A Fanaroff-Riley Type I Candidate in Narrow-Line Seyfert 1 Galaxy Mrk 1239

TL;DR

This study reveals that the NLS1 galaxy Mrk 1239 hosts a jet-producing engine similar to radio-loud AGNs, with kiloparsec-scale radio emissions and jet power comparable to FR I radio galaxies, despite being radio-quiet.

Contribution

First detection of kiloparsec-scale radio jets in a radio-quiet NLS1 galaxy, showing jet formation mechanisms similar to those in radio-loud AGNs.

Findings

Radio emissions aligned with parsec-scale jets in Mrk 1239.

Jet kinetic power comparable to Fanaroff--Riley Type I radio galaxies.

Inefficient conversion from accretion to jet power in this low-mass black hole system.

Abstract

We report finding kiloparsec-scale radio emissions aligned with parsec-scale jet structures in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 1239 using the Very Large Array and the Very Long Baseline Array. Thus, this radio-quiet NLS1 has a jet-producing central engine driven by essentially the same mechanism as that of other radio-loud active galactic nuclei (AGNs). Most of the radio luminosity is concentrated within 100 parsecs and overall radio morphology looks edge-darkened; the estimated jet kinetic power is comparable to Fanaroff--Riley Type I radio galaxies. The conversion from accretion to jet power appears to be highly inefficient in this highly accreting low-mass black hole system compared with that in a low-luminosity AGN with similar radio power driven by a sub-Eddington, high-mass black hole. Thus, Mrk 1239 is a crucial probe to the unexplored parameter spaces of central engines for a jet formation.