{
  "bibcode": "2020GCN.27102....1D",
  "body": "P. D'Avanzo (INAF-OAB), M. G. Bernardini (INAF-OAB), J.D. Gropp (PSU),\nJ. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),\nT. Sbarrato (INAF-OAB) and A. Tohuvavohu (U Toronto) report on behalf\nof the Neil Gehrels Swift Observatory Team:\n\nAt 13:32:33 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200216B (trigger=956824).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 160.461, +19.454 which is \n   RA(J2000) = 10h 41m 51s\n   Dec(J2000) = +19d 27' 15\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed one long peak\nwith a duration of about 30 sec, there is possible evidence for weaker \nemission out to T0+60 seconds. The peak count rate was ~2000 counts/sec \n(15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 13:34:29.0 UT, 115.1 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n160.4343, 19.4757 which is equivalent to:\n   RA(J2000)  = 10h 41m 44.23s\n   Dec(J2000) = +19d 28' 32.4\"\nwith an uncertainty of 2.0 arcseconds (radius, 90% containment). This\nlocation is 119 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (2.03 x\n10^20 cm^-2, Willingale et al. 2013), with an excess column of 9.9\n(+3.22/-2.80) x 10^21 cm^-2 (90% confidence). \n\nThe initial flux in the 2.5 s image was 1.33e-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 124 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\nBurst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT inaf.it). \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": 27102,
  "createdOn": 1581861464000,
  "email": "paolo.davanzo@inaf.it",
  "subject": "GRB 200216B: Swift detection of a burst",
  "submitter": "Paolo D'Avanzo at INAF - OAB  <paolo.davanzo@inaf.it>",
  "eventId": "GRB 200216B"
}