Identification of Large-Scale (>100 kpc) Radio Jets in Narrow-Line Seyfert 1 Galaxies

TL;DR

This study reports the discovery of 33 narrow-line Seyfert 1 galaxies with large-scale (>100 kpc) radio jets, challenging previous notions about galaxy types hosting such jets and highlighting the potential for more discoveries with future telescopes.

Contribution

The paper identifies and characterizes large-scale radio jets in NLSy1 galaxies, including the first known Mpc-scale jet in an NLSy1, expanding understanding of jet-hosting galaxy types.

Findings

33 NLSy1 galaxies with >100 kpc radio jets identified

One NLSy1 hosts a 4.3 Mpc radio jet, the largest known in this class

Future telescopes may reveal more large-scale jets in NLSy1s

Abstract

Powerful, large-scale relativistic jets are usually associated with massive, old elliptical galaxies. This paradigm has recently been challenged by the identification of narrow-line Seyfert 1 (NLSy1) galaxies, thought to be young active galactic nuclei with low-mass black holes, harboring relativistic jets. Among them, sources hosting $>$100 kpc radio jets are extremely rare. Here, we report the discovery of large-scale, double-lobed radio structures in 33 NLSy1s with the projected linear size of at least 100 kpc from a recently published catalog of 22656 NLSy1 galaxies. These 33 include 29 confirmed double-lobed sources and 4 candidates whose radio structure requires further study. We suggest that their low black hole masses are unlikely to be due to their small angles of inclination to the line of sight. These enigmatic sources were identified by examining the radio observations taken with the Faint Images of the Radio Sky at Twenty centimeters, Very Large Array Sky Survey, Low Frequency Array, and Rapid ASKAP Continuum Survey. Among them, the NLSy1 source J1318+2626 ($z=0.62$) is found to host a radio jet with the projected linear size of 4.3 Mpc, making it the only NLSy1 galaxy hosting a Mpc-scale radio jet known as of today. We conclude that future observations of NLSy1 sources with the next generation of sensitive telescopes may reveal a much larger population harboring large-scale jets, thus providing crucial clues on their origin, propagation, and interaction with the ambient environment.