{
  "bibcode": "2013GCN.15516....1M",
  "body": "C. B. Markwardt (NASA/GSFC), S. D. Barthelmy (GSFC),\nS. B. Cenko (GSFC), V. D'Elia (ASDC), D. Malesani (DARK/NBI),\nF. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),\nD. M. Palmer (LANL) and P. Romano (INAF-IASFPA) report on behalf of\nthe Swift Team:\n\nAt 10:11:35 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 131127A (trigger=579571).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 332.751, +36.590 which is \n   RA(J2000)  =  22h 11m 00s\n   Dec(J2000) = +36d 35' 24\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows several overlapping\npeaks with a duration of about 50 sec.  The peak count rate\nwas ~1600 counts/sec (15-350 keV), at 0 sec after the trigger. \n\nThe XRT began observing the field at 10:13:09.3 UT, 93.8 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source with an enhanced position: RA, Dec\n332.7293, 36.6098 which is equivalent to:\n   RA(J2000)  = 22h 10m 55.03s\n   Dec(J2000) = +36d 36' 35.2\"\nwith an uncertainty of 2.1 arcseconds (radius, 90% containment). This\nlocation is 94 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 consistent with the Galactic value of 1.15\nx 10^21 cm^-2 (Kalberla et al. 2005). \n\nThe initial flux in the 2.5 s image was 1.33e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 102 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. \nData from the list of sources generated on-board are not available at this\ntime. No correction has been made for the expected extinction corresponding to\nE(B-V) of 0.14. \n\nBurst Advocate for this burst is C. B. Markwardt (Craig.Markwardt 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": 15516,
  "createdOn": 1385548421000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 131127A: Swift detection of a burst",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 131127A"
}