{
  "bibcode": "2025GCN.40812....1L",
  "submittedHow": "web",
  "createdOn": 1750678754482,
  "format": "text/plain",
  "submitter": "Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>",
  "body": "S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), R. Gupta (GSFC),\nH. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),\nM. J. Moss (GSFC), K. L. Page (U Leicester),  D. M. Palmer (LANL),\nT. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-273 to T+962 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 250617B (trigger #1325580)\n(Page, et al., GCN Circ. 40760).  The BAT ground-calculated position is\nRA, Dec = 332.883, 32.721 deg which is\n   RA(J2000)  =  22h 11m 31.8s\n   Dec(J2000) = +32d 43' 14.5\"\nwith an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 10%.\n\nThe mask-weighted light curve shows two peaks.  The emission starts at\nT-30 sec, peaks at T+1 sec, and ends at T+18 sec.\nT90 (15-350 keV) is 36.5 +- 6.9 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-29.32 to T+14.30 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n2.13 +- 0.22.  The fluence in the 15-150 keV band is 2.3 +- 0.3 x 10^-6 erg/cm2.\nThe 1-sec peak photon flux measured from T+0.19 sec in the 15-150 keV band\nis 2.9 +- 0.8 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/1325580",
  "circularId": 40812,
  "eventId": "GRB 250617B",
  "subject": "GRB 250617B: Swift-BAT refined analysis"
}