Chandra View of the LINER-type Nucleus in the Radio-loud Galaxy CGCG 292–057: Ionized Iron Line and Jet–ISM Interactions

Abstract

We present an analysis of the new, deep (94 ksec) Chandra ACIS-S observation of radio-loud active galaxy CGCG 292−057, characterized by a LINER-type nucleus and a complex radio structure that indicates intermittent jet activity. On the scale of the host galaxy bulge, we detected excess X-ray emission with a spectrum best fit by a thermal plasma model with a temperature of ∼0.8 keV. We argue that this excess emission results from compression and heating of the hot diffuse fraction of the interstellar medium displaced by the expanding inner, ∼20 kpc-scale lobes observed in this restarted radio galaxy. The nuclear X-ray spectrum of the target clearly displays an ionized iron line at ∼6.7 keV, and is best fitted with a phenomenological model consisting of a power-law (photon index  ≃ 1.8) continuum absorbed by a relatively large amount of cold matter (hydrogen column density  ≃0.7 × 10 23 cm −2 ), and partly scattered (fraction ∼3%) by ionized gas, giving rise to a soft excess component and K α line from iron ions. We demonstrate that the observed X-ray spectrum, particularly the equivalent width of Fe XXV K α (of order 0.3 keV) can in principle, be explained in a scenario involving a Compton-thin gas located at the scale of the broad-lined region in this source and photoionized by nuclear illumination. We compare the general spectral properties of the CGCG 292−057 nucleus, with those of other nearby LINERs studied in X-rays.