Initial Measurements of Black Hole Spin in GX 339-4 from Suzaku Spectroscopy

Authors

J. M. Miller, University of Michigan
C. S. Reynolds, University of Maryland
A. C. Fabian, University of Cambridge
E. M. Cackett, University of MichiganFollow
G. Miniutti, University of Cambridge
J. Raymond, Smithsonian Astrophysical Observatory
D. Steeghs, University of Warwick
R. Reis, University of Cambridge
J. Homan, MIT Kavli Institute for Astrophysics and Space Research

Document Type

Article

Abstract

We report on a deep Suzaku observation of the stellar-mass black hole GX 339-4 in outburst. A clear, strong, relativistically shaped iron emission line from the inner accretion disk is observed. The broadband disk reflection spectrum revealed is one of the most sensitive yet obtained from an accreting black hole. We fit the Suzaku spectra with a physically motivated disk reflection model, blurred by a new relativistic line function in which the black hole spin parameter is a variable. This procedure yielded a black hole spin parameter of a=0.89+/-0.04. Joint modeling of these Suzaku spectra and prior XMM-Newton spectra obtained in two different outburst phases yields a spin parameter of a=0.93+/-0.01. The degree of consistency between these results suggests that disk reflection models allow for spin measurements that are not strongly biased by scattering effects. We suggest that the best value of the black hole spin parameter is a=0.93+/-0.01 (statistical)+/-0.04 (systematic). Although preliminary, these results represent the first direct measurement of nonzero spin in a stellar-mass black hole using relativistic line modeling.

Disciplines

Cosmology, Relativity, and Gravity | Stars, Interstellar Medium and the Galaxy

Comments

NOTICE IN COMPLIANCE WITH PUBLISHER POLICY: ©2008, American Astronomical Society. Available at: doi:10.1086/589446

Recommended Citation

Initial Measurements of Black Hole Spin in GX 339–4 from Suzaku Spectroscopy

J. M. Miller et al. 2008 ApJ 679 L113