Probing the photoionised outflow in the NLS1 Ark 564: An XMM-Newton view

TL;DR

This study analyzes XMM-Newton X-ray data of Ark 564, revealing three low-velocity photoionised outflows that are likely located beyond 4 parsecs, with potential long-term effects on the host galaxy's interstellar medium.

Contribution

It provides the first detailed high-resolution X-ray spectral analysis of Ark 564's warm absorbers and constrains their location and impact on the galaxy.

Findings

Three warm absorbers with unusually low outflow velocities.

Absorbers located beyond 4 parsecs from the nucleus.

Potential long-term influence on the host galaxy's ISM.

Abstract

We present a detailed analysis of xmm X-ray observations of the Narrow line Seyfert-1 (NLS1) galaxy Ark 564 taken between 2000 and 2011. High-resolution X-ray spectroscopy is carried out on the resultant high signal-to-noise stacked spectrum. We find three separate photoionised warm absorbers outflowing at velocities unusually lower than typical NLS1s. Using recombination timescale estimates, improved constraints on the location of these clouds show they could be located beyond 4 pc from the central source. Our estimates of the outflow kinetics suggest that the AGN in Ark 564 is unlikely to affect the host galaxy in its current state but over typical lifetime of 10^7 years the ISM could be affected. The individual observations used here suggest the luminosity varies over weekly timescales and in addition we find evidence of gas response to changes in the ionising radiation.