{
  "bibcode": "2018GCN.22682....1L",
  "body": "A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),\nJ. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),\nA. Tohuvavohu (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 19:46:13 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 180504A (trigger=830822).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 331.134, -14.655 which is \n   RA(J2000) = 22h 04m 32s\n   Dec(J2000) = -14d 39' 17\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a multi-peaked\nstructure with a duration of about 50 sec.  The peak count rate\nwas ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger. \n\nUsing promptly downlinked data we find a bright, uncatalogued X-ray\nsource located at RA, Dec 331.14235, -14.65988 which is equivalent to:\n   RA(J2000)  = 22h 04m 34.16s\n   Dec(J2000) = -14d 39' 35.6\"\nwith an uncertainty of 3.7 arcseconds (radius, 90% containment). This\nposition may be improved as more data are received; the latest position\nis available at http://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 3.50\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nThe initial flux in the 2.5 s image was 9.57e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 117 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\n0.04. \n\nBurst Advocate for this burst is A. Y. Lien (amy.y.lien 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/too.html.)",
  "circularId": 22682,
  "createdOn": 1525464191000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 180504A: Swift detection of a burst",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 180504A"
}