The Jet/ISM Interaction in Three Nearby Radio Galaxies as seen with Chandra

Chandra observations of radio galaxies have demonstrated a wide range of complex interactions between their jets and the ambient interstellar/intracluster medium (ISM/ICM). In this paper, we discuss results from Chandra observations of jet/ISM interactions in three nearby radio galaxies: Centaurus A (3.4 Mpc), M87 (16 Mpc), and NGC507 (66.7 Mpc). We present observational details for each object, and discuss how these relate to the more general picture of jet/ISM interactions. In Centaurus A, we have detected a hot, dense shell of gas surrounding the southwest radio lobe that we attribute to the supersonic expansion of the lobe into the ISM. There is some evidence of a similar interaction around the northeast radio lobe, although two orders of magnitude less X-ray luminous. We discuss the implications of this shell and the asymmetry. A deep Chandra observation (100 ks) of M87 indicates complex structures over a range of scales. Features include several X-ray cavities related to the radio cocoon in the central 45 , an X-ray cavity coincident with a radio feature that lies perpendicular to the jet/counter jet axis suggestive of a buoyant bubble, and several roughly concentric surface brightness discontinuities in the larger scale gas indicative of shocks produced by multiple radio outbursts. Chandra observations of NGC507 have detected a large surface brightness discontinuity related to the expansion of the radio lobes. The temperature difference across the discontinuity is small ( 10%), so that this is not a ‘cold-front’ of the type that has been commonly seen by Chandra in cluster mergers. The appearance of this feature is most likely due to the entrainment of higher abundance gas from the central regions of the galaxy as the lobe expands at roughly the sound speed of the ambient gas.