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ATEL # 892; R. Wijnands (UvA), E. Kuulkers(ESA/ESAC), M. Muno (Caltech), E. Cackett (U. Michigan), J. in 't Zand (SRON-Utrecht), T. Maccarone, R. Fender (U. Southampton), J. Grindlay (CfA), J. Homan (MIT), M. Rupen (NRAO), R. Cornelisse (IAC), J. Miller-Jones, M. van der Klis (UvA), C. Markwardt (U. Maryland, NASA/GSFC), D. Wang (U. Massachusetts)
on 21 Sep 2006; 10:58 UT
Password Certification: Rudy Wijnands (firstname.lastname@example.org)
Subjects: X-ray, Binaries, Black Holes, Neutron Stars, Transients
On 8-9 September 2006, a series of 7 XMM-Newton observations were performed as part of our XMM-Newton/Chandra monitoring campaign of the 1.7 square degree region around Sgr A* (Wijnands et al. 2006, A&A, 449, 1117). Two X-ray transients were active during our observations.
A very-faint transient is active with an 2-10 keV X-ray luminosity of approximately 2E34 erg/s (absorption corrected and for an assumed distance of 8 kpc). The source position is R.A.= 17h45m35.63s and Decl.=-29d01m24s (J2000, with an error of approximately 4 arcseconds). This position is consistent with that of the very-faint X-ray transient CXOGC J174535.5-290124 (Muno et al. 2005, ApJ, 622, L113) and likely we have detected renewed activity of this source. We note that this source is located close (11.5") to the transient source Swift J174535.5-290135.6 (ATEL #753) which was active earlier this year but the position of this source is inconsistent with that of the detected source. We do not detect this Swift transient during our observations.
In addition we detect continued activity of the neutron-star X-ray transient SAX J1747.0-2853 at a 2-10 keV X-ray luminosity of approximately 9E35 erg/s (absorption corrected and for a distance of 8 kpc). Likely this source has been in outburst since October 2005 (ATEL #637) since it has been reported to be active on several occasions after its initial detection (ATELs #638, #641, #642, #734). Although we cannot exclude that the source went into quiescence in-between observations, such prolonged outbursts are not uncommon for this source.