GCN Circular 17173

J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), T. Sakamoto (AGU) and M. H. Siegel (PSU) report
on behalf of the Swift Team:

At 01:56:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located the source 4U 1700+24 (trigger #621278).  Swift slewed 
immediately to the location.  The BAT on-board calculated location is 
RA, Dec 256.660, +24.020 which is 
   RA(J2000) = 17h 06m 38s
   Dec(J2000) = +24d 01' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for image triggers, there
is no obvious variation in the immediately available BAT lightcurve. 

The XRT began observing the field at 01:58:04.5 UT, 113.5 seconds after
the BAT trigger. XRT found a bright X-ray source located at RA, Dec
256.6412, 23.9734 which is equivalent to:
   RA(J2000)  = +17h 06m 33.89s
   Dec(J2000) = +23d 58' 24.2"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 178 arcseconds from the BAT onboard position, within the
BAT error circle. This position is 9.3 arcseconds from that of a known
X-ray source: 4U 1700+24 (also known as V934 Her). 
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 1.48e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 122 seconds after the BAT trigger. The 2.7'x2.7'
sub-image only shows the bright (V=7.6) known source V934 Her. 

This symbiotic X-ray binary system was previously observed
in outburst by Swift and has been active for roughly the past year
(Krimm et al., ATel #6482).  A BAT lightcurve of its activity
is available at:
http://swift.gsfc.nasa.gov/results/transients/weak/4U1700p24/