X-Ray Isophotes in a Rapidly Rotating Elliptical Galaxy: Evidence of Inflowing Gas

We describe two-dimensional gasdynamical computations of the X-ray emitting gas in the rotating elliptical galaxy 4649 that indicate an inflow of ∼1 M yr−1 at every radius. Such a large instantaneous inflow cannot have over a Hubble time. The central constant-entropy temperature peak recently observed in the innermost 150 pc is explained by compressive heating as gas flows toward the central massive black hole. Since the cooling of this gas is only a few million years, NGC 4649 provides the most acutely concentrated known example of cooling flow problem in which the time-integrated apparent mass that has flowed into the galactic core exceeds total mass observed there. This paradox can be resolved by intermittent outflows of energy or mass driven by energy released near the black hole. Inflowing gas is also required at intermediate kpc radii to explain ellipticity of X-ray isophotes due to spin-up by mass ejected by stars that rotate with the galaxy and to explain density and temperature profiles. We provide evidence that many luminous elliptical galaxies undergo similar spin-up. A small turbulent viscosity is required in NGC 4649 to avoid forming large X-ray luminous disks are not observed, but the turbulent pressure is small and does not interfere with mass determinations that assume equilibrium.