Long XMM observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809: rapid variability, high spin and a soft lag. (arXiv:1208.5898v1 [astro-ph.HE])

Long XMM observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809: rapid variability, high spin and a soft lag. (arXiv:1208.5898v1 [astro-ph.HE]):
Results are presented from a 500ks long XMM-Newton observation of the
Narrow-Line Seyfert 1 galaxy IRAS13224-3809. The source is rapidly variable on
timescales down to a few 100s. The spectrum shows strong broad Fe-K and L
emission features which are interpreted as arising from reflection from the
inner parts of an accretion disc around a rapidly spinning black hole. Assuming
a power-law emissivity for the reflected flux and that the innermost radius
corresponds to the innermost stable circular orbit, the black hole spin is
measured to be 0.988 with a statistical precision better than one per cent.
Systematic uncertainties are discussed. A soft X-ray lag of 100s confirms this
scenario. The bulk of the power-law continuum source is located at a radius of
2-3 gravitational radii.