{
  "bibcode": "2022GCN.31347....1T",
  "body": "A. Tohuvavohu (U Toronto), J.D. Gropp (PSU), J. A. Kennea (PSU),\nA. Y. Lien (U Tampa), D. M. Palmer (LANL),\nT. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (PSU) and\nM. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 05:09:55 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 220101A (trigger=1091101).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 1.380, +31.753 which is \n   RA(J2000) = 00h 05m 31s\n   Dec(J2000) = +31d 45' 09\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT lightcurve shows a complex lightcurve\nextending to at least T+170 with a peak of 7000 counts/s (15-350 keV), \nat ~89 sec after the trigger. \n\nThe XRT began observing the field at 05:11:32.2 UT, 80.8 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 1.3561, 31.7702 which is equivalent to:\n   RA(J2000)  = 00h 05m 25.46s\n   Dec(J2000) = +31d 46' 12.7\"\nwith an uncertainty of 4.7 arcseconds (radius, 90% containment). This\nlocation is 95 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 1.30e-08 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 89 seconds after the BAT trigger. There is a candidate afterglow in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t00:05:24.82 =\t1.35340\n  DEC(J2000) = +31:46:08.5  =  31.76903\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 9.3\narc sec. from the center of the XRT error circle. The estimated magnitude is\n14.60 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.056. \n\nBurst Advocate for this burst is A. Tohuvavohu (aaron.tohu 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": 31347,
  "createdOn": 1641015160000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 220101A: Swift detection of a burst with a bright optical counterpart",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 220101A"
}