The Spin of the Near‐Extreme Kerr Black Hole GRS 1915+105
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- 20 November 2006
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 652 (1), 518-539
- https://doi.org/10.1086/508457
Abstract
Based on a spectral analysis of the X-ray continuum that employs a fully relativistic accretion-disk model, we conclude that the compact primary of the binary X-ray source GRS 1915+105 is a rapidly-rotating Kerr black hole. We find a lower limit on the dimensionless spin parameter of a* greater than 0.98. Our result is robust in the sense that it is independent of the details of the data analysis and insensitive to the uncertainties in the mass and distance of the black hole. Furthermore, our accretion-disk model includes an advanced treatment of spectral hardening. Our data selection relies on a rigorous and quantitative definition of the thermal state of black hole binaries, which we used to screen all of the available RXTE and ASCA data for the thermal state of GRS 1915+105. In addition, we focus on those data for which the accretion disk luminosity is less than 30% of the Eddington luminosity. We argue that these low-luminosity data are most appropriate for the thin alpha-disk model that we employ. We assume that there is zero torque at the inner edge of the disk, as is likely when the disk is thin, although we show that the presence of a significant torque does not affect our results. Our model and the model of the relativistic jets observed for this source constrain the distance and black hole mass and could thus be tested by determining a VLBA parallax distance and improving the measurement of the mass function. Finally, we comment on the significance of our results for relativistic-jet and core-collapse models, and for the detection of gravitational waves.Comment: 58 pages, 18 figures. Accepted for publication in ApJ. New in this version is a proposed observational test of our spin model and the kinematic model of the radio jetKeywords
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This publication has 79 references indexed in Scilit:
- Spinning-black-hole binaries: The orbital hang-upPhysical Review D, 2006
- Spectral and Timing Evolution of the Black Hole X‐Ray Nova 4U 1543−47 during Its 2002 OutburstThe Astrophysical Journal, 2004
- Geometrically Thin Disk Accreting into a Black HoleThe Astrophysical Journal, 2003
- Evolution of magnetic fields around a Kerr black holePhysical Review D, 2003
- New light on the X-ray spectrum of the Crab NebulaAstronomy & Astrophysics, 2001
- Small‐Scale Structure in Galactic HiAbsorption toward GRS 1915+105The Astrophysical Journal, 2000
- Efficiency of Magnetized Thin Accretion Disks in the Kerr MetricThe Astrophysical Journal, 1999
- Magnetized Accretion inside the Marginally Stable Orbit around a Black HoleThe Astrophysical Journal, 1999
- Gamma-ray bursts from stellar mass accretion disks around black holesThe Astrophysical Journal, 1993
- Polarization features of X-ray radiation emitted near black holesThe Astrophysical Journal, 1980