[vsnet-grb-info 4110] GRB 061214(?): Swift detection of a possible burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5918
SUBJECT: GRB 061214(?): Swift detection of a possible burst
DATE:    06/12/14 12:39:01 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

S. B. Pandey (UCL-MSSL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
M. M. Chester (PSU), P. A. Evans (U Leicester),
O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB),
V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC),
T. Mineo (INAF-IASFPA), S. R. Oates (UCL-MSSL), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
P. Romano (Univ. Bicocca & INAF-OAB), P. Schady (MSSL-UCL),
R. L. C. Starling (U Leicester) and E. Troja (INAF-IASFPA) report on
behalf of the Swift Team:

At 12:16:53 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 061214 (trigger=250908).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 7.777, -29.640 which is 
   RA(J2000)  =  00h 31m 06s
   Dec(J2000) = -29d 38' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  Given that this is a 4-msec trigger in the high
energy band makes this likely that this trigger is a cosmic ray shower. 
The BAT light curve shows nothing significant, which is also consistant
with a cosmic ray shower.  The peak count rate was ~1000 counts/sec
(15-350 keV), at ~0 sec after the trigger.  Prior to receiving the full
data set in the next downlink, it seems equally likely at this point
that this is cosmic ray shower or a GRB. 

The XRT began taking data at 12:18:15 UT, 82 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in
the image and no prompt position is available. Analysis of promptly
downlinked photon counting data reveals no source in a 163 s exposure. 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 87 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image covers 25% of the BAT error circle. The  3-sigma
upper limit is 19.9 mag. The 8'x8' region for the list of sources
generated on-board covers 100% of the BAT error circle. The list of
sources is typically complete to about 18 mag. No correction has been
made for the expected extinction corresponding to E(B-V) of 0.02.