X-ray spectral features and classification of selected QSOs

TL;DR

This study systematically analyzes XMM-Newton spectra of nearby bright QSOs to characterize their X-ray spectral features, revealing typical steep spectra, specific iron line detections, and spectral properties across different quasar types.

Contribution

It provides a detailed spectral analysis of selected QSOs, highlighting spectral characteristics and differences between radio-loud and radio-quiet quasars, with new insights into their X-ray properties.

Findings

Most sources have steep spectra with Gamma > 2.1

Detected Fe K-alpha line in two radio-loud type II quasars

No significant spectral hardening above 2 keV observed

Abstract

We present the results of a systematic analysis of the XMM-Newton spectra of nearby optically bright QSOs. The objects have been selected from X-ray Galaxy Catalog Xgal20. It is a catalog of 1172 manually identified and classified galaxies, obtained as a cross-correlation between the 4XMM-DR9 catalog and the Hyper-Linked Extragalactic Databases and Archives (HyperLeda) with an X-ray flux greater than 1E-13 erg/cm^2/s. The goal of this work is to characterize the X-ray spectral properties of selected QSOs in the 0.1 - 10 keV energy band. The majority of the sources (6 out of 11), are classified as radio-quiet QSOs. We studied optical spectra, hardness ratios and performed X-ray spectral fits for the 10 brighter sources. In most cases, the power law model with absorption is good enough to simulate observed continua. Although the details of the spectrum in some sources significantly complicate the model for fitting. The majority of sources have steep spectra Gamma > 2.1. Extremely steep photon index 2.4 - 2.5 in our sample occurs for three radio-loud type I quasars. We detected Fe K-alpha line for two radio-loud type II quasars. We find no strong evidence for spectral hardening above 2 keV neither for quasars of type I nor for obscured type II. For each quasar its type was established both based on the features and details of observed X-ray spectrum and previous data.