{
  "bibcode": "2018GCN.22828....1P",
  "body": "K. L. Page (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nA. Deich (PSU), S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU),\nF. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 16:41:56 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 180623A (trigger=844015).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 214.511, -60.294, which is \n   RA(J2000)  =  14h 18m 03s\n   Dec(J2000) = -60d 17' 38\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows 4 large peaks and many\nlittle peaks with a total duration of about 90 sec.  The peak count rate\nwas ~6500 counts/sec (15-350 keV), at ~61 sec after the trigger. \n\nThe XRT began observing the field at 16:43:13.3 UT, 76.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 214.5295,\n-60.2539 which is equivalent to:\n   RA(J2000)  = 14h 18m 07.08s\n   Dec(J2000) = -60d 15' 13.9\"\nwith an uncertainty of 2.1 arcseconds (radius, 90% containment). This\nlocation is 148 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\nhttp://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata does not constrain the column density. \n\nThe initial flux in the 2.5 s image was 1.31e-08 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of nominal 150.000 seconds with the\nWhite  filter starting 85 seconds after the BAT trigger. No credible\nafterglow  candidate has been found in the initial data products. The\n2.7'x2.7'  sub-image covers 100% of the XRT error circle. The 8'x8'\nregion for the list of  sources generated on-board covers 100% of the\nXRT error circle. The typical 3-sigma upper limit has been about 19.6\nmag. The list of  sources is typically complete to about 18 mag. No\ncorrection has been made for  the large, but uncertain, extinction\nexpected. \n\nAlthough this source is close to the Galactic plane (lat = 0.83 degrees), \nits distance from the Galactic center (46 degrees), the presence \nof significant flux above 100 keV, and the complexity and overall\nshape of the lightcurve are consistent with a GRB that is aligned\nwith the plane due to random coincidence. \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/too.html.)",
  "circularId": 22828,
  "createdOn": 1529773240000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 180623A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 180623A"
}