Relativistic spectroscopy of the extreme NLS1 IRAS13224-3809

TL;DR

This study analyzes the extreme variability of NLS1 galaxy IRAS 13224-3809, revealing a relativistic reflection, an ultra-fast outflow, and complex spectral and flux correlations through a comprehensive X-ray observational campaign.

Contribution

It provides the first detection of a 0.24c ultra-fast outflow and explores the non-linear RMS-flux relation in an accreting AGN, advancing understanding of disk winds and relativistic effects.

Findings

Detection of a 0.24c ultra-fast outflow.

Observation of a non-linear RMS-flux relation.

Correlations between outflow properties and source flux.

Abstract

The narrow line Seyfert 1 (NLS1) IRAS 13224-3809 is the most X-ray variable active galactic nucleus (AGN), exhibiting 0.3-10 keV flux changes of over an order of magnitude within an hour. We report on the results of the 1.5 Ms 2016 XMM-Newton/NuSTAR observing campaign, which revealed the presence of a 0.24c ultra-fast outflow in addition to the well-known strong relativistic reflection. We also summarise other key results of the campaign, such as the first detection of a non-linear RMS-flux relation in an accreting source, correlations between outflow absorption strength/velocity and source flux, and a disconnect between the X-ray and UV emission. Our results are consistent with a scenario where a disk wind is launched close to the black hole, imprinting absorption features into the spectrum and variability.