The Extreme Spin of the Black Hole in Cygnus X-1

Details The Extreme Spin of the Black Hole in Cygnus X-1 The Extreme Spin of the Black Hole in Cygnus X-1

2011-06-18

arxiv.org/abs/1106.3690v2

Astronomy and Astrophysics

Astrophysics

High Energy Astrophysical Phenomena

Paper III of three papers on Cygnus X-1; 21 pages including 5 figures and 12 tables, ApJ in press. The paper is significantly

Scientific paper

The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and for the orbital inclination angle of the binary. Building on these results, which are based on our favored (asynchronous) dynamical model, we have measured the radius of the inner edge of the black hole's accretion disk by fitting its thermal continuum spectrum to a fully relativistic model of a thin accretion disk. Assuming that the spin axis of the black hole is aligned with the orbital angular momentum vector, we have determined that Cygnus X-1 contains a near-extreme Kerr black hole with a spin parameter a/M>0.95 (3\sigma). For a less probable (synchronous) dynamical model, we find a/M>0.92 (3\sigma). In our analysis, we include the uncertainties in black hole mass, orbital inclination angle and distance, and we also include the uncertainty in the calibration of the absolute flux via the Crab. These four sources of uncertainty totally dominate the error budget. The uncertainties introduced by the thin-disk model we employ are particularly small in this case given the extreme spin of the black hole and the disk's low luminosity.

Affiliated with

Also associated with

No associations

Rating

The Extreme Spin of the Black Hole in Cygnus X-1 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Extreme Spin of the Black Hole in Cygnus X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Extreme Spin of the Black Hole in Cygnus X-1 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-723008