{
  "eventId": "GRB 230510A",
  "bibcode": "2023GCN.33880....1L",
  "circularId": 33880,
  "createdOn": 1685107656974,
  "body": "S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), R. A. J. Eyles-Ferris (U Leicester),\nH. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL),\nT. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU)\n(i.e. the Swift-BAT team):\n Using the data set from T-240 to T+349 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 230510A (trigger #1167973)\n(Eyles-Ferris, et al., GCN Circ. 33752).  The BAT ground-calculated position is\nRA, Dec = 318.138, 34.430 deg which is\n   RA(J2000)  =  21h 12m 33.2s\n   Dec(J2000) = +34d 25' 49.8\"\nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 100%.\n The mask-weighted light curve shows a precursor starting at T-150 s with\na duration of ~20 s.  The bright main episode starts at T-10 s, peaks at\nT+15 s, and ends at T+60 s.  T90 (15-350 keV) is 178.4 +- 6.9 sec\n(estimated error including systematics).\n The time-averaged spectrum from T-145.6 to T+56.8 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.60 +- 0.09.  The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-5 erg/cm2.\nThe 1-sec peak photon flux measured from T+13.39 sec in the 15-150 keV band\nis 5.9 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel.\n The results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/1167973/BA/\n",
  "subject": "GRB 230510A: Swift-BAT refined analysis",
  "submitter": "Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>"
}