{
  "bibcode": "2009GCN.10097....1G",
  "body": "D. Grupe (PSU), J. R. Cummings (NASA/UMBC),\nF. E. Marshall (NASA/GSFC), C. Pagani (PSU), D. M. Palmer (LANL),\nM. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC),\nT. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the\nSwift Team:\n\nAt 03:53:22 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 091029 (trigger=374210).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 60.183, -55.994 which is \n   RA(J2000) = 04h 00m 44s\n   Dec(J2000) = -55d 59' 37\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a double-peaked\nstructure with a duration of about 50 sec.  The peak count rate\nwas ~3000 counts/sec (15-350 keV), at ~18 sec after the trigger. \n\nThe XRT began observing the field at 03:54:41.9 UT, 79.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 60.17774, -55.95574 which\nis equivalent to:\n   RA(J2000)  = 04h 00m 42.66s\n   Dec(J2000) = -55d 57' 20.7\"\nwith an uncertainty of 4.4 arcseconds (radius, 90% containment). This\nlocation is 138 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 consistent with the Galactic value of\n1.14e+20 cm^-2 (Kalberla et al. 2005). \n\nThe initial flux in the 2.5 s image was 1.80e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t04:00:42.58 = 60.17742\n  DEC(J2000) = -55:57:20.0  = -55.95555\nwith a 90%-confidence error radius of about 0.70 arc sec. This position is 2.3\narc sec. from the center of the XRT error circle. The estimated magnitude is\n20.31 with a 1-sigma error of about 0.18. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.02. \n\n\n\n\nBurst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). \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": 10097,
  "createdOn": 1256789112000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 091029: Swift detection of a burst with an optical counterpart",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 091029"
}