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arXiv 2302.06140gr-qcastro-ph.HE
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黑洞阴影是无毛定理的可靠检验吗?

Is a black hole shadow a reliable test of the no-hair theorem?

Kostas Glampedakis, George Pappas

摘要:

捕捉被照亮的黑洞的事件视界投射的阴影的图像,在最基本的层面上,是一个在强烈弯曲的时空中极端光偏转的实验。因此,成像阴影的性质可以用来探测天体物理学黑洞的广义相对论克尔性质。作为这一前景的一个例子,人们通常断言,阴影可以检验该理论著名的黑洞质量和自旋多极矩的“无毛定理”的有效性。在本文中,我们评估这一说法通过计算的阴影的赤道半径在时空中的任意多极结构和慢旋转近似。我们发现,当考虑到高于四极矩的时刻,阴影获得高度的退化作为从克尔多极矩的偏差的函数。我们的分析结果表明,具有强非克尔多极结构的暗物体仍然可以产生具有特征性准圆形形状的克尔状阴影。

英文摘要:

Capturing the image of the shadow cast by the event horizon of an illuminated black hole is, at the most basic level, an experiment of extreme light deflection in a strongly curved spacetime. As such, the properties of an imaged shadow can be used to probe the general relativistic Kerr nature of astrophysical black holes. As an example of this prospect, it is commonly asserted that a shadow can test the validity of the theory's famous `no hair theorem' for the black hole's mass and spin multipole moments. In this paper, we assess this statement by calculating the shadow's equatorial radius in spacetimes with an arbitrary multipolar structure and within a slow rotation approximation. We find that when moments higher than the quadrupole are taken into account, the shadow acquires a high degree of degeneracy as a function of the deviation from the Kerr multipole moments. The results of our analysis suggest that dark objects with strongly non-Kerr multipolar structure could nevertheless produce a Kerr-like shadow with its characteristic quasi-circular shape.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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