{
  "bibcode": "2017GCN.20540....1C",
  "body": "J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),\nS. B. Cenko (GSFC), A. Cholden-Brown (PSU), A. D'Ai (INAF-IASFPA),\nV. D'Elia (ASDC), P.A. Evans (U Leicester), J. A. Kennea (PSU),\nF. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)\nreport on behalf of the Swift Team:\n\nAt 15:13:28 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 170127B (trigger=735331).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 19.944, -30.338, which is \n   RA(J2000)  =  01h 19m 47s\n   Dec(J2000) = -30d 20' 14\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single spike\nstructure with a duration of about 0.2 sec.  The peak count rate\nwas ~8000 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 15:14:43.3 UT, 74.7 seconds after\nthe BAT trigger. Using promptly downlinked data we find an uncatalogued\nX-ray source with an enhanced position: RA, Dec 19.9766, -30.3588 which\nis equivalent to:\n   RA(J2000)  = 01h 19m 54.37s\n   Dec(J2000) = -30d 21' 31.6\"\nwith an uncertainty of 2.9 arcseconds (radius, 90% containment). This\nlocation is 125 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.  We cannot determine whether the source is\nfading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density consistent with the Galactic value of 2.01\nx 10^20 cm^-2 (Willingale et al. 2013). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 113 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 none of\nthe XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.02. \n\nBurst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.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": 20540,
  "createdOn": 1485530704000,
  "email": "kennea@swift.psu.edu",
  "subject": "GRB 170127B: Swift detection of a short burst",
  "submitter": "Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>",
  "eventId": "GRB 170127B"
}