Testing the No-Hair Theorem with Observations of Black Holes in the Electromagnetic Spectrum
arXiv:1008.3902 · doi:10.1016/j.asr.2010.10.019
Abstract
According to the no-hair theorem, astrophysical black holes are uniquely described by their mass and spin. In this paper, we review a new framework for testing the no-hair hypothesis with observations in the electromagnetic spectrum. The approach is formulated in terms of a Kerr-like spacetime containing a quadrupole moment that is independent of both mass and spin. If the no-hair theorem is correct, then any deviation from the Kerr metric quadrupole has to be zero. We show how upcoming VLBI imaging observations of Sgr A* as well as spectroscopic observations of iron lines from accreting black holes with IXO may lead to the first astrophysical test of the no-hair theorem.
5 pages, 3 figures, to appear in Adv. Space Res., Proc. COSPAR 2010