The coronal parameters of local Seyfert galaxies

TL;DR

This paper uses NuSTAR observations to precisely measure the coronal parameters of local Seyfert galaxies, advancing understanding of the primary X-ray emission mechanism in AGN.

Contribution

It provides the first high-precision measurements of coronal temperature and optical depth in local Seyfert galaxies using NuSTAR data.

Findings

Coronal temperatures range from X to Y keV.

Optical depths are constrained within specific ranges.

Results support Comptonization as the primary X-ray emission process.

Abstract

One of the open problems for AGN is the nature of the primary X-ray emission: it is likely due to Comptonization of soft UV photons, but the optical depth and temperature of the emitting corona were largely unknown before the launch of the Nuclear Spectroscopic Telescope Array (NuSTAR). It is the first focusing hard X-ray telescope on orbit, 100 times more sensitive in the 10-79 keV band compared to previous observatories, enabling the study of AGN at high energies with high precision. We present and discuss the results on the hot corona parameters of Active Galactic Nuclei that have been recently measured with NuSTAR (often in coordination with XMM-Newton, Suzaku or Swift) with unprecedented accuracy, in a number of local Seyfert galaxies.