Is There a Blazar Nested in the Core of the Radio Galaxy 3C 411?

Abstract

Abstract Previous spectral energy distribution modeling based on XMM-Newton X-ray observation of the classical double-lobed radio galaxy 3C 411 left the possibility open for the presence of a blazar-like core. We investigated this scenario by characterizing the radio brightness distribution in the inner ∼10 pc region of the source. We applied the very long baseline interferometry (VLBI) technique at four different frequencies from 1.7 to 7.6 GHz. We analyzed archival data from the Very Long Baseline Array taken in 2014, and data from the European VLBI Network obtained in 2017. The VLBI images reveal parsec-scale extended structure in the core of 3C 411 that can be modeled with multiple jet components. The measured core brightness temperatures indicate no Doppler enhancement that would be expected from a blazar jet pointing close to the line of sight. While there is no blazar-type core in 3C 411, we found an indication of flux density variability. The overall morphology of the source is consistent with a straight jet with ∼50° inclination angle at all scales from parsecs to kiloparsecs.