{
  "bibcode": "2019GCN.23849....1B",
  "body": "S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB),\nP. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), N. J. Klingler (PSU),\nN. P. M. Kuin (UCL-MSSL), D. M. Palmer (LANL) and A. Tohuvavohu (PSU)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 21:18:17 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated SWIFT J1728.9-3613 (trigger=887541).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 262.301, -36.267 which is \n   RA(J2000) = 17h 29m 12s\n   Dec(J2000) = -36d 16' 01\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty). As is usual with an image trigger, the available\nBAT light curve shows no significant structure. \n\nThe XRT began observing the field at 21:28:10.1 UT, 592.5 seconds after\nthe BAT trigger. XRT found a bright X-ray source located at RA, Dec\n262.2442, -36.2421 which is equivalent to:\n   RA(J2000)  = 17h 28m 58.61s\n   Dec(J2000) = -36d 14' 31.6\"\nwith an uncertainty of 4.7 arcseconds (radius, 90% containment). This\nlocation is 187 arcseconds from the BAT onboard position, outside the\nBAT error circle. This position is consistent with the position of Swift J1728.9-3613 (J. Kennea ATel #12445). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 602 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 100% of\nthe XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nXRT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the large, but uncertain, extinction expected.",
  "circularId": 23849,
  "createdOn": 1549230127000,
  "email": "aaronb@swift.psu.edu",
  "subject": "Swift Trigger 887541: Swift detection of Swift J1728.9-3613",
  "submitter": "Aaron Tohuvavohu at PSU/Swift  <aaronb@swift.psu.edu>"
}