The Complex X-ray Spectrum of the Sefyert 1.5 Source NGC 6860

TL;DR

This paper analyzes complex X-ray spectra of Seyfert 1.5 galaxy NGC 6860 using Suzaku and XMM-Newton data, revealing warm absorbers and a broad Fe K-alpha line, highlighting spectral variability and absorption features.

Contribution

It provides a detailed spectral analysis of NGC 6860, identifying warm ionized absorbers and a broad Fe K-alpha line, advancing understanding of Seyfert galaxy X-ray spectra.

Findings

Detection of two warm ionized absorbers with distinct properties.

Observation of a broad, redshifted Fe K-alpha emission line.

Spectral variability between observations indicating changing source conditions.

Abstract

The X-ray spectrum of the Seyfert 1.5 source NGC 6860 is among the most complex of the sources detected in the Swift Burst Alert Telescope all-sky survey. A short XMM-Newton follow-up observation of the source revealed a flat spectrum both above and below 2 keV. To uncover the complexity of the source, in this paper we analyze both a 40 ks Suzaku and a 100 ks XMM-Newton observation of NGC 6860. While the spectral state of the source changed between the newer observations presented here and the earlier short XMM-Newton spectrum - showing a higher flux and steeper power law component - the spectrum of NGC 6860 is still complex with clearly detected warm absorption signatures. We find that a two component warm ionized absorber is present in the soft spectrum, with column densities of about 10^20 and 10^21 cm$^-2, ionization parameters of xi = 180 and 45 ergs cm s^-1, and outflow velocities for each component in the range of 0-300 km s^-1. Additionally, in the hard spectrum we find a broad (approx 11000 km s^-1) Fe K-alpha emission line, redshifted by approx 2800 km s^-1.