We review the physical origins for possible visible images of the supermassive black hole M87* in the galaxy M87 and SgrA* in the Milky Way Galaxy. The classical dark black hole shadow of the maximal size is visible in the case of luminous background behind the black hole at the distance exceeding the so-called photon spheres. The notably smaller dark shadow (dark silhouette) of the black hole event horizon is visible if the black hole is highlighted by the inner parts of the luminous accreting matter inside the photon spheres. The first image of the supermassive black hole M87*, obtained by the Event Horizon Telescope collaboration, shows the lensed dark image of the southern hemisphere of the black hole event horizon globe, highlighted by accreting matter, while the classical black hole shadow is invisible at all. A size of the dark spot on the Event Horizon Telescope (EHT) image agrees with a corresponding size of the dark event horizon silhouette in a thin accretion disk model in the case of either the high or moderate value of the black hole spin, $a\gtrsim 0.75$.

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黑洞M87 *和SgrA *的可见形状

我们回顾了银河系M87中超大质量黑洞M87 *和银河系SgrA *的可能可见图像的物理起源。在黑洞后面的发光背景超过所谓的光子球体的距离的情况下，可以看到最大尺寸的经典暗黑洞阴影。如果黑洞被光子球体内发光的吸积物质的内部突出显示，则黑洞事件视界的暗影（暗影）会明显减小。由事件地平线望远镜合作获得的超大质量黑洞M87 *的第一张图像显示了黑洞事件地平线地球仪南半球的镜头深色图像，通过增生物质突出显示，而经典黑洞阴影在此处看不见。所有。$\mathrm{一种}\gtrsim 0。75$。