{
  "bibcode": "2013GCN.14735....1M",
  "body": "A. Melandri (INAF-OAB), W. H. Baumgartner (GSFC/UMBC),\nD. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),\nN. Gehrels (NASA/GSFC), C. Gronwall (PSU), K. L. Page (U Leicester),\nD. M. Palmer (LANL), R. L. C. Starling (U Leicester) and\nT. N. Ukwatta (MSU) report on behalf of the Swift Team:\n\nAt 15:49:14 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 130603B (trigger=557310).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 172.209, +17.045 which is \n   RA(J2000) = 11h 28m 50s\n   Dec(J2000) = +17d 02' 42\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single spike\nstructure with a duration of about 0.4 sec.  The peak count rate\nwas 60000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 15:50:12.8 UT, 59.0 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 172.2006, 17.0719 which\nis equivalent to:\n   RA(J2000)  = 11h 28m 48.16s\n   Dec(J2000) = +17d 04' 18.8\"\nwith an uncertainty of 2.7 arcseconds (radius, 90% containment). This\nlocation is 101 arcseconds from the BAT onboard position, within the\nBAT error circle. This position may be improved as more data are\nreceived; the latest position is available at\nhttp://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 (1.93 x\n10^20 cm^-2, Kalberla et al. 2005), with an excess column of 6.8\n(+4.00/-3.31) x 10^21 cm^-2 (90% confidence). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 62 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 25% of\nthe BAT 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\nBAT 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\n0.02. \n\nThe Swift star trackers were not locked at the time of the\nburst, so there may be some additional error in the position. \nHowever the spike in the rates and the image detection is\nunambiguously real. \n\nWe note that this bright short hard GRB is near (12 arcminutes) \nthe location of the nearby galaxy NGC 3691.  At z=0.003566, this\ncorresponds to a nominal projected distance of about 50 kpc. \n\nBurst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). \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": 14735,
  "createdOn": 1370276125000,
  "email": "palmer@lanl.gov",
  "subject": "GRB 130603B: Swift detection of a bright short burst",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "eventId": "GRB 130603B"
}