{
  "bibcode": "2009GCN..9545....1C",
  "body": "P.A. Curran (MSSL-UCL), S. D. Barthelmy (GSFC),\nA. P. Beardmore (U Leicester), D. N. Burrows (PSU),\nN. Gehrels (NASA/GSFC), J. A. Kennea (PSU),\nC. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),\nD. M. Palmer (LANL), A. Rowlinson (U Leicester),\nT. Sakamoto (NASA/UMBC), P. Schady (MSSL-UCL), M. C. Stroh (PSU) and\nH. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:\n\nAt 22:07:25 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 090621B (trigger=355359).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 313.432, +69.013 which is \n   RA(J2000)  =  20h 53m 44s\n   Dec(J2000) = +69d 00' 48\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single spike\nwith a duration less than 128 millisec.  The peak count rate\nwas ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at  22:08:36UT, 70.7 s after the BAT trigger. \nIn promptly downlinked data, XRT found a faint uncatalogued source at RA, Dec \n(J2000) = 313.4700,   69.0282, which is\nRA = 20h 53m 52.8s\nDec = +69d 01' 41.5\"\nwith an uncertainty of 8.0 arcseconds (radius, 90% containment). This\nlocation is 73 arcseconds from the BAT onboard position, within the BAT\nerror circle. \n\nUVOT took a finding chart exposure of nominal 150 seconds with the\nWhite filter  starting 76 seconds after the BAT trigger. No credible\nafterglow candidate has  been found in the initial data products at\nthe XRT position. Data from the 2.7'x2.7' sub-image are not available\nat this time. The 8'x8' region for the list of sources generated\non-board covers 100% of the BAT error circle. The list of sources is\ntypically complete to about 18 mag. No correction has been made for\nthe expected extinction corresponding to E(B-V) of 0.43 (Schlegel et\nal. 1998). \n\nBurst Advocate for this burst is P.A. Curran (pac 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": 9545,
  "createdOn": 1245623915000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090621B: Swift detection of a short hard burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090621B"
}