{
  "bibcode": "2022GCN.31968....1S",
  "body": "M. Stamatikos (OSU) S. D. Barthelmy (GSFC),\nA. D'Ai (INAF-IASFPA), H. A. Krimm (NSF),\nS. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL),\nT. Parsotan (GSFC/UMBC), T. Sakamoto (AGU)\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 220427A (trigger #1104343)\n(D'Ai et al., GCN Circ. 31960).  The BAT ground-calculated position is\nRA, Dec = 275.922, -56.257 deg which is\n   RA(J2000)  =  18h 23m 41.2s\n   Dec(J2000) = -56d 15' 23.7\"\nwith an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 62%.\n\nThe mask-weighted light curve shows a single-peaked structure that\nstarts at ~T+3 s and peaks at ~T+8 s, and followed by a long tail\nemission that ends at ~T+70 s. T90 (15-350 keV) is 57.2 +- 12.2 sec\n(estimated error including systematics).\n\nThe time-averaged spectrum from T+3.09 to T+68.06 sec is best fit\nby a simple power-law model.  The power law index of the time-averaged\nspectrum is 1.23 +- 0.13.  The fluence in the 15-150 keV band is\n2.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from\nT+7.83 sec in the 15-150 keV band is 3.0 +- 0.3 ph/cm2/sec.\nAll the quoted errors are at the 90% confidence level.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/1104343/BA/",
  "circularId": 31968,
  "createdOn": 1651239922000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 220427A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 220427A"
}