The X-Ray System R Aquarii: A Two-sided Jet and Central Source

Abstract

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 ∼2–3 M, stellar system. At keV, the X-ray jet extends to both the northeast E ! 1 (NE) and southwest (SW) relative to the central binary system. At keV, R Aqr is a pointlike source 1 ! E ! 7.1 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 ∼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 K. There is also a prominent 6.4 keV feature, a possible fluorescence or collisionally 6 T ∼ 2 # 10 excited Fe Ka 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. Subject headings: binaries: symbiotic — circumstellar matter — radio continuum: stars — stars: individual (R Aquarii) — stars: winds, outflows — white dwarfs — X-rays: general