Evidence For Intrinsic Magnetic Moments in Black Hole Candidates

Stanley L. Robertson, Darryl J. Leiter

Published 2001-02-22, updated 2001-06-19Version 2

We present evidence that the power law part of the quiescent x-ray emissions of neutron stars in low mass x-ray binaries is magnetospheric in origin. It can be very accurately calculated from known rates of spin and magnetic moments determined from the the $\sim 10^{3 - 4}$ times brighter luminosity at the transition to the hard spectral state. This strongly suggests that the spectral state transition for neutron stars is a magnetospheric propeller effect. We test the hypothesis that the similar spectral state switches and quiescent power law emissions of the black hole candidates might also be magnetospheric effects. In the process we derive proposed magnetic moments and rates of spin for them and accurately predict their quiescent luminosities. This constitutes an observational test for the physical realization of event horizons and suggests that they may not be formed during the gravitational collapse of ordinary matter.