The Halo , Hot Spots and Jet / Cloud Interaction of Pks 2153 – 69

We report Chandra X-ray Observatory and 1.4 GHz Australian Long Baseline Array (LBA) observations of the radio galaxy PKS 2153–69 and its environment. The Chandra image reveals a roughly spherical halo of hot gas extending out to 30 kpc around PKS 2153–69. Two depressions in the surface brightness of the X-ray halo correspond to the large scale radio lobes, and interpreting these as cavities inflated with radio plasma we infer a jet power of 4 × 10 42 erg s −1. Both radio lobes contain hot spots that are detected by Chandra. In addition, the southern hot spot is detected in the 1.4 GHz LBA observation , providing the highest linear resolution image of a radio lobe hot spot to date. The northern hot spot was not detected in the LBA observation. The radio to X-ray spectra of the hot spots are consistent with a simple power law emission model. The nucleus has an X-ray spectrum typical of a type 1 active galactic nucleus, and the LBA observation shows a one-sided nuclear jet on 0. ′′ 1 scales. Approximately 10 ′′ northeast of the nucleus, X-ray emission is associated with an extra-nuclear cloud. The X-ray emission from the cloud can be divided into two regions, an unresolved western component associated with a knot of radio emission (in a low resolution map), and a spatially extended eastern component aligned with the pc-scale jet and associated with highly ionized optical line-emitting clouds. The X-ray spectrum of the eastern component is very soft (Γ > 4.0 for a power law model or kT ≃ 0.22 keV for a thermal plasma). The LBA observation did not detect compact radio emission from the extra-nuclear cloud. We discuss both jet precession and jet deflection models to account for the progressively increasing position angle from the northern hot spot to the western component of the jet/cloud interaction region to the direction of the pc-scale jet. In the precession model the particle beam impacts the western region while the radiation beamed from the nucleus photoionizes the eastern region and is scattered into our line of sight by dust giving rise to the polarized optical emission and possibly the soft X-ray emission. If the X-ray emission from the eastern region really is dust-scattered nuclear radiation, it would be the first detection of such emission from an external galaxy. The nearby galaxy MRC 2153–699 is also detected by Chandra. The …