{
  "bibcode": "2012GCN.13510....1D",
  "body": "P. D'Avanzo (INAF-OAB), W. H. Baumgartner (GSFC/UMBC),\nV. D'Elia (ASDC), H. A. Krimm (CRESST/GSFC/USRA),\nB. Sbarufatti (INAF-OAB/PSU) and M. Stamatikos (OSU/NASA/GSFC) report\non behalf of the Swift Team:\n\nAt 06:39:02 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 120724A (trigger=528443).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 245.190, +3.509 which is \n   RA(J2000) = 16h 20m 46s\n   Dec(J2000) = +03d 30' 33\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multi-peaked\nstructure with a duration of about 40 sec.  The peak count rate\nwas ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 06:40:52.0 UT, 109.1 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 245.18192, 3.50750 which\nis equivalent to:\n   RA(J2000)  = 16h 20m 43.66s\n   Dec(J2000) = +03d 30' 27.0\"\nwith an uncertainty of 4.0 arcseconds (radius, 90% containment). This\nlocation is 29 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://www.swift.ac.uk/sper.  We\ncannot determine whether the source is fading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 4.29\nx 10^20 cm^-2 (Kalberla et al. 2005). \n\nThe initial flux in the 2.5 s image was 5.14e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 117 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.05. \n\nBurst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it). \nPlease contact the BA by email if you require additional information\nregarding Swift followup of this burst. In extremely urgent cases, after\ntrying the Burst Advocate, you can contact the Swift PI by phone (see\nSwift TOO web site for information: http://www.swift.psu.edu/too.html.)",
  "circularId": 13510,
  "createdOn": 1343112625000,
  "email": "paolo.davanzo@brera.inaf.it",
  "subject": "GRB 120724A: Swift detection of a burst",
  "submitter": "Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>",
  "eventId": "GRB 120724A"
}