2013MNRAS.435.3385P

We present an X-ray study of the nuclear and extended emission of a nearby Fanaroff & Riley class I (FR-I) radio galaxy CTD 86 based on the XMM-Newton observations. Two different components observed are: diffuse thermal emission from hot gas (kT ∼ 0.79keV, ne ∼ 10^–3/cm3, LX ∼ 5x10⁴²erg/s extended over ∼ 186kpc), and unresolved nuclear emission exhibiting mild activity. The hot gaseous environment of CTD 86 is similar to that found in groups of galaxies or in bright early-type galaxies. No clear signatures of radio-lobe interaction with the diffuse hot gas are evident in this case. X-ray emission from the nucleus is well constrained by an intrinsically absorbed (NH ∼ 5.9x10²²/cm2) power law (Γ ∼ 1.5) with 2-10keV luminosity LX ∼ 2.1x10⁴²erg/s. We have measured the stellar velocity dispersion, σ = 182±8km/s, for the CTD 86 and estimated a mass MBH ∼ 9x10⁷M_☉ with Lbol/LEdd ∼ 4x10^–3. The low Lbol/LEdd rate and high L_X/L_[O III] ratio suggest that the central engine of CTD 86 consists of a truncated accretion disc lacking a strong ionizing ultraviolet radiation and an inner hot flow producing the X-ray emission. The truncated disc is likely to be inclined with (i ∼ 40°-50°) such that our line of sight passes through the outer regions of a putative torus and thus results in high X-ray absorption. We have also identified two bright X-ray sources: SDSS J142452.11+263715.1 and SDSS J142443.78+263616.2, near CTD 86. SDSS J142452.11+263715.1 is a type 1 active galactic nucleus at z = 0.3761 and unabsorbed 0.3-10keV X-ray luminosity LX ∼ 8x10⁴³erg/s, while SDSS J142443.78+263616.2 is probably a galaxy with an active nucleus.