Measuring the Spin of GRS 1915+105 with Relativistic Disk Reflection
Abstract
GRS 1915+105 harbors one of the most massive known stellar black holes in the Galaxy. In May 2007, we observed GRS 1915+105 for 117 ksec in the low/hard state using Suzaku. We collected and analyzed the data with the HXD/PIN and XIS cameras spanning the energy range from 2.3-55 keV. Fits to the spectra with simple models reveal strong disk reflection through an Fe K emission line and a Compton back-scattering hump. We report constraints on the spin parameter of the black hole in GRS 1915+105 using relativistic disk reflection models. The model for the soft X-ray spectrum (i.e. < 10 keV) suggests a/M = 0.56(2) and excludes zero spin at the 4 sigma level of confidence. The model for the full broadband spectrum suggests that the spin may be higher, a/M = 0.98(1) (1 sigma confidence), and again excludes zero spin at the 2 sigma level of confidence. We discuss these results in the context of other spin constraints and inner disk studies in GRS 1915+105.
Keywords
Cite
@article{arxiv.0909.5383,
title = {Measuring the Spin of GRS 1915+105 with Relativistic Disk Reflection},
author = {J. L. Blum and J. M. Miller and A. C. Fabian and M. C. Miller and J. Homan and M. van der Klis and E. M. Cackett and R. C. Reis},
journal= {arXiv preprint arXiv:0909.5383},
year = {2014}
}
Comments
Accepted for publication in ApJ