{
  "bibcode": "2020GCN.27297....1C",
  "body": "S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), C. Gronwall (PSU),\nJ.D. Gropp (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST),\nA. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU),\nK. L. Page (U Leicester), D. M. Palmer (LANL) and\nA. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 02:34:57 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200303A (trigger=959431).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 212.698, +51.360, which is \n   RA(J2000)  =  14h 10m 47s\n   Dec(J2000) = +51d 21' 35\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a multi-peak\nstructure with a duration of about 60 sec.  The peak count rate\nwas ~3500 counts/sec (15-350 keV), at ~1 sec after the trigger. \n\nThe XRT began observing the field at 02:36:25.1 UT, 87.7 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 212.7173, 51.3583 which is equivalent to:\n   RA(J2000)  = 14h 10m 52.15s\n   Dec(J2000) = +51d 21' 29.9\"\nwith an uncertainty of 4.7 arcseconds (radius, 90% containment). This\nlocation is 43 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nThe initial flux in the 2.5 s image was 8.77e-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 96 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 100% of\nthe XRT 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\nXRT 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\n0.02. \n\nThis source lies within the current (Sector 22) field-of-view of TESS camera 3. \n\nBurst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). \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": 27297,
  "createdOn": 1583203765000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 200303A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 200303A"
}