paper

X-ray Simulations of Polar Gas in Accreting Supermassive Black Holes

arXiv:2111.00065 · doi:10.1093/mnras/stab3178

Abstract

Recent observations have shown that a large portion of the mid--infrared (MIR) spectrum of active galactic nuclei (AGN) stems from the polar regions. In this paper, we investigate the effects of this polar gas on the X-ray spectrum of AGN using ray-tracing simulations. Two geometries for the polar gas are considered, (1) a hollow cone corresponding to the best fit MIR model and (2) a filled cone, both with varying column densities (ranging from cm) along with a torus surrounding the central X-ray source. We find that the polar gas leads to an increase in the equivalent width of several fluorescence lines below keV (e.g., O, Ne, Mg, Si). A filled geometry is unlikely for the polar component, as the X-ray spectra of many Type 1 AGN would show signatures of obscuration. We also consider extra emission from the narrow line region such as a scattered power-law with many photoionised lines from obscured AGNs, and different opening angles and matter compositions for the hollow cone. These simulations will provide a fundamental benchmark for current and future high spectral resolution X-ray instruments, such as those on board XRISM and Athena.

Accepted for publication on MNRAS

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