{
  "bibcode": "2017GCN.21143....1L",
  "body": "A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), J.G. Gropp (PSU),\nH. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),\nD. M. Palmer (LANL), T. Sakamoto (AGU),\nM. Stamatikos (OSU), T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-61 to T+242 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 170524A (trigger #754322)\n(Gropp et al., GCN Circ. 21135).  The BAT ground-calculated position is\nRA, Dec = 319.488, 48.603 deg which is\n  RA(J2000)  =  21h 17m 57.2s\n  Dec(J2000) = +48d 36' 12.5\"\nwith an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 96%.\n\nThe mask-weighted light curve shows a double peaked structure\nwith the first pulse from ~T0 to ~T+0.05, and second pulse from ~T+0.05 to ~T+0.1.\nT90 (15-350 keV) is 0.10 +- 0.02 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T+0.00 to T+0.12 sec fit by a simple\npower-law model shows the power law index of 1.07 +- 0.24 (chi squared 47.68 for 57 d.o.f.).\nThe fluence in the 15-150 keV band is 3.7 +- 0.6 x 10^-8 erg/cm2.\nThe 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band\nis 0.5 +- 0.1 ph/cm2/sec.\n\nA single blackbody fit to the time-averaged spectrum shows the blackbody\ntemperature of 21.09 +- 3.99 keV (chi squared 51.91 for 57 d.o.f.).\nA thermal bremsstrahlung model fit shows the temperature of 199.36 +- -80.44 keV\n(chi squared 57.87 for 57 d.o.f.).  A double blackbody fit shows the lower temperature\nof 5.84 (error not unconstrained) keV and the higher temperature of 25.96 +15.56 keV\n(chi squared 45.99 for 55 d.o.f.).  All the quoted errors are at the 90% confidence level.\n\nThe photon index of ~ 1 using the simple power-law model is consistent with those from\nthe BAT-detected short GRBs (Lien & Sakamoto et al. 2016), and harder than\nthe spectra of many BAT-detected SGRs, which have photon index ~ 3.\nIn addition, the double-peaked structure seen in this burst is not commonly observed in\nthe BAT light curves of SGRs (with time bins >= 2 ms).\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/754322/BA/",
  "circularId": 21143,
  "createdOn": 1495738439000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 170524A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 170524A"
}