{
  "bibcode": "2021GCN.31312....1L",
  "body": "S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),\nH. A. Krimm (NSF), A. Y. Lien (U Tampa),\nC. B. Markwardt (GSFC), K. L. Page (U Leicester),\nD. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),\nT. Sakamoto (AGU), M. Stamatikos (OSU)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-239 to T+963 sec from the recent telemetry\ndownlink, we report further analysis of BAT GRB 211225B (trigger #1090853)\n(Page et al., GCN Circ. 31305).  The BAT ground-calculated position is\nRA, Dec = 258.545, 17.277 deg which is\n   RA(J2000)  =  17h 14m 10.9s\n   Dec(J2000) = +17d 16' 37.2\"\nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 100%.\n\nThe mask-weighted light curve shows a multi-peaked structure that starts\nat ~T-25 s and likely lasts beyond ~T+152 s when the burst went out of the\nBAT\nfield of view. The main peak occurs at ~T+50 s. T90 (15-350 keV)\nestimated from the available data when the burst was inside the BAT field\nof view is 121.54 +- 2.94 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-24.78 to T+139.82 sec is best fit by\na power law with an exponential cutoff.  This fit gives a photon\nindex 1.31 +- 0.14, and Epeak of 139.9 +- 51.5 keV (chi squared 52.29\nfor 56 d.o.f.).  For this model the total fluence in the 15-150 keV\nband is 1.5 +- 0.03 x 10^-5 erg/cm2 and the 1-sec peak flux measured\nfrom T+50.19 sec in the 15-150 keV band is 6.1 +- 0.3 ph/cm2/sec.\nA fit to a simple power law gives a photon index of 1.59 +- 0.03\n(chi squared 64.87 for 57 d.o.f.).  All the quoted errors are at\nthe 90% confidence level.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/1090853/BA/",
  "circularId": 31312,
  "createdOn": 1640564274000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 211225B: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 211225B"
}