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NAM2012 - All Presentation Details

Record 264 of 756

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Can we really measure black hole spin, and does it really power relativistic jets?

Author: Daniel Plant

University of Southampton

Co-Authors: R.P.Fender (University of Southampton); M.Coriat (University of Southampton); G.Ponti (University of Southampton)

Session: HE3: Multi-wavelength observations of compact objects

Presentation type: Talk      14:30  Friday 30th 14:15-15:30 


Modelling the profile of relativistic broadened iron 6.4keV emission lines has become a prominent tool in the estimation of black hole spin. However in some cases this method directly contradicts the results from the other major technique, fitting of the accretion disc continuum.  This implies that the application of one or both of these models is unreliable. Additionally, the iron line method assumes that the accretion disc extends to the innermost stable circular orbit (ISCO), a conclusion which is still very much under debate for accretion at relatively low luminosities. It is regarded that in the very faint 'quiescent' state the disc has receded, but to what extent, and at which point this occurs in the evolution of the outburst, is yet to be established. We present a study of several black hole binary systems in the canonical 'hard' states, firstly to determine the accuracy in which reflection features can be used to determine black hole spin. Our results indicate that, in some cases without strong independent constraints, parameter degeneracies can significantly alter the inferred result. Finally we present a case study of the black hole GX339-4, which we show displays distinct evolution of the iron line as it reaches higher luminosities in the low/hard state. To this end we consider how the accretion disc transforms throughout an outburst, discussing the implications this has upon spin determination and the truncated disc model. We furthermore utilise quasi-simultaneous radio observations; understanding how the radio emission and iron line profile vary together will help us to reliably test if black hole spin really does power relativistic jets in black holes on all scales.

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