Evidence For Advective Flow From Multi-Wavelength Observations Of Nova Muscae

Abstract

We model the UV/optical spectrum of the black hole binary Nova Muscae as a sum of black body emissions from the outer region of an accretion disk. We show for self-consistency that scattering effects in this region are not important. The black hole mass ($M\approx 6M_{\odot }$), the inclination angle ($\mu \approx 0.5$) and the distance to the source ($D\approx 5$ kpc) have been constrained by optical observations during quiescence (Orosz et al. 1996). Using these values we find that the accretion rate during the peak was $\dot{M}\approx 8\times 10^{19}$ g sec${}^{-1}$ and subsequently decayed exponentially. We define a radiative fraction ($f$) to be the ratio of the X-ray energy luminosity to the total gravitational power dissipated for a keplerian accretion disk. We find that $f\approx 0.1$ and remains nearly constant during the Ultra-soft and Soft spectral states. Thus for these states, the inner region of the accretion disk is advection dominated. $f$ probably increased to $\approx 0.5$ during the Hard state and finally decreased to $\approx 0.03$ as the source returned to quiescence.

5 figures. uses aasms4.sty, accepted by ApJ

References in corpus (2)

• Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991
• Spectral Properties of Accretion Disks Around Black Holes II -- Sub-Keplerian Flows With and Without Shocks

Cited by in corpus (4)

• The Optical and Ultraviolet Spectral Energy Distributions of Short Period Black Hole X-ray Transients in Outburst
• Infrared Observations of Nova Muscae 1991: Black Hole Mass Determination from Ellipsoidal Variations
• Observations of the quiescent X-ray transients GRS 1124-684 (=GU Mus) and Cen X-4 (=V822 Cen) taken with ULTRACAM on the VLT
• Hydrodynamical winds from two-temperature plasma in X-ray binaries