{
  "bibcode": "2015GCN.17514....1B",
  "body": "S. D. Barthelmy (GSFC), M. M. Chester (PSU),\nM. De Pasquale (INAF-IASFPA), N. Gehrels (NASA/GSFC),\nA. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),\nA. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU)\nreport on behalf of the Swift Team:\n\nAt 17:58:50 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a likely noise event (trigger=633173).  Swift slewed immediately\nto the location. The BAT on-board calculated location is \nRA, Dec 139.480, -22.437, which is \n   RA(J2000)  =  09h 17m 55s\n   Dec(J2000) = -22d 26' 13\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is typical for image triggers, nothing shows up\nin the real-time TDRSS light curve. \n\nNo XRT counterpart was detected in 980 s of promptly downlinked data. \n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n341 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 21% of the\nBAT 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 BAT\nerror circle. The list of sources is typically complete to about 18.0 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.10. \n\nThis event alerted as part of a program to follow up low-significance\npossible detections in the direction of nearby galaxies. \nDue to the marginal significance of the detection (6.16 sigma)\nthe distance of the event from the putative host galaxy (5 arcminutes,\nabout twice the galaxy's nominal radius) and the lack of a detection\nby the XRT and UVOT, we believe that this is not an astrophysical\ndetection.",
  "circularId": 17514,
  "createdOn": 1425234304000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 633173 is probably not an astrophysical source",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>"
}