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| Paper: |
3-D Radiative Properties of Hot Accretion Flows onto the
Galactic Center Black Hole |
| Volume: |
439, The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies |
| Page: |
368 |
| Authors: |
Kato, Y. |
| Abstract: |
By solving radiative transfer equations (Kato et al. 2009), we examine
three-dimensional radiative properties of magnetohydrodynamic (MHD)
accretion flows confronting with the observed spectrum of Sgr A*, in
the vicinity of supermassive black hole at the Galactic center.
Models of magnetized accretion flows we used here are identical to
that of Kato (2004) which report quasi-periodic oscillations (QPOs).
We find that the core of radio emission is larger than the size of the
event horizon shadow and its peak location is shifted from the
gravitational center. The self-absorbed synchrotron emission by the
superposition of thermal electrons within a few tens of the
Schwarzschild radius can account for low-frequency spectra below the
critical frequency approximately 1012 Hz. Above the critical
frequency, the synchrotron self-Compton emission by thermal electrons
can account for variable emissions in recent near-infrared
observations. The X-ray spectra by Bremsstrahlung emission of thermal
electrons for the different mass accretion rates can be consistent
with both the flaring state and the quiescent state of Sgr A* observed
by Chandra. We will discuss a possible origin of QPOs in Sgr A* and
its spin in the context of disk seismology by using recently detected
QPOs. |
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