Journal
ASTROPHYSICAL JOURNAL
Volume 717, Issue 2, Pages 1092-1104Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/717/2/1092
Keywords
accretion, accretion disks; black hole physics; Galaxy: center; radiative transfer; relativistic processes
Categories
Funding
- NSF [AST 0807385]
- NASA [05-ATP05-96, NNX08AX59H, PF7-80048]
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [0807385] Funding Source: National Science Foundation
- NASA [93580, NNX08AX59H] Funding Source: Federal RePORTER
Ask authors/readers for more resources
Recent high resolution observations of the Galactic center black hole allow for direct comparison with accretion disk simulations. We compare two-temperature synchrotron emission models from three-dimensional, general relativistic magnetohydrodynamic simulations to millimeter observations of Sgr A*. Fits to very long baseline interferometry and spectral index measurements disfavor the monochromatic face-on black hole shadow models from our previous work. Inclination angles <= 20 degrees are ruled out to 3 sigma. We estimate the inclination and position angles of the black hole, as well as the electron temperature of the accretion flow and the accretion rate, to be i = 50(-15 degrees)(+35 degrees), xi = -23(-22 degrees)(+97 degrees), T-e = (5.4 +/- 3.0) x 10(10) K, and (M) over dot = 5(-2)(+15) x 10(-9) M-circle dot yr(-1), respectively, with 90% confidence. The black hole shadow is unobscured in all best-fit models, and may be detected by observations on baselines between Chile and California, Arizona, or Mexico at 1.3 mm or .87 mm either through direct sampling of the visibility amplitude or using closure phase information. Millimeter flaring behavior consistent with the observations is present in all viable models and is caused by magnetic turbulence in the inner radii of the accretion flow. The variability at optically thin frequencies is strongly correlated with that in the accretion rate. The simulations provide a universal picture of the 1.3 mm emission region as a small region near the midplane in the inner radii of the accretion flow, which is roughly isothermal and has nu/nu(c) similar to 1-20, where nu(c) is the critical frequency for thermal synchrotron emission.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available