Reaching the Peak of the Quasar Spectral Energy Distribution I: Observations and Models

TL;DR

This study analyzes the spectral energy distributions of 11 medium-redshift quasars using multi-wavelength data to model their accretion processes and estimate their bolometric luminosities, revealing potential limitations of common estimation methods.

Contribution

It introduces a comprehensive multi-wavelength spectral analysis of quasars with a new accretion model, highlighting the challenges in accurately estimating bolometric luminosities.

Findings

Five quasars show evidence of an SED peak.

Bolometric luminosities may be unreliable when estimated from L_5100A and L_2-10keV.

The study provides constraints on black hole masses and accretion rates.

Abstract

We perform a spectral analysis of a sample of 11 medium redshift (1.5 < z < 2.2) quasars. Our sample all have optical spectra from the SDSS, infrared spectra from GNIRS and TSPEC, and X-ray spectra from XMM-Newton. We first analyse the Balmer broad emission line profiles which are shifted into the IR spectra to constrain black hole masses. Then we fit an energy-conserving, three component accretion model of the broadband spectral energy distribution (SED) to our multi-wavelength data. Five out of the 11 quasars show evidence of an SED peak, allowing us to constrain their bolometric luminosity from these models and estimate their mass accretion rates. Based on our limited sample, we suggest that estimating bolometric luminosities from L_5100A and L_2-10keV may be unreliable, as has been also noted for a low-redshift, X-ray selected AGN sample.