Investigating the Candidate Displaced Active Galactic Nucleus in NGC 3115

Abstract

The nearby galaxy NGC 3115 contains a known radio-emitting, low-luminosity active galactic nucleus (AGN), and was recently claimed to host a candidate AGN displaced 14.3 pc from the galaxy's optical photocenter. Our goal is to understand whether this represents a single offset AGN, an AGN in orbit around a central black hole, or something else. We present a new, sensitive (RMS = 4.4 $\mu$Jy beam${}^{-1}$) 10 GHz image, which finds evidence for only one AGN. We place a stringent limit on the radio luminosity of any secondary supermassive black hole of $L_{10\mathrm{GHz}}<5.8\times 10^{33}$ ergs/s. An analysis of the relative positioning of the radio core, X-ray nucleus, and stellar bulge in this galaxy indicate that the radio source is centrally located, and not offset from the galactic bulge. This provides an argument against a single offset AGN in NGC 3115, however does not provide conclusive evidence against the purported offset AGN as an in-spiralling secondary black hole.

Accepted to ApJ

References in corpus (5)

• A Compact Supermassive Binary Black Hole System
• The faint radio sky: radio astronomy becomes mainstream
• Recoiling black holes: electromagnetic signatures, candidates, and astrophysical implications
• Recoiling Supermassive Black Holes: a search in the Nearby Universe
• An off-centered active galactic nucleus in NGC 3115

Cited by in corpus (1)

• Evaluating the efficacy of a data cube treatment procedure for kinematic analyses: application to NGC 3115 and NGC 4699