{
  "bibcode": "2012GCN.13831....1D",
  "body": "V. D'Elia (ASDC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),\nN. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU),\nC. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),\nK. L. Page (U Leicester), B. Sbarufatti (INAF-OAB/PSU),\nM. H. Siegel (PSU), E. Sonbas (NASA/GSFC/Adiyaman Univ.) and\nE. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:\n\nAt 18:23:02 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated trigger 535026.  Swift slewed immediately to the location.\nThe BAT on-board calculated location is\nRA, Dec 276.033, -5.667 which is\n   RA(J2000) = 18h 24m 08s\n   Dec(J2000) = -05d 40' 00\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including\nsystematic uncertainty).  The BAT light curve showed a weak multi-peaked\nstructure with a duration of about 25 sec.  The peak count rate\nwas ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger.\n\nThe XRT began observing the field at 18:25:03.7 UT, 121.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n276.0325, -5.6654 which is equivalent to:\n   RA(J2000)  = 18h 24m 07.80s\n   Dec(J2000) = -05d 39' 55.5\"\nwith an uncertainty of 2.7 arcseconds (radius, 90% containment). This\nlocation is 6.0 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 gives a column density in excess of the Galactic value (4.53 x\n10^21 cm^-2, Kalberla et al. 2005), with an excess column of 5.5\n(+4.26/-3.49) x 10^21 cm^-2 (90% confidence).\n\nThe initial flux in the 2.5 s image was 5.49e-10 erg cm^-2 s^-1 (0.2-10\nkeV).\n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n287 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers 100% of the\nXRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The\n8'x8' region for the list of sources generated on-board covers 100% of the XRT\nerror circle. The list of sources is typically complete to about 18.0 mag. No\ncorrection has been made for the large, but uncertain extinction expected.\n\nThe classification of this trigger is uncertain, but it's quite\nlikely that it is a galactic transient.  The duration (~20 sec) and\nlow energy emission (<25 keV) are consistent with it being a\nthermonuclear X-ray burst from a neutron star.  The location is 3.5\ndegrees from the galactic plane.\n\nBurst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it).\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": 13831,
  "createdOn": 1349117645000,
  "email": "kennea@swift.psu.edu",
  "subject": "Swift Trigger 535026: Galactic Transient or possible GRB",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>"
}