Evolution of bimodal accretion flows
We consider time-dependent models for rotating accretion flows on to black holes, where a transition takes place from an outer cooling-dominated disc to a radiatively inefficient flow in the inner region. In order to allow for a transition of this type we solve the energy equation, both for the gas...
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| Vydáno v: | Monthly notices of the Royal Astronomical Society Ročník 344; číslo 2; s. 468 - 472 |
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| Hlavní autoři: | , , , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
Oxford, UK
Blackwell Science Ltd
11.09.2003
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| Témata: | |
| ISSN: | 0035-8711, 1365-2966 |
| On-line přístup: | Získat plný text |
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| Shrnutí: | We consider time-dependent models for rotating accretion flows on to black holes, where a transition takes place from an outer cooling-dominated disc to a radiatively inefficient flow in the inner region. In order to allow for a transition of this type we solve the energy equation, both for the gas and for the radiation field, including a radiative cooling flux and a turbulent convective heat flux directed along the negative entropy gradient. The transition region is found to be highly variable, and a corresponding variation is expected for the associated total luminosity. In particular, rapid oscillations of the transition radius are present on a time-scale comparable with the local Keplerian rotation time. These oscillations are accompanied by a quasi-periodic modulation of the mass flux at the outer edge of the advection-dominated accretion flow (ADAF). We speculate about the relevance for the high-frequency quasi-periodic oscillation phenomenon. |
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| Bibliografie: | istex:CF091B9DD000477CEF3EB0BD05DD7284CA158678 ark:/67375/HXZ-5GKZP4WV-B ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
| ISSN: | 0035-8711 1365-2966 |
| DOI: | 10.1046/j.1365-8711.2003.06832.x |