[vsnet-grb-info 20285] GRB 180205A: Swift detection of a burst with a bright optical counterpart

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22381
SUBJECT: GRB 180205A: Swift detection of a burst with a bright optical counterpart
DATE:    18/02/05 04:45:57 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

P. A. Evans (U Leicester), J. A. Kennea (PSU),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:

BAT has detected GRB 180205A (trigger #808625), leading to a slew
and follow-up observations by Swift.  However, due to missing 
telemetry packets, no further BAT information is available at 
this time. 

The XRT began observing the field at 04:28:23.6 UT. XRT found 
a bright, uncatalogued X-ray source
located at RA, Dec 126.8206, 11.5419 which is equivalent to:
   RA(J2000)  = +08h 27m 16.94s
   Dec(J2000) = +11d 32' 30.8"
with an uncertainty of 5.6 arcseconds (radius, 90% containment). No
event data are yet available to determine the column density using
X-ray spectroscopy. 

The initial flux in the 2.5 s image was 9.50e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
at 04:28:30.79 UT. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	08:27:16.73 = 126.81970
  DEC(J2000) = +11:32:30.7  =  11.54185
with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.65 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03. 

Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)