{
  "bibcode": "2022GCN.32191....1C",
  "body": "S. B. Cenko (GSFC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),\nV. D'Elia (SSDC & INAF-OAR), J.D. Gropp (PSU), J. A. Kennea (PSU),\nS. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC),\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 18:01:51 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 220611A (trigger=1110090).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec  66.526d, -37.289d which is \n   RA(J2000) = 04h 26m 06s\n   Dec(J2000) = -37d 17' 20\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  Due to a telemetry gap, the BAT onboard\nlightcurve is not immediately available.  However, the triggering\nalgorithm found the source in an 8 second image, indicating a\nlong GRB. \n\nThe XRT began observing the field at 18:04:20.4 UT, 149.2 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 66.51418, -37.25899\nwhich is equivalent to:\n   RA(J2000)  = 04h 26m 03.40s\n   Dec(J2000) = -37d 15' 32.4\"\nwith an uncertainty of 1.9 arcseconds (radius, 90% containment). This\nlocation is 113 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.  We cannot determine whether the source\nis 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 2.66\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 152 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 none of\nthe XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.033. \n\nWe note that this source location is ~15 arcsec from the line of sight\nto the galaxy MCG-06-10-007, which is described in Simbad\nas an S0 galaxy, B=16.3, z~0.049, angular size 18\"x16\". \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": 32191,
  "createdOn": 1654972561000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 220611A: Swift detection of a burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 220611A"
}