{
  "bibcode": "2013GCN.14396....1B",
  "body": "W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU),\nS. T. Holland (STScI), J. A. Kennea (PSU),\nH. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC),\nF. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 17:24:37 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a possible trigger from the RS CVn flare star HR 5110 \n(trigger=553930).  Swift slewed immediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 203.650, +37.239 which is \n   RA(J2000) = 13h 34m 36s\n   Dec(J2000) = +37d 14' 20\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is usual with an image trigger, the BAT \nlight curve does not show any significant features. \n\nThe XRT began observing the field at 17:26:43.4 UT, 125.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find an X-ray source\nlocated at RA, Dec 203.70026, 37.18112 which is equivalent to:\n   RA(J2000)  = 13h 34m 48.06s\n   Dec(J2000) = +37d 10' 52.0\"\nwith an uncertainty of 4.7 arcseconds (radius, 90% containment). This\nlocation is 253 arcseconds from the BAT onboard position, outside 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. This position is 5.5 arcseconds from that\nof HR 5110. We note that the XRT data are highly affected by optical loading\nfrom the star, and therefore we cannot determine at this time if there \nis any enhanced X-ray emission detected from this source. \n\nUVOT took a finding chart exposure of 250 seconds with the UVW2 filter starting\n123 seconds after the BAT trigger. No new source is detected in the initial\ndata products. Analysis of the UVOT data is complicated by the presence of the\n5th magnitude star HR 5110. \n\nSince this was a low-significance (6.0 sigma) image trigger, it is not\npossible to tell from the rapidly available BAT data whether or not\nthis is a real event.  Further information will be available once the\nfull BAT data is available.",
  "circularId": 14396,
  "createdOn": 1366394084000,
  "email": "krimm@milkyway.gsfc.nasa.gov",
  "subject": "Trigger 553930: Swift detection of a possible flare from HR 5110",
  "submitter": "Hans Krimm at NASA-GSFC  <krimm@milkyway.gsfc.nasa.gov>"
}