{
  "bibcode": "2021GCN.31291....1F",
  "body": "C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team:\n\nSwift-BAT detected GRB 211221A at 20:48:40 UT (GCN 31273). There was no\nFermi-GBM onboard trigger around the event.\n\nAn automated, blind search for short gamma-ray bursts below the onboard\ntriggering threshold in Fermi-GBM identified no counterparts.\n\nThe GBM targeted search [1], the most sensitive, coherent search for\nGRB-like signals identified a transient most significantly on the 8.192 s\ntimescale, with a location consistent with the Swift-BAT event and\na S/N of 21, using the standard search protocol.\nThe GBM targeted search event was found with the highest\nsignificance with a \"normal\" spectrum (Band function with\nEpeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB.\n\n[1] Goldstein et al. 2019 arXiv:1903.12597",
  "circularId": 31291,
  "createdOn": 1640271900000,
  "email": "cfletcher@usra.edu",
  "subject": "Fermi GBM Sub-Threshold Detection of GRB 211221A",
  "submitter": "Cori Fletcher at USRA  <cfletcher@usra.edu>",
  "eventId": "GRB 211221A"
}