of the intrinsic properties of short duration Gamma-Ray Bursts has relied, so far, only upon a few cases for which the estimate of the distance and an extended, multiwavelength monitoring of the afterglow have been obtained. We carried out multiwavelength observations of the short GRB 061201 aimed at estimating its distance and studying its properties. We performed a spectral and timing analysis of the prompt and afterglow emission and discuss the results in the context of the standard fireball model. A clear temporal break was observed in the X-ray light curve about 40 minutes after the burst trigger. We find that the spectral and timing behaviour of the X-ray afterglow is consistent with a jet origin of the observed break, although the optical data can not definitively confirm this and other scenarios are possible. No underlying host galaxy down to R~26 mag was found after fading of the optical afterglow. Thus, no secure redshift could be measured for this burst. The nearest galaxy is at z=0.111 and shows evidence of star formation activity. We discuss the association of GRB 061201 with this galaxy and with the ACO S 995 galaxy cluster, from which the source is at an angular distance of 17'' and 8.5', respectively. We also test the association with a possible undetected, positionally consistent galaxy at z~1. In all these cases, in the jet interpretation, we find a jet opening angle of 1-2 degrees.