The Giant Radio Galaxy MRC B0319–454: Circumnuclear Structure of the Host Galaxy ESO 248-G10

摘要

We present optical and near-infrared images and spectra of ESO 248-G10, the host of the giant radio galaxy MRC B0319-454. From near-infrared colors, the active nucleus is shown to be reddened by hot dust emission or dust extinction. Star-forming regions are identified beyond a radius of 5'' (8.1 kpc) where hot gas is prevalent. The optical spectrum shows gas rotation at speeds of up to ~350 km s-1 out to ≥32 kpc along the radio axis. A model is proposed in which the giant elliptical is triaxial with the radio axis along the short axis, and the figure rotation is around the long axis. From the model, the angles of the principal axis are ψ = 34°, θ = 65°, and = 19° with axis ratios of B/A = 0.75 and C/A = 0.69. A second velocity feature from 5'' to 15'' to the northeast of the nucleus is proposed to be a merging gas-rich galaxy inducing star formation while settling into an orbit about the figure rotation axis.