Swift/XRT monitoring of the long outburst of the Very Faint X-ray Transient XMMU J174716.1-281048

ATel #2624; Melania Del Santo (INAF/IASF-Roma), Patrizia Romano (INAF/IASF-Palermo), Lara Sidoli (INAF/IASF-Milano)
on 18 May 2010; 13:25 UT
Credential Certification: Melania Del Santo (melania.delsanto@iasf-roma.inaf.it)

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The Very Faint X-ray Transient (VFXT) XMMU J174716.1-281048, discovered in 2003 by XMM-Newton (ATel #147 and Sidoli et al., 2006, A&A 456, 287), is a type I burster (ATel #970; #972; Del Santo et al., 2007, A&A 468, L17) lying in the Galactic Centre region (ATel #1207). XMMU J174716.1-281048 is the first source classified as ``quasi persistent" VFXT, because it is in outburst since 2003 (Del Santo et al., 2007, A&A 468, L17; ATel #1078). The level of its X-ray emission has been regularly monitored by Swift since May 2007 (ATel #1078, #1174, #1496, #2050).

A new ToO with Swift/XRT was performed on 2010 May 13 07:28:35 to 10:51:56 (1 ks net exposure), and on May 17 07:38:46 to 14:10:48 (3.7 ks net exposure). The source was found still in outburst with a mean 0.2-10 keV count rate of (2.3+/-0.4)E-02 counts/s. The XRT spectrum can be fitted with an absorbed power law with a photon index of 2.3 (-1.3, +1.5) and a column density, Nh, of 8 (-4, +6) E22 cm^-2 (cstat=61.2, dof=62). The 2-10 keV unabsorbed flux of 4E-12 erg/cm2/s translates into a luminosity of 3E34 erg/s (at 8 kpc).

The long-term light curve of XMMU J174716.1-281048 can be found at http://www.ifc.inaf.it/~romano/ATels/XMMUJ174716.1_281048_xrt.html

We would like to thank the Swift Team for making these observations possible, in particular N. Gehrels, the duty scientists as well as the science planners.