X–ray and Optical Filaments in M87

We compare a very deep X–ray image of M87, at the center of the Virgo Cluster, to high-quality optical images of the low excitation emission-line gas in the same region. There are striking coincidences of detail between the two. We explore the possiblity that this represents a thermal interaction between hot gas at 10 K and warm gas at 10 K. We find two temperatures are present in the X–ray gas, with the lower more prevelant in the vicinity of the optical filaments. Electron conduction from the hot phase to the cooler one provides a quantitatively acceptable energy source for the optical filaments, and we show additionally that it can do so for the brightest X–ray cluster, Perseus. If operative, conduction in the presence of gas-rich galaxy mergers, may explain the presence of “cool cores” in clusters of galaxies. Subject headings: galaxies: individual (M87), galaxies: ISM, X–rays: galaxies: clusters