Fermi GBM Sub-Threshold Detection of GRB 211221A
Abstract
Swift-BAT detected GRB 211221A at 20:48:40 UT (GCN 31273). There was no Fermi-GBM onboard trigger around the event. An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no counterparts. The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals identified a transient most significantly on the 8.192 s timescale, with a location consistent with the Swift-BAT event and a S/N of 21, using the standard search protocol. The GBM targeted search event was found with the highest significance with a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB. [1] Goldstein et al. 2019 arXiv:1903.12597
- Publication:
-
GRB Coordinates Network
- Pub Date:
- December 2021
- Bibcode:
- 2021GCN.31291....1F