FeII strength in NLS1s -- dependence on the viewing angle and FWHM

TL;DR

This study investigates how the FeII emission strength in NLS1 galaxies depends on the viewing angle and broad Hβ line width, using photoionization modeling to understand quasar orientation effects.

Contribution

It introduces a model incorporating the inclination angle and FWHM dependence on FeII strength, advancing the understanding of quasar spectral diversity.

Findings

FeII strength varies with viewing angle and FWHM

Eigenvector 1 parameter correlates with inclination and line width

Preliminary results support orientation-based explanations for spectral differences

Abstract

We address the effect of orientation of the accretion disk plane and the geometry of the broad-line region (BLR) in the context of understanding the distribution of quasars along their Main Sequence. We utilize the photoionization code CLOUDY to model the BLR, incorporating the `un-constant' virial factor. We show the preliminary results of the analysis to highlight the co-dependence of the Eigenvector 1 parameter, $\mathrm{R_{FeII}}$ on the broad H$\beta$ FWHM (i.e. the line dispersion) and the inclination angle ($\theta$), assuming fixed values for the Eddington ratio ($\mathrm{L_{bol}}/\mathrm{L_{Edd}}$), black hole mass ($\mathrm{M_{BH}}$), spectral energy distribution (SED) shape, cloud density (n$\rm{_{H}}$) and composition.