THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS

Dexter, Jason; Agol, Eric; Fragile, P Chris

doi:10.1088/0004-637X/717/2/1092

Title: THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS

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Abstract

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{sup 0} 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{sup o+35o}{sub -15}{sup o}, {xi}=-23{sup o+97o}{sub -22}{sup o}, T{sub e} = (5.4 {+-} 3.0) x 10{sup 10} K, and M-dot =5{sup +15}{sub -2}x10{sup -9} M{sub sun} yr{sup -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 atmore »« less

Authors:

Dexter, Jason ^[1]; Agol, Eric ^[2]; Fragile, P Chris ^[3]

Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States)
Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)
Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States)

Publication Date:: Sat Jul 10 00:00:00 EDT 2010

OSTI Identifier:: 21455199

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal

Additional Journal Information:: Journal Volume: 717; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/717/2/1092; Journal ID: ISSN 0004-637X

Country of Publication:: United States

Language:: English

Subject:: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; CRITICAL FREQUENCY; ELECTRON TEMPERATURE; FLARING; GALAXIES; GALAXY NUCLEI; INCLINATION; INTERFEROMETRY; MAGNETOHYDRODYNAMICS; MONOCHROMATIC RADIATION; RELATIVISTIC RANGE; SIMULATION; THREE-DIMENSIONAL CALCULATIONS; TURBULENCE; ELECTROMAGNETIC RADIATION; ENERGY RANGE; FLUID MECHANICS; HYDRODYNAMICS; MECHANICS; RADIATIONS

Citation Formats


                    Dexter, Jason, Agol, Eric, Fragile, P Chris, and McKinney, Jonathan C., E-mail: jdexter@u.washington.ed. THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS.  United States: N. p., 2010. 
        Web.  doi:10.1088/0004-637X/717/2/1092.

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                    Dexter, Jason, Agol, Eric, Fragile, P Chris, & McKinney, Jonathan C., E-mail: jdexter@u.washington.ed. THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS.  United States.  https://doi.org/10.1088/0004-637X/717/2/1092

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                    Dexter, Jason, Agol, Eric, Fragile, P Chris, and McKinney, Jonathan C., E-mail: jdexter@u.washington.ed. 2010.  
        "THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS".  United States.  https://doi.org/10.1088/0004-637X/717/2/1092.

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@article{osti_21455199,

  title        = {THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS},

  author       = {Dexter, Jason and Agol, Eric and Fragile, P Chris and McKinney, Jonathan C., E-mail: jdexter@u.washington.ed},

  abstractNote = {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{sup 0} 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{sup o+35o}{sub -15}{sup o}, {xi}=-23{sup o+97o}{sub -22}{sup o}, T{sub e} = (5.4 {+-} 3.0) x 10{sup 10} K, and M-dot =5{sup +15}{sub -2}x10{sup -9} M{sub sun} yr{sup -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} {sub c} {approx} 1-20, where {nu} {sub c} is the critical frequency for thermal synchrotron emission.},

  doi          = {10.1088/0004-637X/717/2/1092},

  url          = {https://www.osti.gov/biblio/21455199},
  journal      = {Astrophysical Journal},

  issn         = {0004-637X},

  number       = 2,

  volume       = 717,

  place        = {United States},

  year         = {Sat Jul 10 00:00:00 EDT 2010},

  month        = {Sat Jul 10 00:00:00 EDT 2010}

}

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