Swift/XRT monitoring of the latest outburst from XMMUJ174716.1-281048: the source is still active
ATel #1496; L. Sidoli (INAF-IASF Milano), P. Romano (INAF-IASF Palermo), M. Del Santo (INAF-IASF Roma), R. Wijnands (UvA) and N. Degenaar (UvA)
on 29 Apr 2008; 15:04 UT
Credential Certification: Lara Sidoli (email@example.com)
Subjects: X-ray, Transient
The Very Faint X-ray Transient (VFXT) XMMUJ174716.1-281048
(ATel #147 and Sidoli et al., 2006, A&A 456, 287) is being observed with
Swift/XRT since May 2007 (Degenaar et al. 2007, ATel #1136),
in order to monitor the level of activity during the latest outburst,
which started in 2003 (Del Santo et al., 2007, A&A 468, L17; ATel #1078, #1136).
XMMUJ174716.1-281048 is indeed the first VFXT with a ``quasi persistent" behaviour.
The last previous Swift/XRT observation (Sidoli et al., 2007, ATel
#1174) detected the source at a rate of (3.56+/-0.71)E-02 counts/s in July
2007 and at (1.50+/-0.35)E-02 counts/s in Aug 2007 (0.2-10 keV).
Swift/XRT observed XMMUJ174716.1-281048 on 28 Apr 2008.
The source is still active, with a 0.2-10 keV count rate of
(2.89+/-0.48)E-02 count/s, which translates into a 0.2-10 keV flux,
corrected for the absorption, of ~3.3E-12 erg/cm2/s (assuming a power
law model with a photon index of 2.25, absorbed by a column density of
The source activity is not decreasing, with a duration of the latest
outburst of probably more than five years, confirming what suggested
by Del Santo et al. (2007, A&A 468, L17), that the source is a
"quasi persistent" transient.
We will continue the monitoring of the source flux in the next months with
We would like to thank the Swift Team for making these observations
possible, in particular N. Gehrels, the duty scientists as well as the