{
  "submitter": "Mike Moss at NASA GSFC <mikejmoss3@gmail.com>",
  "bibcode": "2024GCN.37539....1P",
  "createdOn": 1726616902944,
  "subject": "GRB 240912A: Swift-BAT refined analysis",
  "body": "T. Parsotan (GSFC), S. D. Barthelmy (GSFC), \nP. A. Evans (U Leicester), R. Gupta (GSFC),\nH. A. Krimm (NSF), S. Laha (GSFC/UMBC),\nA. Y. Lien (U Tampa), C. B. Markwardt (GSFC),\nM. J. Moss (GSFC), D. M. Palmer (LANL),\nD. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)\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 240912A (trigger #1253910)\n(P. A. Evans, et al., GCN Circ. 37466).  The BAT ground-calculated position is\nRA, Dec = 124.625, 33.999 deg which is \n   RA(J2000)  =  08h 18m 29.9s \n   Dec(J2000) = +33d 59' 56.2\" \nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 86%.\n \nThe light curve displays an interval of weak flat emission for ~45 seconds before\na bright multi-pulsed emission period. There is a possible shallow rise of emission\nat ~T0+280 seconds coincident with the flare seen in the XRT afterglow. \nT90 (15-350 keV) is 113.24 +- 7.83 sec (estimated error including systematics).\n \nThe time-averaged spectrum from T-2.35 to T+373.02 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 1.43 +- 0.11, \nand Epeak of 140.5 +- 41.0 keV (chi squared 27.79 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 3.4 +- 0.0 x 10^-05 erg/cm2\nand the 1-sec peak flux measured from T+76.05 sec in the 15-150 keV band is\n15.8 +- 0.5 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.68 +- 0.03 (chi squared 43.74 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/batgrbcat/BAT_refined_circular/1253910",
  "circularId": 37539,
  "format": "text/plain",
  "submittedHow": "web",
  "eventId": "GRB 240912A"
}