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

Abstract

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, ne ~ 10-3 cm-3, LX ~ 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 (NH ~ 5.9 × 1022 cm-2) power law (γ ~ 1.5) with 2-10 keV luminosity LX ~ 2.1 × 1042 erg s-1. We have measured the stellar velocity dispersion, σ =182±8 kms-1, for the CTD 86 and estimated a massMBH ~9×107M⊙ with Lbol/LEdd ~ 4 × 10-3. The lowLbol/LEdd rate and high LX/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 LX ~ 8 × 1043 erg s-1, while SDSS J142443.78+263616.2 is probably a galaxy with an active nucleus. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.