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

• Published in: The Astrophysical journal 2020-12, Vol.905 (2), p.148
• Main Authors: Balasubramaniam, K., Stawarz, ., Marchenko, V., Sobolewska, M., Cheung, C. C., Siemiginowska, A., Thimmappa, R., Kosmaczewski, E.
• Format: Article
• Language: English
• Subjects: Active galaxies; Astrophysics; Emission; Galaxies; Hydrogen; Intergalactic medium; Interstellar matter; Interstellar medium; Iron; K alpha line; LINER galaxies; Linings; Low-luminosity active galactic nuclei; Photoionization; Radio galaxies; Relativistic jets; Stars & galaxies; Thermal plasmas; X ray spectra; X-ray active galactic nuclei; X-ray emissions; X-rays
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abc4e2

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 × 1023 cm−2), and partly scattered (fraction ∼3%) by ionized gas, giving rise to a soft excess component and K line from iron ions. We demonstrate that the observed X-ray spectrum, particularly the equivalent width of Fe XXV K (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.