A candidate dual AGN in a double-peaked emission-line galaxy with precessing radio jets

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 ∼ 1.5 (1.74 kpc) on either side of the core of size ∼ 0.1 (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±0.26)×108 M 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.

Parsec-scale Nuclear Radio Structures in Seyfert Galaxies

“…New VLBA observations of the Seyfert DPAGN KISSR 434 have revealed an intriguing ∼ 150 parsec C-shaped curved jet, again suggesting jet-NLR interaction as the source of doublepeaked narrow emission lines (Kharb et al 2018b, in preparation). However, the curved jet itself could arise due to precession in a binary black hole system [e.g., see 39,40]. Interestingly, we have found suggestions of a binary black hole system through multi-frequency VLBA observations of the Seyfert / luminous infrared galaxy (LIRG) NGC 7674 [41].…”

Spatially offset AGN candidates in the CLASS survey

“…Barrows et al 2016) or are double-peaked (e.g. Rubinur et al 2017;Tytler & Browne 1985). However, some follow-up surveys (e.g.…”

Multiwavelength observations of the triple-peaked AGN Mrk 622

“…Up to recently, only one object is considered to be a confirmed binary AGN that has two SMBHs separated by 7 pc (Rodriguez et al 2006). A few candidates of binary SMBHs have since been suggested by (e.g., Kharb et al 2017a;Rubinur et al 2017). Insofar as dual-AGN, very few have been confirmed (see Rubinur et al 2019).…”

“…Initially, finding AGN that show double or triple peak narrow emission lines in their spectra was considered as evidence for harboring dual or binary AGN (Wang et al 2009;Liu et al 2010;Smith et al 2010;Fischer et al 2011). However, double-peaked emission lines can instead be trac-ing AGN with peculiar kinematics, such as biconical outflows, winds, jet-cloud interactions (e.g., Crenshaw & Kraemer 2000;Xu & Komossa 2009;Fischer et al 2011;Rubinur et al 2017;Kharb et al 2017b;Jaiswal et al 2019). Hence, double-peaked narrow emission lines are rarely found to be due to a dual or binary AGN system(e.g., Nevin et al 2016;Comerford et al 2018) and follow-up observations are therefore necessary to confirm the existence of a SMBHs pair among the available candidates.…”