An intermediate black hole spin in the NLS1 galaxy SWIFT J2127.4+5654: chaotic accretion or spin energy extraction?

Understand

We have observed the hard X-ray selected Narrow-Line Seyfert 1 galaxy SWIFT J2127.4+5654 with Suzaku.

• We report the detection of a broad relativistic iron emission line from the inner accretion disc.
• By assuming that the inner edge of the accretion disc corresponds to the innermost stable circular orbit of the black hole spacetime, the line profile enables us to measure a black hole spin a= 0.6\pm0.2.
• However, a non-rotating Schwarzschild spacetime is excluded at just above the 3 sigma level, while a maximally spinning Kerr black hole is excluded at the ~5 sigma level.