Spectral Survey of X-Ray Bright Active Galactic Nuclei from the Rossi X-ray Timing Explorer

TL;DR

This paper presents a comprehensive long-term spectral survey of 23 active galactic nuclei using RXTE data, providing valuable baseline measurements of their X-ray properties and confirming features like the Compton reflection component.

Contribution

It offers the first extensive long-term average spectra of AGN in the 3-100 keV range, improving accuracy and sensitivity over previous surveys and analyzing spectral features.

Findings

Tentative evidence for high-energy rollovers in three AGN.

Improved measurements of Compton reflection strength.

Long-term average spectral parameters for 23 AGN.

Abstract

Using long-term monitoring data from the Rossi X-ray Timing Explorer (RXTE), we have selected 23 active galactic nuclei (AGN) with sufficient brightness and overall observation time to derive broadband X-ray spectra from 3 to >100 keV. Our sample includes mainly radio-quiet Seyferts, as well as seven radio-loud sources. Given the longevity of the RXTE mission, the greater part of our data is spread out over more than a decade, providing truly long-term average spectra and eliminating inconsistencies arising from variability. We present long-term average values of absorption, Fe line parameters, Compton reflection strengths and photon indices, as well as fluxes and luminosities for the hard and very hard energy bands, 2-10 keV and 20-100 keV respectively. We find tentative evidence for high-energy rollovers in three of our objects. We improve upon previous surveys of the very hard X-ray energy band in terms of accuracy and sensitivity, particularly with respect to confirming and quantifying the Compton reflection component. This survey is meant to provide a baseline for future analysis with respect to the long-term averages for these sources and to cement the legacy of RXTE, and especially its High Energy X-ray Timing Experiment, as a contributor to AGN spectral science.