{
  "submittedHow": "web",
  "createdOn": 1766639347476,
  "body": "A. Y. Lien (U Tampa), E. Ambrosi (INAF-IASFPA),\nS. D. Barthelmy (GSFC), R. Gupta (GSFC),\nH. A. Krimm (NSF), S. Laha (GSFC/UMBC),\nC. B. Markwardt (GSFC), M. J. Moss (GSFC),\nD. M. Palmer (LANL), T. Parsotan (GSFC),\nD. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)\n(i.e. the Swift-BAT team):\n \nUsing the data set from T-240 to T+962 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 251221A (trigger #1426088)\n(Ambrosi, et al., GCN Circ. 43166).  The BAT ground-calculated position is\nRA, Dec = 101.422, 0.738 deg which is \n   RA(J2000)  =  06h 45m 41.4s \n   Dec(J2000) = +00d 44' 15.8\" \nwith an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 42%.\n \nThe mask-weighted light curves displays a complicated multi-pulsed light curve.\nThe T90 (15-350 keV) is 56.86 +- 7.05 sec (estimated error including systematics).\n \nThe time-averaged spectrum from T-38.10 to T+27.74 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.25 +- 0.13.  The fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-06 erg/cm2.\nThe 1-sec peak photon flux measured from T+2.91 sec in the 15-150 keV band\nis 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel. \n \nThe results of the batgrbproduct analysis are available at\nhttps://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1426088",
  "format": "text/plain",
  "circularId": 43234,
  "subject": "GRB 251221A: Swift-BAT refined analysis",
  "submitter": "Mike Moss at NASA GSFC <mikejmoss3@gmail.com>",
  "bibcode": "2025GCN.43234....1L",
  "eventId": "GRB 251221A"
}