{
  "bibcode": "2015GCN.17950....1M",
  "body": "F. E. Marshall (NASA/GSFC), A. Y. Lien (GSFC/UMBC),\nD. Malesani (DARK/NBI) and K. L. Page (U Leicester) report on behalf\nof the Swift Team:\n\nAt 11:28:58 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated either Sco X-1 or a source near Sco X-1. Swift slewed \nimmediately to the source. The BAT on-board calculated location is \nRA, Dec 245.071, -15.691 which is \n   RA(J2000) = 16h 20m 17s\n   Dec(J2000) = -15d 41' 26\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty). The BAT position is 6.1 arcmin from \nSco X-1. This was a 64 s image trigger with significance of \n17.7 sigma. As is usual with an image trigger, the available BAT \nlight curve shows no significant structure. \n\nThe source centroided on by the XRT is Sco X-1. This is, however, 363 arcsec \nfrom the BAT position, and thus outside the BAT error circle. We cannot \ndetermine at this time whether there is a new X-ray source within the BAT \nerror circle. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 185 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 BAT error circle. The 8'x8' region for the list of sources\ngenerated on-board covers 100% of the BAT error circle. No correction has\nbeen made for the expected extinction corresponding to E(B-V) of 0.38. \n\nWe await the full downlinked dataset to make a more definitive \nstatement on the nature of this trigger. \n\nBurst Advocate for this burst is F. E. Marshall (marshall 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": 17950,
  "createdOn": 1434888119000,
  "email": "marshall@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 645340: a possible GRB",
  "submitter": "Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>"
}