Emergent Spectra From Disks Surrounding Kerr Black Holes: Effect of Photon Trapping and Disk Self-Shadowing
by Li, Guang-Xing and Yuan, Ye-Fei and Cao, Xinwu
15 pages, 13 figures
Based on a new estimation of their thickness, the global properties of relativistic slim accretion disks are investigated in this work. The resulting emergent spectra are calculated using relativistic ray-tracing method. The angular dependence of the disk luminosity, the effects of the heat advection and the effect of disk thickness on the estimation of the black hole spin and accretion rate are discussed. The improvements compared to previous works are that we use self-consistent disk equations and we consider the disk self-shadowing effect. We find that at moderate accretion rate, with inclusion of the heat advection effect, radiation trapped in the outer region of the accretion disks will escape in the inner region of the accretion disk and contribute to the emergent spectra. At high accretion rate, large inclination and large black hole spin, both the disk thickness and the heat advection have significant influence on the emergent spectra. Consequently, these effects will influence the measurement of the black hole spin based on the spectral fitting and influence the angular dependence of luminosity.