{
  "bibcode": "2016GCN.19912....1C",
  "body": "J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),\nA. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA),\nV. D'Elia (ASDC), S. W. K Emery (UCL-MSSL), J. A. Kennea (PSU),\nN. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),\nB. Mingo (U Leicester), K. L. Page (U Leicester) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 16:07:43 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 160912A (trigger=711914).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 301.518, +57.543, which is \n   RA(J2000)  =  20h 06m 04s\n   Dec(J2000) = +57d 32' 36\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is typical for image triggers, the BAT light curve\ndoes not show anything significant over the trigger window.  However, at ~T+150 sec\nthere is a flare in the light curve (~1300 cnts/sec). \n\nThe XRT began observing the field at 16:09:57.0 UT, 134.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find a fading,\nuncatalogued X-ray source with an enhanced position: RA, Dec 301.4981,\n57.5655 which is equivalent to:\n   RA(J2000)  = 20h 05m 59.56s\n   Dec(J2000) = +57d 33' 55.8\"\nwith an uncertainty of 2.1 arcseconds (radius, 90% containment). This\nlocation is 89 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\nWe note the presence in the XRT raw light curve of a large X-ray flare \ncoincident with the BAT flare mentioned above. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 2.35\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 137 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\n0.20. \n\nBurst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). \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": 19912,
  "createdOn": 1473698376000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 160912A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 160912A"
}