F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
G. Cusumano (INAF-IASFPA), V. Mangano (INAF-IASFPA),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
C. Pagani (PSU), D. M. Palmer (LANL),
P. Romano (Univ. Bicocca & INAF-OAB), B. Sbarufatti (INAF-IASFPA),
D. E. Vanden Berk (PSU) and H. Ziaeepour (UCL-MSSL) report on behalf
of the Swift Team:
At 08:49:18 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger=280447)
and located a probable Galactic transient. Due to the Earth limb constraint,
the Swift slew to the target was delayed by 9 minutes.
The BAT on-board calculated location is
RA, Dec 301.271, +31.484 which is
RA(J2000) = 20h 05m 05s
Dec(J2000) = +31d 29' 02"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is usual for 64 second image triggers,
the raw BAT lightcurve available via TDRSS does not show any
The XRT began observing the field at 09:00:38 UT, 680 seconds after the
BAT trigger. XRT found a bright uncatalogued X-ray source
located at RA, Dec 301.3168, +31.3876 which is
RA(J2000) = 20h 05m 16.0s
Dec(J2000) = 31d 23' 15.3"
with an uncertainty of 4.7 arcseconds (radius, 90% containment).
This location is 374 arcseconds from the BAT on-board position,
outside the BAT error circle. The initial flux in the 2.5s image
was 8.8e-09 erg/cm2/s (0.2-10 keV).
There is no UVOT information for this burst. This trigger is
distinct and separate from the trigger 280450. We will have a separate
circular on that second trigger shortly.
This location is on the Galactic plane (lat=-0.2deg), the XRT intensity
is much brighter than would be expected for a GRB at T+10
minutes and is highly-absorbed non-power-law spectrum.
Therefore this source is probably a Galactic transient.