A Candidate Dual AGN in a Double-peaked Emission-line Galaxy with Precessing Radio Jets

TL;DR

This study uses high-resolution radio observations to analyze a galaxy with double-peaked emission lines, revealing precessing jets likely caused by a single or dual supermassive black hole system, with implications for understanding AGN dynamics.

Contribution

It presents the first detailed modeling of precessing jets in 2MASXJ1203, linking jet morphology to possible SMBH configurations and estimating precession timescales and black hole separations.

Findings

Radio jets exhibit a helical, S-shaped morphology consistent with precession.

Precession timescale estimated at around 10^5 years, matching spectral aging.

Dual SMBH separation estimated at 0.02 pc, but orbital dynamics suggest alternative causes for jet precession.

Abstract

We present high resolution radio continuum observations with the Karl G. Jansky Very Large Array at 6, 8.5, 11.5 and 15 GHz of the double-peaked emission-line galaxy 2MASXJ12032061+1319316. The radio emission has a prominent S-shaped morphology with highly symmetric radio jets that extend over a distance of $\sim1.5^{\prime\prime}$ (1.74~kpc) on either side of the core of size $\sim0.1^{\prime\prime}$(116~pc). The radio jets have a helical structure resembling the precessing jets in the galaxy NGC~326 which has confirmed dual active galactic nuclei (AGN). The nuclear bulge velocity dispersion gives an upper limit of $(1.56\pm$0.26$)\times$10$^8$~M$_{\odot}$ for the total mass of nuclear black hole(s). We present a simple model of precessing jets in 2MASXJ1203 and find that the precession timescale is around 10$^5$ years: this matches the source lifetime estimate via spectral aging. We find that the expected super massive black hole (SMBH) separation corresponding to this timescale is 0.02 pc. We used the double peaked emission lines in 2MASXJ1203 to determine an orbital speed for a dual AGN system and the associated jet precession timescale, which turns out to be more than the Hubble time, making it unfeasible. We conclude that the S-shaped radio jets are due to jet precession caused either by a binary/dual SMBH system, a single SMBH with a tilted accretion disk or a dual AGN system where a close pass of the secondary SMBH in the past has given rise to jet precession.