{
  "bibcode": "2011GCN.11807....1M",
  "body": "A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), P. D'Avanzo (INAF-OAB),\nJ. M. Gelbord (PSU), C. Gronwall (PSU),\nS. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (UCL-MSSL),\nR. Margutti (INAF-OAB), C. B. Markwardt (NASA/GSFC),\nF. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),\nB. Sbarufatti (INAF-OAB/IASFPA) and M. H. Siegel (PSU) report on\nbehalf of the Swift Team:\n\nAt 02:16:41 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 110319A (trigger=449578).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is RA, Dec 356.401, -66.017 which is \n   RA(J2000) = 23h 45m 36s\n   Dec(J2000) = -66d 01' 01\"\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 ~30 sec.  The peak count rate\nwas ~3800 counts/sec (15-350 keV), at ~5 sec after the trigger. \n\nThe XRT began observing the field at 02:17:37.5 UT, 55.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n356.5017, -66.0114 which is equivalent to:\n   RA(J2000)  = 23h 46m 0.40s\n   Dec(J2000) = -66d 00' 40.9\"\nwith an uncertainty of 2.3 arcseconds (radius, 90% containment). This\nlocation is 148 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 consistent with the Galactic value of 2.62\nx 10^20 cm^-2 (Kalberla et al. 2005). \n\nThe initial flux in the 2.5 s image was 1.10e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\n     UVOT took a finding chart exposure of 150 seconds with the White\nfilter starting 66 seconds after the BAT trigger.  No credible\nafterglow candidate has been found in the initial data products.  The\n2.7' x 2.7' sub-image covers 100% of the XRT error circle.  The typical\n3-sigma upper limit has been about 19.6 mag. No correction has been\nmade for the expected extinction corresponding to E(B-V) of 0.03. \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": 11807,
  "createdOn": 1300501897000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 110319A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 110319A"
}