A Deep 0.3-10 keV Spectrum of the H$_{2}$O Maser Galaxy IC 2560

TL;DR

This paper presents a detailed X-ray spectral analysis of IC 2560, revealing high obscuration, reflection features, and ionized gas, and compares these with water maser emission to understand AGN disk structures.

Contribution

It provides the first detailed XMM-Newton spectrum of IC 2560, highlighting high column density, reflection components, and the connection between X-ray features and maser disk properties.

Findings

High obscuration with N_H > 10^24 cm^-2

Detection of a 6.7 keV FeXXV emission line

Correlation between maser disk conditions and AGN luminosity

Abstract

We present a new XMM-Newton spectrum of the Seyfert 2 nucleus of IC 2560, which hosts H$_{2}$O maser emission from an inclined Keplerian accretion disk. The X-ray spectrum shows soft excess due to multi-temperature ionized plasma, a hard continuum and strong emission features, from Mg, Si, S, Ca, Fe and Ni, mainly due to fluorescence. It is consistent with reflection of the continuum from a mostly neutral medium and obscuration due to a high column density, $>$ 10$^{24}$ cm$^{-2}$. The amplitude of the reflected component may exceed 10% of the central unobscured luminosity. This is higher than the reflected fraction, of a few percent, observed in other Seyfert 2 sources like NGC 4945. We observe an emission line at 6.7 keV, possibly due to FeXXV, undetected in previous Chandra observations. The absorption column density associated with this line is less than 10$^{23}$ cm$^{-2}$, lower than the obscuration of the central source. We hypothesize that this highly ionized Fe line emission originates in warm gas, also responsible for a scattered component of continuum emission that may dominate the spectrum between 1 and 3 keV. We compare X-ray and maser emission characteristics of IC 2560 and other AGN that exhibit water maser emission originating in disk structures around central engines. The temperature for the region of the disk associated with maser action is consistent with the expected 400-1000K range. The clumpiness of disk structures (inferred from the maser distribution) may depend on the unobscured luminosities of the central engines.