V. D'Elia (ASDC), M. De Pasquale (INAF-IASFPA),
P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA),
A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), T. Sakamoto (AGU)
and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:
At 09:08:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a source (trigger=625898). Swift slewed immediately to this location.
The BAT on-board calculated location is
RA, Dec 348.364, +2.679 which is
RA(J2000) = 23h 13m 27s
Dec(J2000) = +02d 40' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). This is a 320-s image trigger.
As is usual with an image trigger, the
rapidly available BAT light curve shows no significant features.
The XRT began observing the field at 09:15:03.4 UT, 380.5 seconds after
the BAT trigger. XRT found a bright X-ray source located at RA, Dec
348.3493, 2.6753 which is equivalent to:
RA(J2000) = +23h 13m 23.83s
Dec(J2000) = +02d 40' 31.1"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 54 arcseconds from the BAT onboard position, within the BAT
error circle. This position is 4.1 arcseconds from that of a known
X-ray source: XMMSL1 J231323.5+024033 in the XMM-NEWTON XMMSLEWCLN
catalogue, also known as SZ Psc, a RS CVn variable type. No event
data are yet available to determine the column density using
The initial flux in the 2.5 s image was 3.72e-09 erg cm^-2 s^-1 (0.2-10
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 389 seconds after the BAT trigger. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The source appears saturated.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT 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