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.

We use 13 yr of Swift/BAT observations to probe the nature and origin of the hard X-ray (14–195 KeV) emission in Centaurus A. Since the beginning of the Swift operation in 2004, significant X-ray variability in the 14–195 KeV band has been detected, with mild changes in the source spectrum. Spectral variations became more eminent after 2013, following a softer-when-brighter trend. Using the power spectral density (PSD) method, we find that the observed hard X-ray photon flux variations are consistent with a red-noise process of slope, −1.3, with no evidence for a break in the PSD. We find a significant correlation between the hard X-ray and 230 GHz radio flux variations, with no time delay longer than 30 days. The temporal and spectral analysis confirms that the X-ray emission generated by the accretion in the ADAF model is sub-dominant as compared with the emission arsiing from that produced by the inner regions of the radio jet.

We present results of X-ray spectral and time-domain variability analyses of 4 faint, ‘quiescent’ blazars from the Swift-BAT 105-month catalog. We use observations from a recent, 5-month long NICER campaign, as well as archival BAT data. Variations in the 0.3-2 keV flux are detected on minute, ∼weekly, and monthly timescales, but we find that the fractional variability Fvar on these timescales is <25 per cent and decreases on longer timescales, implying generally low-amplitude variability across all sources and showing very low variability on monthly timescales ($F_{\rm var}\lesssim 13{{\%}}$), which is at odds with previous studies that show that blazars are highly variable in the X-rays on a wide range of timescales. Moreover, we find that the flux variability on very short timescales appears to be characterized by long periods of relative quiescence accompanied by occasional short bursts, against the relatively time-stationary nature of the variability of most other AGN light curves. Our analysis also shows that the broadband X-ray spectra (0.3-195 keV) of our sources can be described with different power law models. As is the case with most blazars, we find that 2 sources (2MASS J09343014-1721215 and PKS 0312-770) are well-modeled with a simple power law, while the remaining two (1RXS J225146.9-320614 and PKS 2126-15) exhibit curvature in the form of a log-parabolic power law. We also find that, in addition to the continuum, PKS 2126-15 requires significant absorption at the soft X-rays (≲1 keV) to fully describe the observed curvature, possibly due to absorption from the intergalactic medium.