{
  "bibcode": "2020GCN.26993....1E",
  "body": "P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),\nN. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),\nF. E. Marshall (NASA/GSFC), M. J. Moss (GWU), K. L. Page (U Leicester)\nand A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels\nSwift Observatory Team:\n\nAt 19:21:43 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200205B (trigger=954519 and 954520).  Swift slewed\nto the burst after a short delay. \nThe BAT on-board calculated location is \nRA, Dec 107.861, -56.506 which is \n   RA(J2000) = 07h 11m 27s\n   Dec(J2000) = -56d 30' 21\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a peak about 20 \nseconds long (trigger 954519) followed by a brighter more complex \npeak structure 350 s later (trigger 954520) with a peak countrate\nof 3500 counts/s.  Due to the double trigger, the complete\nBAT lightcurve is not immediately available. \n\nThe XRT began observing the field at 19:27:26.3 UT, 342.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 107.7881,\n-56.4875 which is equivalent to:\n   RA(J2000)  = 07h 11m 09.14s\n   Dec(J2000) = -56d 29' 15.0\"\nwith an uncertainty of 2.8 arcseconds (radius, 90% containment). This\nlocation is 37 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 https://www.swift.ac.uk/sper.  We\ncannot determine whether the source is fading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 1.04\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nThe initial flux in the 2.5 s image was 1.26e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 351 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t07:11:09.15 = 107.78811\n  DEC(J2000) = -56:29:15.1  = -56.48753\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 0.8\narc sec. from the center of the XRT error circle. The estimated magnitude is\n16.43 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.11. \n\nBurst Advocate for this burst is P. A. Evans (pae9 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/)",
  "circularId": 26993,
  "createdOn": 1580931961000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 200205B: Swift detection of a burst with optical counterpart",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 200205B"
}