{
  "bibcode": "2023GCN.33328....1K",
  "body": "N. J. Klingler (GSFC/UMBC/CRESSTII), P. A. Evans (U Leicester),\nR. A. J. Eyles-Ferris (U Leicester), J.D. Gropp (PSU),\nJ. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),\nK. L. Page (U Leicester), D. M. Palmer (LANL),\nT. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (INAF-OAB) and\nM. A. Williams (PSU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 14:48:34 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 230216A (trigger=1154815).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 113.966, -8.015 which is \n   RA(J2000) = 07h 35m 52s\n   Dec(J2000) = -08d 00' 53\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex\nstructure with a duration of about 20 sec.  The peak count rate\nwas ~700 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 14:50:15.1 UT, 100.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 113.95924, -8.01160\nwhich is equivalent to:\n   RA(J2000)  = 07h 35m 50.22s\n   Dec(J2000) = -08d 00' 41.8\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 27 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 3.17\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 105 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\n0.197. \n\nThe XRT position is 3.8\" from the galaxy WISEA J073550.15-080045.2\n\nBurst Advocate for this burst is N. J. Klingler (noelklin AT umbc.edu). \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": 33328,
  "createdOn": 1676559920000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 230216A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 230216A"
}