{
  "bibcode": "2017GCN.21251....1B",
  "body": "S. D. Barthelmy (GSFC), A. Cholden-Brown (PSU), A. D'Ai (INAF-IASFPA),\nV. D'Elia (ASDC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC) and\nB. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:\n\nAt 20:55:08 UT, the Swift Burst Alert Telescope (BAT) triggered on noise near\nIGR17303-0601 (trigger=756953).  Swift slewed immediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 262.731, -5.979, which is \n   RA(J2000)  =  17h 30m 56s\n   Dec(J2000) = -05d 58' 42\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is typical for image triggers, \nthere is nothing in the real-time light curve. \n\nThe XRT began observing the field at 20:59:25.9 UT, 257.1 seconds after\nthe BAT trigger. No source was detected in 631 s of promptly downlinked\ndata. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 261 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 25% of\nthe BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nResults from the list of sources generated on-board are not available at this\ntime. No correction has been made for the expected extinction corresponding to\nE(B-V) of 0.59. \n\nDue to the low significance of the image peak (5.98 sigma), the \nlarge distance to the potential associated source (8.5 arcminutes),\nthe lack of activity in the BAT count rates, and the non-detection \nby XRT, we believe that this is merely a noise fluctuation in\nthe image plane and not an astrophysical source.",
  "circularId": 21251,
  "createdOn": 1497302080000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 756953 is probably not an astrophysical source",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>"
}