A multi-wavelength study of nuclear activity and environment of low-power radio galaxy CTD 86

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 ∼ 0.79 keV, n_e ∼ 10^-3 cm^-3, L_X ∼ 5 × 10⁴² erg s^{- 1} extended over ∼186 kpc), 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 (N_H ∼ 5.9 × 10²² cm^-2) power law (Γ ∼ 1.5) with 2-10 keV luminosity L_X ∼ 2.1 × 10⁴² erg s^-1. We have measured the stellar velocity dispersion, σ = 182 ± 8 km s^-1, for the CTD 86 and estimated a mass M_BH ∼ 9 × 10⁷ M_⊙ with L_bol/L_Edd ∼ 4 × 10^-3. The low L_bol/L_Edd 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 0.3-10 keV X-ray luminosity L_X ∼ 8 × 10⁴³ erg s^-1, while SDSS J142443.78+263616.2 is probably a galaxy with an active nucleus.