{
  "bibcode": "2015GCN.17507....1B",
  "body": "S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),\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 04:53:25 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated 4U 0142+61 (trigger=632888).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 26.571, +61.768, which is \n   RA(J2000)  =  01h 46m 17s\n   Dec(J2000) = +61d 46' 04\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows 4 short spikes\n(<~0.1 s) over a total duration of about 20 sec.  The peak count rate\nwas ~8000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 04:54:43.2 UT, 78.3 seconds after\nthe BAT trigger. XRT found a bright X-ray source located at RA, Dec\n26.5966, 61.7519 which is equivalent to:\n   RA(J2000)  = +01h 46m 23.18s\n   Dec(J2000) = +61d 45' 06.8\"\nwith an uncertainty of 5.2 arcseconds (radius, 90% containment). This\nlocation is 72 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position is 7.3 arcseconds from a known X-ray\nsource: 1SXPS J014622.3+614502. This source is in the Swift XRT 1SXPS\ncatalogue with a mean 0.3-10 keV count-rate of 4.610 +/- 0.021 ct/sec;\nsee http://www.swift.ac.uk/1SXPS/1SXPSJ014622.3%2B614502 for details of\nthese previous observations. No event data are yet available to\ndetermine the column density using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 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. 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. \n\nThis source has been previously detected by BAT on timescales of both\nminutes and milliseconds, most recently on February 19 of this year.",
  "circularId": 17507,
  "createdOn": 1425100266000,
  "email": "palmer@lanl.gov",
  "subject": "Trigger 632888: Swift detection of the magnetar 4U 0142+61",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>"
}