{
  "bibcode": "2011GCN.11790....1M",
  "body": "A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC),\nP. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU),\nC. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC),\nE. A. Hoversten (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),\nV. Mangano (INAF-IASFPA), R. Margutti (INAF-OAB),\nC. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),\nC. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA) and\nM. H. Siegel (PSU) report on behalf of the Swift Team:\n\nAt 23:57:04 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 110315A (trigger=449399).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 279.191, +17.532 which is \n   RA(J2000)  =  18h 36m 46s\n   Dec(J2000) = +17d 31' 56\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows 3 or 4 peaks\nwith a total duration of about 20 sec.  The peak count rate\nwas ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger. \n\nThe XRT began observing the field at 23:58:49.1 UT, 104.6 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 279.1928, +17.5388 which is equivalent to:\n   RA(J2000)  = 18h 36m 46.27s\n   Dec(J2000) = +17d 32' 19.6\"\nwith an uncertainty of 5.8 arcseconds (radius, 90% containment). This\nlocation is 25 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 112 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 coverage of the XRT error circle by the 8'x8' region for the list of\nsources generated on-board is uncertain because the large number of sources\nfilled the available telemetry. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.25. \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": 11790,
  "createdOn": 1300234162000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 110315A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 110315A"
}