{
  "bibcode": "2009GCN..9854....1S",
  "body": "P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),\nJ. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),\nC. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),\nJ. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),\nC. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),\nC. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),\nA. Rowlinson (U Leicester), M. H. Siegel (PSU),\nM. Stamatikos (OSU/NASA/GSFC) and M. A. Stark (PSU) report on behalf\nof the Swift Team:\n\nAt 21:30:25 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 090831C (trigger=361489).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 108.278, -25.100 which is \n   RA(J2000)  =  07h 13m 07s\n   Dec(J2000) = -25d 06' 00\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single peak\nwith a duration of about 10 sec.  The peak count rate\nwas ~800 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 21:32:23.5 UT, 117.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source located at RA, Dec 108.29307, -25.11934 which\nis equivalent to:\n   RA(J2000)  = 07h 13m 10.34s\n   Dec(J2000) = -25d 07' 09.6\"\nwith an uncertainty of 3.8 arcseconds (radius, 90% containment). This\nlocation is 85 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of\n3.24e+21 cm^-2 (Kalberla et al. 2005). \n\n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 120 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. Results from the 2.7'x2.7' sub-image\nare not available at this time. The coverage of the XRT error circle by the\n8'x8' region for the list of sources generated on-board is uncertain because\nthe large number of sources filled the available telemetry. No correction has\nbeen made for the expected extinction corresponding to E(B-V) of 0.38. \n\n\n\n\nBurst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). \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": 9854,
  "createdOn": 1251754950000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090831C: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090831C"
}