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 stellar system comprised of ~2-3 M (also see Kellogg et al 2000). At E < 1 keV, the x-ray jet extends both to the northeast and southwest relative to the central binary system. At 1 < E < 7.1 keV, R Aqr is a point-like 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 ~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 ~ 2 × 10 6 K. There is also a prominent 6.4 keV feature, a possible fluorescence or collisionally excited Fe Kα 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.

The jet feedback mechanism (JFM) in stars, galaxies and clusters

“…X-ray observations seem also to support the presence of jet-inflated bubbles and of jets Sahai et al 2003), similar to X-ray jets in symbiotic systems (e.g., Kellogg et al 2001;Galloway & Sokoloski 2004). …”

Why a Single‐Star Model Cannot Explain the Bipolar Nebula of η Carinae

“…In a series of papers, I argue that this suggests that bubble pairs in PNs (Soker 2003a(Soker , 2003b(Soker , 2004a and symbiotic nebulae (Soker 2004b) are also formed by such jets (note that not all PNs are shaped by jets). In particular, there are more and more observations showing and hinting at the presence of jets in symbiotic systems (e.g., Kellogg et al 2001;Brocksopp et al 2004), in PNs, and in PN progenitors (e.g., Imai et al 2002;Hirano et al 2004;Sahai et al 2003).…”

Detection of X-rays from the jet-driving symbiotic star MWC 560

“…It shows a rich morphology with hints of pulsed ejection. Furthermore, R Aqr is the first jet in a symbiotic system that was detected in X-rays (Viotti et al 1987;Hünsch et al 1998;Kellogg et al 2001). The spectra of the jets are consistent with a soft component with kT ∼ 0.25 keV.…”