{
  "bibcode": "2015GCN.17944....1K",
  "body": "J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 00:44:05 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated V404 Cyg.  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 306.012, +33.867 which is \n   RA(J2000) = 20h 24m 03s\n   Dec(J2000) = +33d 52' 01\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multi-peaked\nstructure with a duration of about 50 sec.  The peak count rate\nwas ~1300 counts/sec (15-350 keV), at ~20 sec after the trigger. \n\nThe XRT began observing the field at 00:45:12.7 UT, 67.7 seconds after\nthe BAT trigger. XRT found a bright X-ray source located at RA, Dec\n306.0163, 33.8645 which is equivalent to:\n   RA(J2000)  = +20h 24m 3.91s\n   Dec(J2000) = +33d 51' 52.2\"\nwith an uncertainty of 5.0 arcseconds (radius, 90% containment). This\nposition is 4.8 arcseconds from a known X-ray source: 1SXPS\nJ202404.2+335155. This source is in the Swift XRT 1SXPS catalogue with\na mean 0.3-10 keV count-rate of 0.0183 +/- 0.0015 ct/sec; see\nhttp://www.swift.ac.uk/1SXPS/1SXPSJ202404.2%2B335155 for details of\nthese previous observations. No event data are yet available to\ndetermine the column density using X-ray spectroscopy. \n\nThe initial flux in the 2.5 s image was 3.15e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 76 seconds after the BAT trigger. We detect V404 Cyg with a white\nmagnitude of 15.54 +- 0.14.  No correction has been made\nfor the large, but uncertain extinction expected.",
  "circularId": 17944,
  "createdOn": 1434589229000,
  "email": "kennea@swift.psu.edu",
  "subject": "Swift Trigger 644520 is V404 Cyg",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>"
}