The origin of X-ray emission in the gamma-ray emitting narrow-line Seyfert 1 1H 0323+342

Abstract

We present the results of X-ray spectral and timing analyses of the closest gamma-ray emitting narrow-line Seyfert 1 (γ-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 (≲2 keV) and reflection features such as a broad iron K emission line. We also find evidence of a hard excess at energies above ~35 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 broad-band 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 ± 0.3) emissivity profile, implying that there is more reflected flux than usual being emitted from the outer regions of the disc, which in turn suggests a deviation from the thin disc model assumption. We discuss possible reasons for this, such as reflection off of a thick accretion disc geometry.