{
  "bibcode": "2012GCN.13602....1M",
  "body": "F. E. Marshall (NASA/GSFC), P. A. Evans (U Leicester),\nN. Gehrels (NASA/GSFC), B.P. Gompertz (U Leicester),\nC. Guidorzi (U Ferrara), J. A. Kennea (PSU),\nO. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC),\nK. L. Page (U Leicester), D. M. Palmer (LANL) and\nE. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:\n\nAt 07:09:37 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 120807A (trigger=530267).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 241.211, -47.490 which is \n   RA(J2000) = 16h 04m 51s\n   Dec(J2000) = -47d 29' 23\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single peak \nstructure with a duration of about 15 sec.  The peak count rate\nwas ~2000 counts/sec (15-350 keV), at ~2 sec after the trigger. \n\nThe XRT began observing the field at 07:10:49.4 UT, 71.6 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source with an enhanced position: RA, Dec 241.2594,\n-47.4797 which is equivalent to:\n   RA(J2000)  = 16h 05m 02.26s\n   Dec(J2000) = -47d 28' 47.0\"\nwith an uncertainty of 2.3 arcseconds (radius, 90% containment). This\nlocation is 123 arcseconds from the BAT onboard position, within the\nBAT error circle. This position may be improved as more data are\nreceived; the latest position is available at\nhttp://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (4.94 x\n10^21 cm^-2, Kalberla et al. 2005), with an excess column of 3.5\n(+4.80/-2.19) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 75 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 none of\nthe XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the large, but\nuncertain extinction expected. \n\nBurst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). \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": 13602,
  "createdOn": 1344324224000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 120807A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 120807A"
}