GCN Circular 16158

V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), S. T. Holland (STScI),
H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU) and
T. N. Ukwatta (MSU) report on behalf of the Swift Team:

At 21:07:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located an X-ray source (trigger=596958).  Swift slewed immediately to the location. 
The BAT on-board calculated location is 
RA, Dec 202.928, +29.258 which is 
   RA(J2000) = 13h 31m 43s
   Dec(J2000) = +29d 15' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual with an image trigger, 
the BAT light curve shows no significant structure.  This is a 
15-50 keV trigger with a duration of 64 seconds. 

The XRT began observing the field at 21:09:05.1 UT, 117.0 seconds after
the BAT trigger. XRT found a bright X-ray source located at RA, Dec
202.9436, 29.2763 which is equivalent to:
   RA(J2000)  = +13h 31m 46.46s
   Dec(J2000) = +29d 16' 34.7"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 82 arcseconds from the BAT onboard position, within the BAT
error circle. This position is 2.9 arcsec from that of the known flare 
star DG CVn, and 1.1 arcseconds from that of a known X-ray source, 
3XMM J133146.5+291635 in the XMM-NEWTON XMMSSC catalogue. 
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 4.10e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 125 seconds after the BAT trigger. UVOT sees a very bright saturated
source near the XRT position. Because of coincidence loss, it is difficult to
accurately determine the position or count rate.