{
  "bibcode": "2015GCN.17936....1L",
  "body": "A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL)\nand M. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 22:49:19 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 150616A (trigger=644259).  The Swift slewed to the burst\nafter a delay due to the Earth limb constraint. \nThe BAT on-board calculated location is \nRA, Dec 314.705, -53.394 which is \n   RA(J2000) = 20h 58m 49s\n   Dec(J2000) = -53d 23' 36\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex\nstructure with a duration of at least 200 sec.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 22:58:50.1 UT, 570.9 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 314.7156, -53.3923 which is equivalent to:\n   RA(J2000)  = +20h 58m 51.74s\n   Dec(J2000) = -53d 23' 32.3\"\nwith an uncertainty of 4.8 arcseconds (radius, 90% containment). This\nlocation is 23 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nThe initial flux in the 2.5 s image was 4.54e-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 579 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\n0.04. \n\nBurst Advocate for this burst is A. Y. Lien (amy.y.lien AT 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": 17936,
  "createdOn": 1434495981000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 150616A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 150616A"
}