The jet-cloud interacting radio galaxy PKS B2152-699. I. Structures revealed in new deep radio and X-ray observations

摘要

PKS B2152-699 has radio power characteristic of sources that dominate radiofeedback. We present new deep ATCA, Chandra and optical observations, and testthe feedback model. We report the first high-resolution observations of theradio jet. The inner jet extends ~8.5 kpc towards an optical emission-line HighIonization Cloud (HIC) before taking a zig-zag path to an offset position. JetX-ray synchrotron radiation is seen. The HIC is associated with 0.3 keV X-raygas of anomalously low metallicity. On larger scales the radio galaxy displaysall three X-ray features that together confirm supersonic expansion of thelobes into the external medium: gas cavities, inverse-Compton emission showingexcess internal lobe pressure, and high-contrast arms of temperature above the~1 keV ambient medium. The well-formed S lobe on the counterjet side isexpanding with a Mach number 2.2-3. We estimate a cavity power ~3x10^43 ergs/s,which falls well below previously reported correlations with radio power. Thetotal inferred time-averaged jet power, ~4x10^44 ergs/s, is dominated by thekinetic and thermal energy of shocked gas, and if used instead would bring thesource into better agreement with the correlations. The S hotspot is the morecomplex, with a spiral polarization structure. Its bright peak emitssynchrotron X-rays. The fainter N hotspot is particularly interesting, withX-rays offset in the direction of the incoming jet by ~1 arcsec relative to theradio peak. Here modest (delta ~ 6) relativistic beaming and a steep radiospectrum cause the jet to be X-ray bright through inverse-Compton scatteringbefore it decelerates. With such beaming, a modest proton content or smalldeparture from minimum energy in the jet will align estimates of theinstantaneous and time-averaged jet power. The hotspots suggest acceleration ofelectrons to a maximum energy ~10^13 eV in the jet termination shocks.