{
  "bibcode": "2017GCN.21135....1G",
  "body": "J.G. Gropp (PSU), S. D. Barthelmy (GSFC), C. Gronwall (PSU),\nJ. A. Kennea (PSU), H. A. Krimm (NSF/USRA), N. P. M. Kuin (UCL-MSSL),\nA. Y. Lien (GSFC/UMBC) and D. M. Palmer (LANL) report on behalf of the\nSwift Team:\n\nAt 19:49:15 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 170524A (trigger=754322).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 319.456, +48.587, which is \n   RA(J2000)  =  21h 17m 49s\n   Dec(J2000) = +48d 35' 15\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single peak\nwith a duration of about 0.25 sec.  The peak count rate\nwas ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 19:50:16.0 UT, 60.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 319.4869, 48.6065 which\nis equivalent to:\n   RA(J2000)  = 21h 17m 56.86s\n   Dec(J2000) = +48d 36' 23.4\"\nwith an uncertainty of 4.1 arcseconds (radius, 90% containment). This\nlocation is 101 arcseconds from the BAT onboard position, within the\nBAT error circle. This position may be improved as more data are\nreceived; the latest position is available at\nhttp://www.swift.ac.uk/sper.  We cannot determine whether the source is\nfading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata does not constrain the column density. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 67 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 large, but uncertain extinction expected. \n\nWe note that this is a short burst, close to the Galactic plane \n(lat = -0.5 degrees), although far from the Galactic center\n(lon = 91 degrees).  Thus there is a possibility that this\nis a previously unknown Soft Gamma Repeater (SGR). \nHowever, the preliminary 4-energy lightcurve shows more\nflux above 100 keV than is typical for an SGR burst. \n\nBurst Advocate for this burst is J.G. Gropp (jdg44 AT psu.edu). \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": 21135,
  "createdOn": 1495656388000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 170524A: Swift detection of a burst (or possible new SGR)",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 170524A"
}