{
  "bibcode": "2013GCN.14527....1T",
  "body": "E. Troja (NASA/GSFC/UMCP), A. A. Breeveld (UCL-MSSL),\nP. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC),\nS. T. Holland (STScI), H. A. Krimm (CRESST/GSFC/USRA),\nC. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),\nA. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),\nM. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. C. Stroh (PSU),\nC. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the\nSwift Team:\n\nAt 17:50:30 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 130502A (trigger=554996).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 138.578, -0.143 which is \n   RA(J2000) = 09h 14m 19s\n   Dec(J2000) = -00d 08' 35\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a double-peaked\nstructure with a duration of about 5 sec.  The rapidly available light\ncurve also shows a peak in the lowest energy at T+10 sec, but it is\nnot clear at this time whether or not the second peak is real. The \npeak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after \nthe trigger. \n\nThe XRT began observing the field at 17:52:01.8 UT, 91.4 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 138.5690, -0.1232 which\nis equivalent to:\n   RA(J2000)  = 09h 14m 16.56s\n   Dec(J2000) = -00d 07' 23.7\"\nwith an uncertainty of 2.2 arcseconds (radius, 90% containment). This\nlocation is 78 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (2.49 x\n10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.5\n(+1.77/-1.57) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 95 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 expected extinction corresponding to E(B-V) of\n0.03. \n\nBurst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov). \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": 14527,
  "createdOn": 1367518077000,
  "email": "kennea@swift.psu.edu",
  "subject": "GRB 130502A: Swift detection of a burst",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>",
  "eventId": "GRB 130502A"
}