The Origin of X-ray Emission in the Gamma-ray emitting Narrow-Line Seyfert 1 1H 0323+342

TL;DR

This study analyzes X-ray data from the gamma-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342, revealing a soft excess, reflection features, and jet-related hard X-ray emission, with implications for accretion disk geometry.

Contribution

It provides the first detailed X-ray spectral and timing analysis of 1H 0323+342 using simultaneous XMM-Newton and NuSTAR observations, highlighting relativistic reflection and disk geometry deviations.

Findings

Relativistic reflection statistically required in the spectrum.

Inclination angle of 63 degrees, higher than radio observations suggest.

Flat emissivity profile indicating reflection from outer disk regions.

Abstract

We present the results of X-ray spectral and timing analyses of the closest gamma-ray emitting narrow-line Seyfert 1 ($\gamma$-NLS1) galaxy, 1H 0323+342. We use observations from a recent, simultaneous XMM-Newton/NuSTAR campaign. As in radio-quiet NLS1s, the spectrum reveals a soft excess at low energies ($\lesssim2$ keV) and reflection features such as a broad iron K emission line. We also find evidence of a hard excess at energies above $\sim35$ keV that is likely a consequence of jet emission. Our analysis shows that relativistic reflection is statistically required, and using a combination of models that includes the reflection model relxill for the broadband spectrum, we find an inclination of $i=63^{+7}_{-5}$ degrees, which is in tension with much lower values inferred by superluminal motion in radio observations. We also find a flat ($q=2.2\pm0.3$) emissivity profile, implying that there is more reflected flux than usual being emitted from the outer regions of the disk, which in turn suggests a deviation from the thin disk model assumption. We discuss possible reasons for this, such as reflection off of a thick accretion disk geometry.