{
  "submitter": "David Palmer at LANL <palmer@lanl.gov>",
  "createdOn": 1687061362545,
  "subject": "GRB 230618A: Swift detection of a burst",
  "eventId": "GRB 230618A",
  "circularId": 33989,
  "bibcode": "2023GCN.33989....1P",
  "body": "\nK. L. Page (U Leicester) and S. Laha (GSFC/UMBC) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 03:51:12 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 230618A (trigger=1175438).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is   \nRA, Dec 196.588, +3.306 which is \n   RA(J2000) = 13h 06m 21s\n   Dec(J2000) = +03d 18' 20\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  Due to a telemetry outage caused by\na recent storm in Guam, no further BAT data will be available\nuntil a ground station pass. \n\nUsing promptly downlinked data we find a bright, uncatalogued X-ray\nsource located at RA, Dec 196.60313, 3.30257 which is equivalent to:\n   RA(J2000)  = 13h 06m 24.75s\n   Dec(J2000) = +03d 18' 09.3\"\nwith an uncertainty of 5.8 arcseconds (radius, 90% containment). This\nposition may be improved as more data are received; the latest position\nis available at https://www.swift.ac.uk/sper. No spectrum from the\npromptly downlinked event data is yet available to determine the column\ndensity. \n\nThe initial flux in the 2.5 s image was 6.46e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of nominal 150.000 seconds with the White\nfilter starting 137 seconds after the BAT trigger. No credible afterglow\ncandidate has been found in the initial data products. Data from the 2.7'x2.7'\nsub-image are not available at this time. The 8'x8' region for the list of\nsources generated on-board covers 100% of the XRT error circle. The list of\nsources is typically complete to about 18 mag. No correction has been made for\nthe expected extinction corresponding to E(B-V) of 0.025. \n\nBurst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). \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/)\n\n"
}