THE MORPHOLOGY AND METAL ABUNDANCE OF M86 FROM ROSAT PSPC AND HRI OBSERVATIONS - DUST DESTRUCTION IN SUPERSONIC RAM-PRESSURE STRIPPING

From deep ROSAT PSPC and HRI observations of M86 (NGC 4406) we have mapped metal abundance and temperature changes across the image and detected significant structure in addition to the X-ray plume. We measure a high abundance in the plume of Z similar to 0.65(-0.2)(+0.4) Z., which is significantly higher than the abundance in the core of M86 ( similar to 0.3 +/- 0.1 Z.) or the cluster abundance (similar to 0.2 Z.). The spectra from regions larger than the inner few arcmin show an enhanced silicon abundance. The galaxy and the plume are at similar temperatures kT similar to 0.8 +/- 0.03 keV, compared to the cluster temperature of similar to 1.9 keV. The structures detected and the abundance measurements support the hypothesis that the Virgo ICM is ram-pressure stripping the ISM of M86 in a single blob. Dust in the stripped material, previously held within cold gas clouds, is being destroyed. The morphology and calculations of the ram pressure indicate that M86 may have a southwards velocity in the plane of the sky of similar to 500 km s(-1) compared to its radial velocity of 1374 km s(-1) relative to the cluster.