{
  "bibcode": "2025GCN.40565....1G",
  "submittedHow": "web",
  "format": "text/plain",
  "body": "R. Gupta (GSFC), S. D. Barthelmy (GSFC), \nR. A. J. Eyles-Ferris (U Leicester), H. A. Krimm (NSF),\nS. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),\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-239 to T+200 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 250520A (trigger #1315630)\n(Eyles-Ferris, et al., GCN Circ. 40491).  The BAT ground-calculated position is\nRA, Dec = 282.265, -11.852 deg which is \n   RA(J2000)  =  18h 49m 03.6s \n   Dec(J2000) = -11d 51' 08.6\" \nwith an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 68%.\n \nThe mask-weighted BAT light curve exhibits a single pulsed emission. \nT90 (15-350 keV) is 0.46 +- 0.15 sec (estimated error including systematics).\n \nThe time-averaged spectrum from T-0.33 to T+0.23 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n0.55 +- 0.23.  The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-07 erg/cm2.\nThe 1-sec peak photon flux measured from T-0.54 sec in the 15-150 keV band\nis 1.9 +- 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/1315630",
  "eventId": "GRB 250520A",
  "circularId": 40565,
  "createdOn": 1748463095737,
  "subject": "GRB 250520A: Swift-BAT refined analysis",
  "submitter": "Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>"
}