{
  "bibcode": "2019GCN.23615....1S",
  "body": "E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), D. N. Burrows (PSU), C. Gronwall (PSU),\nN. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC) and\nK. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 13:34:44 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 190106A (trigger=882252).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 29.886, +23.857, which is \n   RA(J2000)  =  01h 59m 33s\n   Dec(J2000) = +23d 51' 24\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows multiple peaks\nwith a duration of about 100 sec.  The peak count rate\nwas ~4000 counts/sec (15-350 keV), at ~10 sec after the trigger. \n\nThe XRT began observing the field at 13:36:06.3 UT, 81.8 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source located at RA, Dec 29.87964, 23.84516 which\nis equivalent to:\n   RA(J2000)  = 01h 59m 31.11s\n   Dec(J2000) = +23d 50' 42.6\"\nwith an uncertainty of 3.7 arcseconds (radius, 90% containment). This\nlocation is 47 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://www.swift.ac.uk/sper.  We\ncannot determine whether the source is fading at the present time. No\nspectrum from the promptly downlinked event data is yet available to\ndetermine the column density. \n\nThe initial flux in the 0.1 s image was 1.98e-08 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t01:59:31.18 =  29.87993\n  DEC(J2000) = +23:50:44.0  =  23.84555\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 5.0\narc sec. from the center of the XRT error circle. The estimated magnitude is\n16.45 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.09. \n\nBurst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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": 23615,
  "createdOn": 1546782324000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 190106A: Swift detection of a burst with an optical counterpart",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 190106A"
}