A catalog of narrow-line Seyfert 1 galaxies in the southern hemisphere

TL;DR

This paper introduces a new, accurately classified sample of 167 narrow-line Seyfert 1 galaxies in the southern hemisphere, including spectral, radio, and X-ray data, with analysis of their properties.

Contribution

It provides the first flux-calibrated spectra for these NLS1s and offers new insights into their luminosity correlations, black hole masses, and radio properties.

Findings

Strong luminosity correlations between continuum and emission lines

Estimated black hole masses and Eddington ratios within typical NLS1 ranges

Detection of radio emission in 23 NLS1s, with 12 being radio-loud

Abstract

We present a new accurate sample of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS). Based on the optical spectral features, 167 sources were classified as NLS1s. We derived flux-calibrated spectra in the sample for the first time. Strong luminosity correlations between the continuum and the emission lines were found. We estimated their central black hole masses and Eddington ratios, which are lying in a typical range of NLS1s. In the sample, 23 NLS1s were detected at radio frequencies and 12 of them are radio-loud. We publish the X-ray data analysis of a campaign of observations carried out by the Swift X-ray Telescope.