ChandraObservations of the Bursting X‐Ray Transient SAX J1747.0−2853 during Low‐Level Accretion Activity

We present Chandra/ACIS observations of the bursting X-ray transient SAXJ1747.0-2853 performed on 18 July 2001. We detected a bright source at theposition of R.A = 17^h 47^m 02.60^s and Dec. = -28 52' 58.9'' (J2000.0; with a1 sigma error of ~0.7 arcseconds), consistent with the BeppoSAX and ASCApositions of SAX J1747.0-2853 and with the Ariel V position of the transient GX+0.2,-0.2, which was active during the 1970's. The 0.5-10 keV luminosity of thesource during our observations was ~3 x 10^{35} erg/s (assuming a distance of 9kpc) demonstrating that the source was in a low-level accretion state. We alsoreport on the long-term light curve of the source as observed with the all skymonitor aboard the Rossi X-ray Timing Explorer. After the initial 1998outburst, two more outbursts (in 2000 and 2001) were detected with peakluminosities about two orders of magnitude larger than our Chandra luminosity.Our Chandra observation falls in-between those two outbursts, making theoutburst history for SAX J1747.0-2853 complex. Those bright 2000 and 2001outbursts combined with the likely extended period of low level activityin-between those outbursts strongly suggest that the classification of SAXJ1747.0-2853 as a faint X-ray transient was premature. It might be possiblethat the other faint X-ray transients also can exhibit bright, extendedoutbursts which would eliminate the need for a separate sub-class of X-raytransients. We discuss our results also in the context of the behavior of X-raybinaries accreting at low levels with luminosities around 10^{35} erg/s, apoorly studied accretion rate regime.Comment: Accepte for publication in ApJ, 11 July 200