{
  "bibcode": "2015GCN.18643....1D",
  "body": "A. D'Ai (INAF-IASFPA), P. A. Evans (U Leicester),\nA. Maselli (INAF-IASFPA), K. L. Page (U Leicester),\nD. M. Palmer (LANL) and T. Sakamoto (AGU) report on behalf of the\nSwift Team:\n\nAt 09:08:49 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 151127A (trigger=665268).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 19.778, -82.774 which is \n   RA(J2000) = 01h 19m 07s\n   Dec(J2000) = -82d 46' 25\"\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 0.5 sec.  The peak count rate\nwas ~3000 counts/sec (15-350 keV), at ~0.15 sec after the trigger. \n\nThe XRT began observing the field at 09:10:09.0 UT, 79.2 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 19.4797, -82.7707 which\nis equivalent to:\n   RA(J2000)  = 01h 17m 55.13s\n   Dec(J2000) = -82d 46' 14.5\"\nwith an uncertainty of 2.6 arcseconds (radius, 90% containment). This\nlocation is 135 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.  We cannot determine whether the source is\nfading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 1.02\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 77 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 0.12. \n\nBurst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.inaf.it). \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": 18643,
  "createdOn": 1448616269000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 151127A: Swift detection of a short burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 151127A"
}