Structures And Spectra From Slim Disk And Slim Disk/Two-temperature Corona

Accretion onto black holes is of great signi?cance for understanding a variety ofactive phenomena in the universe, including stellar-mass black-hole candidates and ac-tive galactic nuclei. With the enormous advancements of astronomy observations, theaccretion disk theory has been developed into modern advection-dominated accretionparadigm. Studying the structures of and the emergent spectra from accretion disks,combining diverse observation data, will uncover the physics nature of the accretion?ows and the central bodies, and help to understand the formation and evolution ofblack holes, galaxies and even the universe. In this dissertation, we review the progressof accretion, especially of disk accretion theory. The outward transfer of angular mo-mentum and energy, the dissipation of gravitational energy through viscous processes,and the formation of accretion disks are described. The basic properties of accretiondisks in various celestial bodies are summarized. The standard disk model and someevidences of accretors with high accretion rates are introduced. We focus studies onslim disks, especially on the structures of and the emergent spectra from slim diskswith transition regions and slim/corona models. We have improved the treatment ofradiation deviated from black body in classical slim disks, built a uni?ed accretion diskmodel for any optical depth, and developed the accretion disk/corona theory with highmass accretion rates. A uni?ed disk model for any optical depth has been built with a bridged formulafor radiation. The improved slim disk models treat more accurately the modi?ed black-body radiation due to electron scattering effects in the inner disk regions, especiallyin the transition regions (τe? 1) with α > 0.01 and 1 < m ≤ 50. This extends ˙the parameter space (α, m, m) appropriate for slim disk studies. Our studies on global ˙structures of slim disks with transition regions include: 1) the effects of transition re-gions on disk solutions and S-shaped curves; 2) the relations of the transition regionradius with the accretion rate and viscosity parameter, which can be approximated byRtr = c1αpαmp1 exp(?c2mp2) with α > 0.01 and pα ～ 1; 3) the transition region ˙ ˙radii in stellar-mass black-hole accretion disks are larger than those in accretion diskslocated in galactic nuclei. But the modi?ed black-body radiation due to electron scat- – III –Abstractterings can not be ignored in either case. Considering the effects of electron's Thomsonscattering and Compton scattering, the emergent spectra calculated from global struc-tures of slim disks with transition regions, have not the problem that the energy ?uxes athigh frequencies are overestimated, which happens in classical slim disks. With a lowaccretion rate, the emergent spectra from slim disks can be approximated by multicolordisk spectra (MCD) with p = 0.75; while with a super-critical accretion rate, the spectrabroaden and ?atten, and the high energy end can saturate with the increasing accretionrate. If ?tting the X-ray spectra of 0.1-10 keV with MCD, 0.5 ≤ p ≤ 0.6 and Tin > 1keV for m = 10 and m > 1 have been found, which naturally explains the so-called ˙"too hot a disk" existing in some luminous black-hole candidates and ultra-luminouscompact X-ray sources. Slim disk/two-temperature corona model has been constructed, using the slimdisks with transition regions and the two-temperature ADAFs for the description ofthe coronae. Similarly as energy spectral calculations, the probability of inverse Comp-ton scattering is introduced in the energy coupling equation between the slim disk andthe corona, which make the structural and spectral calculations be selfconsistent. Thecorona structure relies little on the central mass. The electron's scattering...