{
  "body": "M. J. Moss (GSFC),\nS. D. Barthelmy (GSFC), \nA. D'Ai (INAF-IASFPA),\nH. A. Krimm (NSF),\nS. Laha (GSFC/UMBC),\nA. Y. Lien (U Tampa),\nC. B. Markwardt (GSFC),\nD. M. Palmer (LANL),\nT. Parsotan (GSFC/UMBC),\nT. Sakamoto (AGU),\nM. 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 230903A (trigger #1189514)\n(D'Ai, et al., GCN Circ. 34610).  The BAT ground-calculated position is\nRA, Dec = 9.898, -40.910 deg which is \n   RA(J2000)  =  00h 39m 35.5s \n   Dec(J2000) = -40d 54' 34.5\" \nwith an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 40%.\n \nThe mask weighted light curve shows a single short pulse. T90 (15-350 keV) is 2.54 +- 0.27 sec (estimated error including systematics). \nThe T90 and the spectral hardness of this burst places it on the border of the long-soft and hard-short burst classifications. \n \nThe time-averaged spectrum from T+0.20 to T+2.93 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index -0.66 +- 1.49, \nand Epeak of 63.4 +- 17.8 keV (chi squared 44.41 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 2.2 +- 0.4 x 10^-07 erg/cm2\nand the 1-sec peak flux measured from T+0.50 sec in the 15-150 keV band is\n1.3 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.40 +- 0.21 (chi squared 54.66 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\nhttp://gcn.gsfc.nasa.gov/notices_s/1189514/BA/",
  "circularId": 34623,
  "eventId": "GRB 230903A",
  "createdOn": 1693886846659,
  "subject": "GRB 230903A: Swift-BAT refined analysis",
  "bibcode": "2023GCN.34623....1M",
  "submittedHow": "web",
  "submitter": "Mike Moss at George Washington U <mikejmoss3@gmail.com>"
}