{
  "bibcode": "2009GCN..9905....1U",
  "body": "T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC), M. M. Chester (PSU),\nS. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),\nV. Mangano (INAF-IASFPA), K. L. Page (U Leicester),\nP. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC),\nB. Sbarufatti (INAF-IASFPA), R. L. C. Starling (U Leicester) and\nE. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:\n\nAt 15:50:29 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 090912 (trigger=362633).  Swift executed a delayed slewed\nto the burst. \nThe BAT on-board calculated location is \nRA, Dec 188.092, +61.513, which is \n   RA(J2000)  =  12h 32m 22s\n   Dec(J2000) = +61d 30' 45\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows two peaks at T+0 and\nat T+90 with a total duration of about 130 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger. \n\nThe XRT began observing the field at 16:03:42.4 UT, 792.6 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 188.0422, 61.4843 which\nis equivalent to:\n   RA(J2000)  = 12h 32m 10.13s\n   Dec(J2000) = +61d 29' 03.5\"\nwith an uncertainty of 2.2 arcseconds (radius, 90% containment). This\nlocation is 134 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 (1.28e+20\ncm^-2, Kalberla et al. 2005), with an excess column of 6.2\n(+4.43/-3.60) x 10^21 cm^-2 (90% confidence). \n\n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 795 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 expected\nextinction corresponding to E(B-V) of 0.01. \n\n\n\n\nBurst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). \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": 9905,
  "createdOn": 1252772111000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090912: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090912"
}