{
  "bibcode": "2020GCN.27254....1L",
  "body": "S. Laha (GSFC/UMBC/CRESST), S. D. Barthelmy (GSFC),\nP. A. Evans (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU) and\nK. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 11:14:41 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200228B (trigger=958733).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 252.026, +16.960, which is \n   RA(J2000)  =  16h 48m 06s\n   Dec(J2000) = +16d 57' 37\"\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 25 sec.  The peak count rate\nwas ~2000 counts/sec (15-350 keV), at ~5 sec after the trigger. \n\nThe XRT began observing the field at 11:16:56.8 UT, 135.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source located at RA, Dec 252.04730, 16.98505 which is equivalent\nto:\n   RA(J2000)  = 16h 48m 11.35s\n   Dec(J2000) = +16d 59' 06.2\"\nwith an uncertainty of 5.7 arcseconds (radius, 90% containment). This\nlocation is 116 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\nhttps://www.swift.ac.uk/sper. No spectrum from the promptly downlinked\nevent data is yet available to determine the column density. \n\nUVOT data are unavailable at this time. \n\nBurst Advocate for this burst is S. Laha (sib.laha AT gmail.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/)",
  "circularId": 27254,
  "createdOn": 1582889250000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 200228B: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 200228B"
}