A Few Properties of X-Ray Novae:
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A Few Properties of X-Ray Novae: Observed Low Frequency QPOs and Accretion Disk Structure Soon-Wook Kim (Korea Astronomy and Space Science Institute). Abstract.

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A Few Properties of X-Ray Novae:Observed Low Frequency QPOs and Accretion Disk StructureSoon-Wook Kim(Korea Astronomy and Space Science Institute)


We examine possible correlations of a few known observational physical parameters, such as orbital period, mass function and black hole mass, to the observed values of low frequency quasi-periodic oscillations (QPOs). The possible correlations are discussed on the context of the physics of accretion.

Black hole x ray binary parameters orbital period mass function and dynamical mass of black holes
Black Hole X-Ray Binary Parameters:Orbital Period, Mass Function and Dynamical Mass of Black Holes

  • These are 18 dynamically confirmed black holes (BHs), meaning that their mass function

    are known, where Mx and Mc are black hole and companion masses, Kc is the velocity amplitude of the companion star, Porb is the orbital period, and G is the gravitational constant.Among these sources, the nature of companions for two sources are unknown. In addition, the quasi-periodic oscillations (QPOs) at the lower frequencies of ~mHz up to ~30Hz are not available in 4 sources. We therefore examine 12 sources to find correlations among these parameters. In spite of the microquasar nature, Cygnus X-3 is excluded as a dynamically confirmed black hole.


Low frequency qpos vs orbital period
Low Frequency QPOs vs. Orbital Period

  • Closed and open circles represent shorter (~mHz) and longer (a few to ~30Hz ) QPO pairs for each sources. Reds are for microquasars.

  • In the long period BHs, the period of shorter QPOs become faster as orbital period increases.

  • Longer QPOs of 10-30Hz are almost independent of the orbital period.


Low frequency qpos vs mass function
Low Frequency QPOsvs. Mass Function

  • The mass functions are divided into two groups: smaller than ~3 or larger than ~5 solar masses.

  • No strong correlation can be found.

  • Symbols are the same as in the previous plot.


Low frequency qpos vs black hole mass
Low Frequency QPOs vs. Black Hole Mass

  • Black hole masses are concentrated on ~0.8-1.0 solar masses, except V404 Cygni (=GS/GRS 2023+338), larger than one solar mass.

  • No strong correlation can be found.

  • Symbols are the same as in the previous plot.


Qpos orbital period accretion disks
QPOs, Orbital Period & Accretion Disks

  • Orbital period is a strong function of the disk radius, and hence, of the inner disk edge (Rin) of the outer, thermal, geometrically thin, optically thick disk.

  • Rin is in turn a strong function of the inner mass accretion rate.

  • Therefore, the time-varying ~mHz QPOs could depend on the physics of the thermally unstable disks.

  • The detailed discussion can be found in Kim (2006), in preparation.

Conclusion: correlation of ~mHz QPOs to the orbital period ?