On the orientation of Narrow Line Seyfert I

TL;DR

This paper investigates the differences among Narrow-line Seyfert 1 galaxies by analyzing their optical and radio features, proposing a geometrical model that attributes observed variations to jet orientation, and estimating the fraction of jetted sources.

Contribution

It introduces a geometrical model explaining NLS1 radio features based on jet orientation and estimates a higher fraction of jetted sources than in standard AGN.

Findings

Redshift and mass differences are due to observational biases.

Most observational features are explained by jet orientation.

The fraction of jetted NLS1s is larger than in typical AGN.

Abstract

We study a sample of Narrow-line Seyfert 1 galaxies (NLS1) in their optical and radio features, in order to understand the differences between their radio silent, radio-loud and radio-quiet subclasses. We first show that the different redshift and mass distributions of radio-loud and -quiet NLS1s could be ascribed to observational biases. We then present a geometrical model according to which most of the different observational features of radio-loud and radio-quiet NLS1s are ascribed to the orientation of an intrinsically structured jet. We estimate the fraction of intrinsically jetted sources among NLS1s that justifies the observed radio-detected population. Noticeably, under the assumptions of the geometrical model, we derive a fraction of jetted sources significantly larger than in standard AGN.