Evidence of extended emission in GRB 181123B and other high-redshift short GRBs. (arXiv:2103.02558v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Dichiara_S/0/1/0/all/0/1">S. Dichiara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Troja_E/0/1/0/all/0/1">E. Troja</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beniamini_P/0/1/0/all/0/1">P. Beniamini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+OConnor_B/0/1/0/all/0/1">B. O'Connor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moss_M/0/1/0/all/0/1">M. Moss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lien_A/0/1/0/all/0/1">A.Y. Lien</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ricci_R/0/1/0/all/0/1">R. Ricci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amati_L/0/1/0/all/0/1">L. Amati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryan_G/0/1/0/all/0/1">G. Ryan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sakamoto_T/0/1/0/all/0/1">T. Sakamoto</a>
We study the high-energy properties of GRB 181123B, a short gamma-ray burst
(sGRB) at redshift $zapprox$1.75. We show that, despite its nominal short
duration with $T_{90}<$2 s, this burst displays evidence of a temporally
extended emission (EE) at high energies and that the same trend is observed in
the majority of sGRBs at $zgtrsim$1. We discuss the impact of instrumental
selection effects on the GRB classification, stressing that the measured
$T_{90}$ is not an unambiguous indicator of the burst physical origin. By
examining their environment (e.g. stellar mass, star formation, offset
distribution), we find that these high-$z$ sGRBs share many properties of long
GRBs at a similar distance and are consistent with a short-lived progenitor
system. If produced by compact binary mergers, these sGRBs with EE may be
easier to localize at large distances and herald a larger population of sGRBs
in the early universe.
We study the high-energy properties of GRB 181123B, a short gamma-ray burst
(sGRB) at redshift $zapprox$1.75. We show that, despite its nominal short
duration with $T_{90}<$2 s, this burst displays evidence of a temporally
extended emission (EE) at high energies and that the same trend is observed in
the majority of sGRBs at $zgtrsim$1. We discuss the impact of instrumental
selection effects on the GRB classification, stressing that the measured
$T_{90}$ is not an unambiguous indicator of the burst physical origin. By
examining their environment (e.g. stellar mass, star formation, offset
distribution), we find that these high-$z$ sGRBs share many properties of long
GRBs at a similar distance and are consistent with a short-lived progenitor
system. If produced by compact binary mergers, these sGRBs with EE may be
easier to localize at large distances and herald a larger population of sGRBs
in the early universe.
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