Abstract

Estimates for the parameters of accretion plasma flows and the central black hole by comparing the MHD model numerical calculations with observations for the center of our Galaxy Sagittarius A* in the radio range are obtained. The accretion flow was modeled in terms of the distribution of a toroidal two-temperature electron-proton plasma. It is assumed that protons are heated due to viscous dissipation effects, and electrons lose energy due to synchrotron radiation. It is considered that the Coulomb interactions between protons and electrons are ineffective. Based on a comparison with observations of the spectral flux density and polarization (linear and circular) for a supermassive black hole in the source Sagittarius A*, the following restrictions were obtained: the rotation parameter (spin) of the black hole is equal to \(a \approx 0.6\), the electron temperature is a fraction \({{T}_{p}}{\text{/}}3 < {{T}_{e}} < {{T}_{p}}\) of the proton temperature, the observer is located at an angle \(i \approx 50^\circ \) to the rotation axis of the black hole, and the accretion rate is much less than the Eddington limit \(\dot {M} \sim {{10}^{{ - 8}}}{-} {{10}^{{ - 10}}}{{\dot {M}}_{{{\text{Edd}}}}}\). It was not possible to obtain restrictions on the magnetic field due to the small sample in the plasma parameter \(\beta = 2{{p}_{{{\text{gas}}}}}{\text{/}}{{p}_{{{\text{mag}}}}}\).

中文翻译：

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源射手座A *附近黑洞和等离子体参数的限制

摘要

通过将MHD模型的数值计算与我们在射电范围内对银河人马座A *中心的观测值进行比较，可以获得对积聚等离子体流和中心黑洞参数的估计。根据环形两温电子质子等离子体的分布对吸积流进行建模。假定质子由于粘性耗散效应而被加热，并且电子由于同步加速器辐射而损失能量。认为质子与电子之间的库仑相互作用无效。基于对射手座A中超大质量黑洞的光谱通量密度和极化（线性和圆形）观察结果的比较*，得到以下限制：黑洞的旋转参数（旋转）等于\（a \约0.6 \），电子温度为分数\（{{T} _ {p}} {\ text {/}} 3 <{{T} _ {e}} <{{T} _ {p}} \）的质子温度，观察者位于一个角度\（i \大约50 ^ \ circ \）到黑洞的旋转轴上，并且吸积率远小于爱丁顿极限\（\ dot {M} \ sim {{10} ^ {{-8}}} {-} {{10} ^ { {-10}}} {{\ dot {M}} _ {{{\ text {Edd}}}}}} \）。由于等离子参数\（\ beta = 2 {{p} _ {{{\ text {gas}}}}} {\ text {/}}中的小样本，因此无法获得对磁场的限制{{p} _ {{{\ text {mag}}}}} \）。