{
  "bibcode": "2017GCN.21042....1B",
  "body": "A. P. Beardmore (U Leicester), N. P. M. Kuin (UCL-MSSL),\nK. L. Page (U Leicester), D. M. Palmer (LANL),\nB. Sbarufatti (INAF-OAB/PSU) and R. L. C. Starling (U Leicester)\nreport on behalf of the Swift Team:\n\nAt 09:13:42 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 170428A (trigger=750298).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 330.063, +26.918 which is \n   RA(J2000) = 22h 00m 15s\n   Dec(J2000) = +26d 55' 03\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single peak\nstructure with a duration of about 0.25 sec.  The peak count rate\nwas ~22000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 09:15:06.9 UT, 84.6 seconds after\nthe BAT trigger. Swift then passed into the SAA, during which time no\ndata are collected.  No source was detected in 208 s of promptly downlinked\ndata. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of  84 seconds with the U filter starting\n866 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers 25% of the\nBAT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The\n8'x8' region for the list of sources generated on-board covers 100% of the BAT\nerror circle. The list of sources is typically complete to about 18.0 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.06. \n\nBurst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). \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": 21042,
  "createdOn": 1493372295000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 170428A: Swift detection of a short burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 170428A"
}