YITP WORKSHOP ON
Quasi-Periodic Oscillations and Time Variabilities of Accretion Flows
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ABSTRACT

NAME
INSTITUTE
TITLE OF THE TALK
J. Fukue
Osaka Kyoiku University, Japan
Relativistic Variable Eddington Factor
From the viewpoint of the comoving observer we have analytically examined the Eddington factor in the relativistic flow accelerating in the vertical direction; we have introduced the one-tau photo-oval observed by the comoving observer, and then calculated the comoving radiation fields and the Eddington factor.
The comoving radiation fields observed by the comoving observer becomes anisotropic, and the Eddington factor must deviate from the value for the isotropic radiation fields. We found that the Eddington factor depends on the velocity gradient as well as the flow velocity.
In the sufficiently optically thick linear regime, the Eddington factor is analytically expressed as $f (\tau, \beta, \frac{d\beta}{d\tau}) = \frac{1}{3} ( 1 + \frac{16}{15} \frac{d\beta}{d\tau})$, where $\tau$ is the optical depth and $\beta$ ($=v/c$) is the flow speed normalized by the speed of light.


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