An XMM-Newton study of the sub-structure in M 87's halo

The high signal to noise and good point spread function of XMM have allowed the first detailed study of the interaction between the thermal and radio emitting plasma in the central regions of M 87. We show that the X-ray emit ting structure, previously seen by ROSAT, is thermal in nature and that the east and southwest extensions in M 87's X-ray; halo have a significantly l ower temperature (kT = 1.5 keV) than the surrounding ambient medium (kT = 2 .3 keV). There is little or no evidence for non-thermal emission with an up per limit on the contribution of a power law component of spectral index fl atter than 3 being less than 1% of the flux iu the region of the radio lobe s.