Radio-emitting narrow-line Seyfert 1 galaxies in the JVLA perspective

TL;DR

This study uses JVLA radio observations to classify and compare the morphologies of different types of narrow-line Seyfert 1 galaxies, revealing distinct structural properties and potential evolutionary links.

Contribution

It presents the largest radio survey of NLS1s, identifying morphological differences among subclasses and suggesting evolutionary connections, especially between flat-spectrum and steep-spectrum radio-loud NLS1s.

Findings

F-NLS1s are more compact and possibly young blazars.

RQNLS1s often show diffuse, kpc-scale emission.

S-NLS1s are likely part of the parent population of F-NLS1s.

Abstract

We report the first results of a survey on 74 narrow-line Seyfert 1 galaxies (NLS1s) carried out in 2015 with the Karl G. Jansky Very Large Array (JVLA) at 5 GHz in A-configuration. So far, this is the largest survey aimed to image the radio continuum of NLS1s. We produced radio maps in order to compare the general properties of three different samples of objects: radio-quiet NLS1s (RQNLS1s), steep-spectrum radio-loud NLS1s (S-NLS1s), and flat-spectrum radio-loud NLS1s (F-NLS1s). We find that the three classes correspond to different radio morphologies, with F-NLS1s being more compact, and RQNLS1s often showing diffuse emission on kpc scales. We also find that F-NLS1s might be low-luminosity and possibly young blazars, and that S-NLS1s are part of the parent population of F-NLS1s. Dedicated studies to RQNLS1s are needed in order to fully understand their role in the unification pictures.