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arXiv · 1309.5875

A Long XMM-Newton Observation of An Extreme Narrow Line Seyfert 1: PG 1244+026

Chichuan Jin·Chris Done·Matthew Middleton·Martin Ward
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Abstract

We explore the origin of the strong soft X-ray excess in Narrow Line Seyfert 1 galaxies using spectral-timing information from a 120ks {\it XMM-Newton} observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true additional soft X-ray continuum component and strongly relativistically smeared reflection, but both models also require a separate soft blackbody component. This is most likely intrinsic emission from the disc extending into the lowest energy X-ray bandpass. The {\it RMS} spectra on short timescales (200-5000s) contain both (non-disk) soft excess and power law emission. However, the spectrum of the variability on these timescales correlated with the 4-10 keV lightcurve contains only the power law. Together these show that there is fast variability of the soft excess which is independent of the 4-10 keV variability. This is inconsistent with a single reflection component making the soft X-ray excess as this necessarily produces correlated variability in the 4-10 keV bandpass. Instead, the {\it RMS} and covariance spectra are consistent with an additional cool Comptonisation component which does not contribute to the spectrum above 2 keV.

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Chichuan Jin, Chris Done, Matthew Middleton, Martin Ward. 2013-09-23. A Long XMM-Newton Observation of An Extreme Narrow Line Seyfert 1: PG 1244+026. https://doi.org/10.1093/mnras%2Fstt1801

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