Extended emission-line regions in low-redshift quasars: Dependence on nuclear spectral properties

TL;DR

This study investigates the occurrence of extended emission-line regions around low-redshift quasars, revealing their dependence on nuclear spectral properties and black hole mass, with a significant fraction showing luminous EELRs.

Contribution

It provides new insights into the relationship between EELRs and nuclear spectral features in low-redshift quasars using integral field spectroscopy.

Findings

8 out of 20 quasars have luminous EELRs

EELR presence correlates with low FeII equivalent width and large Hbeta FWHM

EELRs are more common in quasars with larger black hole masses

Abstract

We searched for the presence of extended emission-line regions (EELRs) around low-redshift QSOs. We observed a sample of 20 mainly radio-quiet low-redshift quasars (z<0.3) by means of integral field spectroscopy. After decomposing the extended and nuclear emission components, we constructed [OIII] 5007 narrow-band images of the EELR to measure the total flux. From the same data we obtained high S/N (>50) nuclear spectra to measure properties such as [OIII]/Hbeta flux ratios, FeII equivalent widths and Hbeta line widths. A significant fraction of the quasars (8/20) show a luminous EELR, with detected linear sizes of several kpc. Whether or not a QSO has a luminous EELR is strongly related with nuclear properties, in the sense that an EELR was detected in objects with low FeII equivalent width and large Hbeta FWHM. The EELRs were detected preferentially in QSOs with larger black hole masses. There is no discernible relation, however, between EELR detection and QSO luminosity and Eddington ratio.