AGN orientation through the spectroscopic correlations and model of dusty cone shell

TL;DR

This paper explores how the orientation and structure of dusty cones in AGNs influence spectroscopic correlations, particularly FWHM(Hb)-luminosity, suggesting inclination effects and dust geometry are key factors in AGN classification.

Contribution

It introduces a simple dusty cone model combined with a broad line region to explain spectroscopic correlations and the differences between NLS1s and BLAGNs, highlighting inclination effects.

Findings

Model reproduces observed FWHM(Hb)-luminosity correlations.

Inclination and dust structure influence AGN spectral properties.

NLS1s may be viewed at lower inclination angles.

Abstract

The differences between Narrow Line Seyfert 1 galaxies (NLS1s) and Broad Line AGNs (BLAGNs) are not completely understood; it is thought that they may have different inclinations and/or physical characteristics. The FWHM(Hb)-luminosities correlations are found for NLS1s and their origin is the matter of debate. Here we investigated the spectroscopic parameters and their correlations considering a dusty, cone model of AGN. We apply a simple conical dust distribution (spreading out of broad line region, BLR), assuming that the observed surface of the model is in a good correlation with MIR emission. The dusty cone model in combination with a BLR provides the possibility to estimate luminosity dependence on the cone inclination. The FWHM(Hb)-luminosities correlations obtained from model in comparison with observational data show similarities which may indicate the influence of AGN inclination and structure to this correlation. An alternative explanation for FWHM(Hb)-luminosities correlations is the selection effect by the black hole mass. These FWHM(Hb)-luminosities correlations may be related to the starburst in AGNs, as well. The distinction between spectral properties of the NLS1s and BLAGNs could be caused by multiple effects: beside physical differencies between NLS1s and BLAGNs (NLS1s have lighter black hole mass than BLAGNs), inclination of the conical AGN geometry may have important role as well, where NLS1s may be seen in lower inclination angles.