{
  "bibcode": "2020GCN.28879....1G",
  "body": "J.D. Gropp (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),\nF. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on\nbehalf of the Neil Gehrels Swift Observatory Team:\n\nAt 09:45:06 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated SGR 1830-0645 (trigger=1005428).  Swift slewed immediately to \nthe source. The BAT on-board calculated location is \nRA, Dec 277.701, -6.741 which is \n   RA(J2000) = 18h 30m 48s\n   Dec(J2000) = -06d 44' 27\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peaked\nstructure with a very short duration. The peak count rate\nwas ~6480 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 09:45:57.7 UT, 51.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find an \nX-ray source with an enhanced position: RA, Dec 277.6736, -6.7548 which\nis equivalent to:\n   RA(J2000)  = 18h 30m 41.66s\n   Dec(J2000) = -06d 45' 17.2\"\nwith an uncertainty of 2.1 arcseconds (radius, 90% containment). This\nlocation is 109 arcseconds from the BAT onboard position, within the\nBAT error circle, and consistent with the known location of SGR 1830-0645. \nThis position may be improved as more data are received; the latest position \nis available at https://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (1.11 x\n10^22 cm^-2, Willingale et al. 2013), with an excess column of 1.1\n(+0.80/-0.68) x 10^22 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 55 seconds after the BAT trigger. No credible counterpart has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. Because of the density of catalogued stars, further\nanalysis is required to report an upper limit for any counterpar in the\nsub-image. The 8'x8' region for the list of sources generated on-board covers\n100% of the XRT error circle. Because of the density of catalogued stars,\nfurther analysis is required to report an upper limit for any counterpart in the\nregion. \n\nSwift first triggered on SGR 1830-0645 on 2020 October 10 (GCN Circ. \n28594), although a sub-threshold flare was also detected on October 05\n(GCN 28603).   The source again triggered Swift-BAT on November 05\n(GCN Circ. 28838).",
  "circularId": 28879,
  "createdOn": 1605089086000,
  "email": "klp5@leicester.ac.uk",
  "subject": "Swift Trigger 1005428: Detection of SGR 1830-0645",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>"
}