Geometrical Effect of Supercritical Accretion Flows: Observational Implications of Galactic Black-Hole Candidates and Ultraluminous X-Ray Sources

We investigate the dependence of the viewing angle in supercritical accretionflows and discuss the observational implications of galactic black-holecandidates and ultraluminous X-ray sources. When the mass accretion rateexceeds the critical rate, then the shape of the disk is geometrically thickdue to the enhanced radiation pressure. The model spectra of supercriticalaccretion flows strongly depend on the inclination angle. Because the outerdisk blocks the emission from the disk inner region for high inclination angle.We also find that the spectral properties of low-inclination angle and lowaccretion-rate disks are very similar to those of high-inclination and highaccretion rate disks. That is, if an object has a high inclination and highaccretion rate, such a system suffers from self-occultation and the spectrumwill be extremely soft. Therefore, we cannot discriminate these differencesfrom spectrum shapes only. Conversely, if we use the self-occultationproperties, we could constrain the inclination angle of the system. We suggestthat some observed high temperature ultraluminous X-ray sources have nearface-on geometry, i < 40, and Galactic black hole candidate, XTE J1550-564,possesses relatively high-inclination angles, i > 60.Comment: 13 pages, 6 figures, accepted for publication in PAS