ChandraImaging of the X‐Ray Core of the Virgo Cluster

We report sub-arcsecond X-ray imaging spectroscopy of M87 and the core of theVirgo cluster with the Chandra X-ray Observatory. The X-ray morphology showsstructure on arcsecond (~100 pc) to ten arcminute (~50 kpc) scales, the mostprominent feature being an "arc" running from the east, across the centralregion of M87 and off to the southwest. A ridge in the radio map, ending in an"ear"-shaped structure, follows the arc to the east. Depressions in the X-raysurface brightness correspond to the inner radio lobes and there is no evidenceof shock-heated gas surrounding them. There are also at least two approximatelycircular (centered near the nucleus) "edges" in the X-ray brightnessdistribution, the radii of which are slightly larger than the nuclear distancesof the inner radio lobes and intermediate radio ridges, respectively. Wespeculate that these discontinuities may be spherical pulses or "fronts" drivenby the same jet activity as is responsible for the radio structure; such pulsesare found in recent numerical simulations. All these results provide goodevidence that the nuclear activity affects the intra-cluster medium. We presenta temperature map of the intra-cluster medium, and obtain the temperature,pressure and cooling time as a function of nuclear distance for the arcs andthe ambient intra-cluster medium. We show that the gas in the arcs is coolerthan, and probably over-pressured with respect to, the ambient intra-clustermedium. The metal abundances of the cooler gas in the arc are somewhat enhancedrelative to the ambient intra-cluster medium, favoring a ``buoyant plume''origin for the X-ray arc, in which ambient gas near the nucleus is entrained bybuoyant radio plasma and carried to larger nuclear distances. (Abstracttruncated).