{
  "bibcode": "2019GCN.23648....1S",
  "body": "B. Sbarufatti (PSU), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),\nJ. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 11:56:09 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 190109B (trigger=882809).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 55.595, +63.578, which is \n   RA(J2000)  =  03h 42m 23s\n   Dec(J2000) = +63d 34' 40\"\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 10 sec.  The peak count rate\nwas ~1700 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 11:57:36.3 UT, 87.1 seconds after\nthe BAT trigger. No source was detected in the 2.5-s promptly available\nimage. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 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 25% of\nthe BAT 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\nBAT 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\n0.70. \n\nEven without an XRT detection, we believe this event to be a real GRB\ngiven an 8.6 sigma detection in BAT and that there is a temporal coincidence\nwith a Fermi-GBM event.  However there still is a possibility that this\nis not real.  We will have to wait for the full data set to be downlinked. \n\nBurst Advocate for this burst is B. Sbarufatti (bxs60 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": 23648,
  "createdOn": 1547036315000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 190109B: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 190109B"
}