Imaging bright-spots in the accretion flow near the black hole horizon of Sgr A*
Imaging bright-spots in the accretion flow near the black hole horizon of Sgr A*
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DOI：
10.1111/j.1365-2966.2005.09458.x
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发表时间：
2005-06
影响因子：
4.8
通讯作者：
A. Broderick;Abraham Loeb Institute for Theory;Computation;Harvard University
中科院分区：
文献类型：
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作者：
A. Broderick;Abraham Loeb Institute for Theory;Computation;Harvard University
在不久的将来，可以用一个非常大的亚毫米望远镜基线阵列获得银河系中心黑洞视界附近的图像(SGR A*)。最近观测到的SgrA*发射的短期红外和X射线变异性表明，黑洞附近的吸积流是成团的或不稳定的。我们计算了旋转黑洞周围圆形轨道上致密发射区(亮点)的出现与轨道半径和取向的函数关系。我们发现，黑洞的质量和自转可以从它们在光斑图像上的一般特征以及在其观测到的通量和偏振的光曲线上提取出来。即使当SPOT图像被平滑到预期的∼20-μ作为未来亚毫米观测的分辨率时，强烈的场扭曲仍然是显著的。
Images from the vicinity of the black hole horizon at the Galactic centre (Sgr A*) could be obtained in the near future with a Very Large Baseline Array of submillimetre telescopes. The recently observed short-term infrared and X-ray variability of the emission from Sgr A* implies that the accretion flow near the black hole is clumpy or unsteady. We calculate the appearance of a compact emission region (bright-spot) in a circular orbit around a spinning black hole as a function of orbital radius and orientation. We find that the mass and spin of the black hole can be extracted from their generic signatures on the spot image as well as on the light curves of its observed flux and polarization. The strong field distortion remains notable even when the spot image is smoothed over the expected ∼20-μ as resolution of the future submillimetre observations.