{
  "bibcode": "2020GCN.27373....1E",
  "body": "P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),\nN. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST),\nA. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), T. Sakamoto (AGU)\nand A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels\nSwift Observatory Team:\n\nAt 21:16:47 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a new SGR (trigger=960986).  \nSwift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 274.471, -16.102 which is \n   RA(J2000) = 18h 17m 53s\n   Dec(J2000) = -16d 06' 05\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peak\nstructure with a duration of about 0.1 sec.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 21:17:51.2 UT, 64.2 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 274.5009, -16.1312\nwhich is equivalent to:\n   RA(J2000)  = 18h 18m 00.22s\n   Dec(J2000) = -16d 07' 52.3\"\nwith an uncertainty of 2.4 arcseconds (radius, 90% containment). This\nlocation is 147 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. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata does not constrain the column density. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 68 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 large, but\nuncertain, extinction expected. \n\nThe extremely short and relatively soft nature of the BAT detection, combined \nwith the source's closeness to the Galactic Plane (b=-0.14 deg), is suggestive\nthat this trigger is from a previously undiscovered SGR. If this is a new SGR\nand not a GRB, we name the source Swift J1818.0-1607. \n\nBurst Advocate for this burst is P. A. Evans (pae9 AT star.le.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/)",
  "circularId": 27373,
  "createdOn": 1584049658000,
  "email": "pae9@star.le.ac.uk",
  "subject": "Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607",
  "submitter": "Phil Evans at U of Leicester  <pae9@star.le.ac.uk>"
}