{
  "bibcode": "2015GCN.18280....1S",
  "body": "R. L. C. Starling (U Leicester), S. D. Barthelmy (GSFC),\nD. N. Burrows (PSU), V. D'Elia (ASDC), H. A. Krimm (CRESST/GSFC/USRA),\nF. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 18:40:21 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 150911A (trigger=655262).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 67.424, +5.743, which is \n   RA(J2000)  =  04h 29m 42s\n   Dec(J2000) = +05d 44' 34\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a pair of overlapping peaks\nwith a total duration of about 12 sec.  The peak count rate\nwas ~5000 counts/sec (15-350 keV), at ~4 sec after the trigger. \n\nThe XRT began observing the field at 18:41:41.3 UT, 79.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source with an enhanced position: RA, Dec 67.4331,\n5.7350 which is equivalent to:\n   RA(J2000)  = 04h 29m 43.95s\n   Dec(J2000) = +05d 44' 05.9\"\nwith an uncertainty of 2.3 arcseconds (radius, 90% containment). This\nlocation is 43 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 1.87\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 82 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\n0.32. \n\nBurst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.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": 18280,
  "createdOn": 1441997733000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 150911A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 150911A"
}