{
  "bibcode": "2011GCN.12209....1O",
  "body": "S. R. Oates (UCL-MSSL), W. H. Baumgartner (GSFC/UMBC),\nA. P. Beardmore (U Leicester), S. Campana (INAF-OAB),\nN. Gehrels (NASA/GSFC), E. A. Hoversten (PSU),\nH. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),\nF. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),\nC. J. Mountford (U Leicester), K. L. Page (U Leicester),\nD. M. Palmer (LANL), P. Romano (INAF-IASFPA), C. J. Saxton (UCL-MSSL),\nB. Sbarufatti (INAF-OAB/IASFPA) and G. Tagliaferri (INAF-OAB) report\non behalf of the Swift Team:\n\nAt 11:19:15 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated on a short burst from the AXP 4U 0142+61 (trigger=458345).  \nSwift slewed immediately to the source location. \nThe BAT on-board calculated location is \nRA, Dec 26.598, +61.729 which is \n   RA(J2000) = 01h 46m 24s\n   Dec(J2000) = +61d 43' 43\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peaked\nstructure with a duration of about 0.1 sec.  The peak count rate\nwas ~3500 counts/sec (15-350 keV), at ~0.1 sec after the trigger. \n\nThe XRT began observing the field at 11:20:38.1 UT, 82.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright\nsource with an enhanced position: RA,Dec = 26.5937, 61.7510 (degrees) \nwhich is equivalent to:\n\nRA  (J2000.0) = 01 46 22.48\nDEC (J2000.0) = +61 45 03.6\n\nwith an uncertainty of 2.2 arcsec (radius, 90% containment). \nThis is consistent with the position of 4U 0142+61. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 93 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. \n\nSwift has been regularly monitoring this source 4U 0142+61 as\npart of program of regular monitoring of AXPs (PI: V. Kaspi). \nThis AXP has previously been seen to emit SGR-like bursts\n(e.g. ATEL #794, Kaspi et al., 2006)\n\nBurst Advocate for this burst is S. R. Oates (sro AT mssl.ucl.ac.uk). \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": 12209,
  "createdOn": 1311940353000,
  "email": "palmer@lanl.gov",
  "subject": "Swift detection of a SGR-like burst from the AXP 4U 0142+61",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>"
}