# Nuclear spallation in active galaxies

## TL;DR

This paper revises nuclear spallation models in active galaxies, predicting detectable spectral signatures with upcoming high-resolution X-ray spectroscopy, especially if spallation occurs far from the black hole.

## Contribution

It recalculates Fe spallation reactions using improved cross sections and assesses detectability of spallation signatures with future high-resolution X-ray instruments.

## Key findings

- Differences in element abundances are detectable at large distances from black hole.
- Blurring effects hinder detection of spallation in the inner accretion disc.
- High-resolution spectroscopy can test spallation models in AGN environments.

## Abstract

A number of works point to the presence of narrow emission features at unusual energies in the X-ray spectra of active galactic nuclei (AGN) or to potentially low iron abundances as possible evidence for the spallation of iron. With the imminence of high-resolution calorimeter spectroscopy, the potential to test spallation models in astrophysical sources will soon be possible. Previously determined nuclear spallation reactions of Fe are recalculated making use of improved total inelastic and partial reaction cross sections that result in different absolute and relative abundances of the main spallation elements Mn, Cr, V, and Ti. The effects of ionisation and dynamics near the black hole are examined in simulated spectra with CCD and calorimeter (i.e. Hitomi) resolution. With high-resolution, differences in relative abundances and ionisation should be detectable if spallation is originating at large distances from the black hole (e.g. torus or disc wind) where blurring is not significant. If spallation were occurring in the inner accretion disc, it would likely be undetected as blurring effects would cause significant blending of spectral features.