{
  "bibcode": "2021GCN.29893....1U",
  "body": "T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), H. A. Krimm (NSF),\nS. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL),\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 downlink,\nwe report further analysis of BAT GRB 210421A (trigger #1044426)\n(Moss et al., GCN Circ. 29849).  The BAT ground-calculated position is\nRA, Dec = 104.882, 4.928 deg which is\n   RA(J2000)  =  06h 59m 31.7s\n   Dec(J2000) = +04d 55' 41.2\"\nwith an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 44%.\n\nThe BAT light curve showed a complex structure with a duration of about ~60 sec.\nT90 (15-350 keV) is 79.52 +- 26.78 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-21.74 to T+73.22 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 1.10 +- 0.72,\nand Epeak of 35.2 +- 8.5 keV (chi squared 61.93 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-06 erg/cm2\nand the 1-sec peak flux measured from T+2.47 sec in the 15-150 keV band is\n2.0 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 2.10 +- 0.13 (chi squared 69.44 for 57 d.o.f.).  All the quoted errors\nare at the 90% confidence level.\n\nThe results of the batgrbproduct analysis are available at\nhttps://swift.gsfc.nasa.gov/results/BATbursts/1044426/bascript/top.html",
  "circularId": 29893,
  "createdOn": 1619196104000,
  "email": "sibasish.laha@nasa.gov",
  "eventId": "GRB 210421A",
  "subject": "GRB 210421A: Swift-BAT refined analysis",
  "submitter": "Sibasish Laha at GSFC  <sibasish.laha@nasa.gov>"
}