NuSTAR measurement of the high spin of the supermassive black hole in NGC 4051
Abstract
We present the results of a NuSTAR campaign consisting of three 5 ks long observations of the AGN in NGC 4051, one of the local, bright AGN displaying the most extreme X-ray variability. The very hard >10 keV spectrum, with a strong 30 keV peak present even in the highest flux states, can be formally reproduced either by a reflection-dominated component, or by Compton-thick absorption of an intrinsic continuum at least an order of magnitude brighter than observed, or by a combination of the two. The absorption-only interpretation would imply a highly super-Eddington luminosity, and/or an X-ray dominated SED. The high relative flux of the reflected component in the other two cases requires an X-ray source within a few gravitational radii from a maximally rotating black hole.
- Publication:
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AAS/High Energy Astrophysics Division #14
- Pub Date:
- August 2014
- Bibcode:
- 2014HEAD...1410605R