Issue |
A&A
Volume 380, Number 2, December III 2001
|
|
---|---|---|
Page(s) | 739 - 744 | |
Section | Astronomical instrumentation | |
DOI | https://doi.org/10.1051/0004-6361:20011449 | |
Published online | 15 December 2001 |
The change from accretion via a thin disk to a coronal flow: Dependence on the viscosity of the hot gas
Max-Planck-Institut für Astrophysik, Karl- Schwarzschildstr. 1, 85740 Garching, Germany
Corresponding author: E. Meyer-Hofmeister, emm.mpa-garching.mpg.de
Received:
10
August
2001
Accepted:
8
October
2001
We study the transition from the geometrically thin disk to the hot coronal flow for accretion onto black holes. The efficiency of evaporation determines the truncation of the geometrically thin disk as a function of the black hole mass and the mass flow rate in the outer disk. The physics of the evaporation was already described in detail in earlier work (Meyer et al. [CITE]b). We show now that the value of the viscosity parameter for the coronal gas has a strong influence on the evaporation efficiency. For smaller values of the viscosity evaporation is less efficient. For a given mass flow rate from outside the geometrically thin disk then extends farther inward. Spectral transitions between soft and hard states are then expected for different mass flow rates in the outer disk. The physics is the same for the cases of stellar and supermassive black holes systems.
Key words: accretion, accretion disks / black hole physics / galaxies: nuclei / X-rays: galaxies
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.