{
  "bibcode": "2016GCN.19478....1K",
  "body": "D. Kocevski (NASA/GSFC/ORAU), P.A. Evans (U Leicester),\nN. Gehrels (NASA/GSFC), J. A. Kennea (PSU),\nH. A. Krimm (CRESST/GSFC/USRA), B. Mingo (U Leicester),\nK. L. Page (U Leicester), D. M. Palmer (LANL), T. G. R. Roegiers (PSU)\nand M. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 14:43:02 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 160601A (trigger=688452).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 235.034, +64.495 which is \n   RA(J2000) = 15h 40m 08s\n   Dec(J2000) = +64d 29' 41\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peaked\nstructure with a duration of about 0.2 sec.  The peak count rate\nwas ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 14:44:16.3 UT, 74.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 234.9351, 64.5401 which\nis equivalent to:\n   RA(J2000)  = 15h 39m 44.43s\n   Dec(J2000) = +64d 32' 24.2\"\nwith an uncertainty of 3.3 arcseconds (radius, 90% containment). This\nlocation is 223 arcseconds from the BAT onboard position. This position\nmay be improved as more data are received; the latest position is\navailable at http://www.swift.ac.uk/sper.  We cannot determine whether\nthe source is fading at the present time. This position is more than\n2-sigma away from the BAT position, and so possibly unrelated to the\ntrigger. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 2.04\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 250 seconds with the U filter\nstarting 78 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 XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. \n\nBurst Advocate for this burst is D. Kocevski (dankocevski AT gmail.com). \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": 19478,
  "createdOn": 1464793257000,
  "email": "palmer@lanl.gov",
  "eventId": "GRB 160601A",
  "subject": "GRB 160601A: Swift detection of a short hard burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>"
}