Modelling the quasar spectra for super-Eddington sources -- The What, the Why and the How

TL;DR

This paper investigates the impact of anisotropic continuum radiation from super-Eddington quasars on the broad line region, using photoionization models to understand the physical conditions and diversity of active galactic nuclei.

Contribution

It introduces a model accounting for anisotropic continuum radiation due to funnel-like structures near supermassive black holes, linking super-Eddington sources to the main sequence of quasars.

Findings

Super-Eddington sources can be located along the quasar main sequence.

Anisotropic radiation significantly influences the physical conditions of the broad line region.

The model constrains the properties of the line-emitting gas in active galaxies.

Abstract

Broad lines in active galaxies are primarily emitted by photoionization processes that are driven by the incident continuum arising from a complex geometrical structure circumscribing the supermassive black hole. A model of the broad-band spectral energy distribution (SED) effective in ionizing the gas-rich broad line emitting region (BLR) is needed to understand the various radiative processes that eventually lead to the emission of emission lines from diverse physical conditions. Photoionization codes are a useful tool to investigate two aspects - the importance of the shape of the SED, and the physical conditions in the BLR. In this work, we focus on the anisotropy of continuum radiation from the very centre a direct consequence of the development of a funnel-like structure at regions very close to the black hole. Accounting for the diversity of Type-1 active galactic nuclei (AGNs) in the context of the main sequence of quasars permits us to locate the super Eddington sources along the sequence and constrain the physical conditions of their line-emitting BLR.