{
  "bibcode": "2013GCN.15616....1O",
  "body": "S. R. Oates (UCL-MSSL), H. A. Krimm (CRESST/GSFC/USRA),\nN. P. M. Kuin (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of\nthe Swift Team:\n\nAt 04:44:51 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 131227A (trigger=582184).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 67.386, +28.864 which is \n   RA(J2000) = 04h 29m 33s\n   Dec(J2000) = +28d 51' 52\"\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 20 sec.  The peak count rate\nwas ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. \n\nThe XRT began observing the field at 04:45:48.0 UT, 57 seconds\nafter the BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 67.3781,\n28.8827 which is equivalent to:\n   RA(J2000)  = 04h 29m 30.74s\n   Dec(J2000) = +28d 52' 57.9\"\nwith an uncertainty of 2.2 arcseconds (radius, 90% containment). This\nposition may be improved as more data are received; the latest position\nis 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 in excess of the Galactic value (1.53 x\n10^21 cm^-2, Kalberla et al. 2005), with an excess column of 2.1\n(+2.23/-1.94) x 10^21 cm^-2 (90% confidence). \n\nThe initial flux in the 2.5 s image was 6.01e-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 66 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\n1.02. \n\nBurst Advocate for this burst is S. R. Oates (samantha.oates AT 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": 15616,
  "createdOn": 1388120985000,
  "email": "siegel@swift.psu.edu",
  "subject": "GRB 131227A: Swift detection of a burst",
  "submitter": "Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>",
  "eventId": "GRB 131227A"
}