The X-ray system R Aquarii: A two-sided jet and central source

We report Chandra ACIS-S3 X-ray imaging and spectroscopy of the R Aquarii binary system that show a spatially resolved two-sided jet and an unresolved central source. This is the first published report of such an X-ray jet seen in an evolved similar to2-3 M-circle dot stellar system. At E < 1 keV, the X-ray jet extends to both the northeast (NE) and southwest (SW) relative to the central binary system. At 1 < E < 7.1 keV, R Aqr is a pointlike source centered on the star system. While both 3.5 cm radio continuum emission and X-ray emission appear coincident in projection and have maximum intensities at 7 .5 NE of the central binary system, the next strongest X-ray component is located similar to 30 SW of the central binary system and has no radio continuum counterpart. The X-ray jets are likely shock-heated in the recent past and are not in thermal equilibrium. The strongest SW X-ray jet component may have been shocked recently since there is no relic radio emission as expected from an older shock. At the position of the central binary, we detect X-ray emission below 1.6 keV consistent with blackbody emission at T similar to 2 x 10(6) K. There is also a prominent 6.4 keV feature, a possible fluorescence or collisionally excited Fe K line from an accretion disk or from the wind of the giant star. For this excitation to occur, there must be an unseen hard source of X-rays or particles in the immediate vicinity of the hot star. Such a source would be hidden from view by the surrounding edge-on accretion disk.