MEASURING MASS ACCRETION RATE ONTO THE SUPERMASSIVE BLACK HOLE IN M87 USING FARADAY ROTATION MEASURE WITH THE SUBMILLIMETER ARRAY
MEASURING MASS ACCRETION RATE ONTO THE SUPERMASSIVE BLACK HOLE IN M87 USING FARADAY ROTATION MEASURE WITH THE SUBMILLIMETER ARRAY
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DOI：
10.1088/2041-8205/783/2/l33
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发表时间：
2014-02
期刊：
影响因子：
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通讯作者：
C. Kuo;K. Asada;R. Rao;M. Nakamura;J. Algaba;H. Liu;M. Inoue;P. Koch;P. Ho;S. Matsushita-S.
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文献类型：
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作者：
C. Kuo;K. Asada;R. Rao;M. Nakamura;J. Algaba;H. Liu;M. Inoue;P. Koch;P. Ho;S. Matsushita-S.
我们提出了第一个约束的法拉第旋转措施（RM）在亚毫米波长的M87核。通过拟合亚毫米波阵列在大约230 GHz的四个独立频率下观测到的偏振位置角（χ），并将χ的变化解释为与吸积流相关的外部法拉第旋转的结果，我们确定M87核心的RM在−7.5 × 105和3.4 × 105 rad m−2之间。假设吸积流的密度分布遵循幂律分布，磁场是有序的、径向的、具有均分强度，RM的极限将质量吸积率限制在距离中心黑洞21史瓦西半径处的9.2 × 10−4 M/年以下。这个值是至少两个数量级小于邦迪吸积率，这表明吸积流的内部区域的吸积率显着抑制。因此，我们的结果不赞成经典的对流为主的吸积流和更喜欢绝热流入流出的解决方案或对流为主的吸积流的热吸积流在M87。
We present the first constraint on the Faraday rotation measure (RM) at submillimeter wavelengths for the nucleus of M87. By fitting the polarization position angles (χ) observed with the Submillimeter Array at four independent frequencies around ∼230 GHz and interpreting the change in χ as a result of external Faraday rotation associated with accretion flow, we determine the RM of the M87 core to be between −7.5 × 105 and 3.4 × 105 rad m−2. Assuming a density profile of the accretion flow that follows a power-law distribution and a magnetic field that is ordered, radial, and has equipartition strength, the limit on the RM constrains the mass accretion rate to be below 9.2 × 10−4 M☉ yr−1 at a distance of 21 Schwarzschild radii from the central black hole. This value is at least two orders of magnitude smaller than the Bondi accretion rate, suggesting significant suppression of the accretion rate in the inner region of the accretion flow. Consequently, our result disfavors the classical advection-dominated accretion flow and prefers the adiabatic inflow–outflow solution or convection-dominated accretion flow for the hot accretion flow in M87.