black hole (Kato and Fukue 1980). Kyoto group, including Matsumoto Ryoji,
Okazaki Atsuo, Fukue Jun, and Kato Shoji, examined the characteristics of topological structure and stability of the transonic flows towards black holes, and further
the wave trapping nature of relativistic disks.
Standard disks were found to be unable to describe all types of accretion
phenomena around compact objects. Models of slim disks were thus developed in
the end of 1980s by Abramowicz group in Europe (Abramowicz et al. 1988).
Mineshige and Ohsuga group in Kyoto took much attention to this model in relation
to ultra-luminous X-ray sources (ULXs). Super-Eddington accretion flows and outflows (including jets) were extensively studied by their group (Ohsuga et al. 2005).
As another type of accretion flows, the advection-dominated accretion flows
(ADAFs) were extensively developed in 1990s by Narayan group in Harvard,
Abramowicz group in Europe and by Kato’s group in Japan (Mineshige and Kato
1996; Kato 2000). ADAFs were cooled by advection (heat captured by matter rather
than radiation), so that ADAFs were much less luminous than the standard models.
ADAFs were first proposed in 1977 as a model of Cyg X-1 by Ichimaru Setsuo
(Ichimaru 1977), but his priority had been forgotten in the major groups of accretion
disk community till a meeting at Lund in Sweden (or at Reykjavik in Iceland) in the
end of 1990s, where Roland Svensson pointed out priority of Ichimaru’s work.
Disks around the young proto-stars and galactic nuclei were also studies by
Uchida Yutaka and Shibata Kazunari in 1989–1990. They showed that, in every
case, magnetic field plays essential role in the formation of disks and jets (Uchida
et al. 1990; Shibata and Uchida 1989).
Hydrodynamical and radiation-hydrodynamical models of bipoloar jets, disk
winds and shocks have been examined in various aspects by Fukue Jun of Osaka
Kyoiku University (Fukue 1987, 1991) and his group in the 1990s.
7.10.3.2 Molecular Clouds and Star Formation
The average stellar mass is around one solar mass, whereas the mass of original
molecular cloud reaches as high as several thousand solar mass. In the formation of
stars, the molecular clouds must be fragmented by the effects of self-gravity in some
stage of evolution. Miyama Shoken and Eriguchi Yoshiharu accomplished a simulation for the fragmentation of isothermal sheet-like molecular clouds. The result of
simulation is shown in Fig. 7.46, where one may see that the initial perturbations
grow to form filamentary structure and stars are born from these dense filaments
(Miyama et al. 1989; Miyama and Eriguchi 1990).
7.10.3.3 Globular Clusters and Galaxies
In the context of N-body simulation, merging of binary globular clusters and
colliding spherical galaxies are the same problem.
7.10 Theoretical Astrophysics
237
Okazaki Atsuo, Fukue Jun, and Kato Shoji, examined the characteristics of topological structure and stability of the transonic flows towards black holes, and further
the wave trapping nature of relativistic disks.
Standard disks were found to be unable to describe all types of accretion
phenomena around compact objects. Models of slim disks were thus developed in
the end of 1980s by Abramowicz group in Europe (Abramowicz et al. 1988).
Mineshige and Ohsuga group in Kyoto took much attention to this model in relation
to ultra-luminous X-ray sources (ULXs). Super-Eddington accretion flows and outflows (including jets) were extensively studied by their group (Ohsuga et al. 2005).
As another type of accretion flows, the advection-dominated accretion flows
(ADAFs) were extensively developed in 1990s by Narayan group in Harvard,
Abramowicz group in Europe and by Kato’s group in Japan (Mineshige and Kato
1996; Kato 2000). ADAFs were cooled by advection (heat captured by matter rather
than radiation), so that ADAFs were much less luminous than the standard models.
ADAFs were first proposed in 1977 as a model of Cyg X-1 by Ichimaru Setsuo
(Ichimaru 1977), but his priority had been forgotten in the major groups of accretion
disk community till a meeting at Lund in Sweden (or at Reykjavik in Iceland) in the
end of 1990s, where Roland Svensson pointed out priority of Ichimaru’s work.
Disks around the young proto-stars and galactic nuclei were also studies by
Uchida Yutaka and Shibata Kazunari in 1989–1990. They showed that, in every
case, magnetic field plays essential role in the formation of disks and jets (Uchida
et al. 1990; Shibata and Uchida 1989).
Hydrodynamical and radiation-hydrodynamical models of bipoloar jets, disk
winds and shocks have been examined in various aspects by Fukue Jun of Osaka
Kyoiku University (Fukue 1987, 1991) and his group in the 1990s.
7.10.3.2 Molecular Clouds and Star Formation
The average stellar mass is around one solar mass, whereas the mass of original
molecular cloud reaches as high as several thousand solar mass. In the formation of
stars, the molecular clouds must be fragmented by the effects of self-gravity in some
stage of evolution. Miyama Shoken and Eriguchi Yoshiharu accomplished a simulation for the fragmentation of isothermal sheet-like molecular clouds. The result of
simulation is shown in Fig. 7.46, where one may see that the initial perturbations
grow to form filamentary structure and stars are born from these dense filaments
(Miyama et al. 1989; Miyama and Eriguchi 1990).
7.10.3.3 Globular Clusters and Galaxies
In the context of N-body simulation, merging of binary globular clusters and
colliding spherical galaxies are the same problem.
7.10 Theoretical Astrophysics
237