Black hole hair from scalar dark matter
Black hole hair from scalar dark matter
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DOI：
10.1088/1475-7516/2019/06/038
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发表时间：
2019-04
影响因子：
6.4
通讯作者：
L. Hui;D. Kabat;Xinyu Li;Luca Santoni;S. S. Wong-S.
中科院分区：
文献类型：
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作者：
L. Hui;D. Kabat;Xinyu Li;Luca Santoni;S. S. Wong-S.
我们发现，被标量暗物质包围的黑洞会产生标量毛发。这是Jacobson[1]指出的一个现象的推广，即远离黑洞的具有非平凡时间依赖关系的最小耦合标量将赋予黑洞毛发。在我们的例子中，这种时间依赖关系源于具有非零质量的标量场的振荡。我们系统地研究了不同标量质量下黑洞周围的标量分布。在小质量极限下，标量场在大半径r处有1/r分量，与Jacobson的结果一致。在大质量极限下(康普顿波长为视界量级或更小)，标量场具有1/R3/4的轮廓，在视界附近产生堆积，而在中等质量出现特殊的结点。因此，黑洞周围的暗物质轮廓虽然难以测量，但包含了关于暗物质粒子质量的信息。作为应用，我们考虑了最近由事件视界望远镜拍摄到的位于M87中心的超大质量黑洞的情况。它的视界大小大约是一个质量为10−20 eV的标量粒子的康普顿波长。我们考虑了预期的接近地平线的标量堆积的含义，对于质量为10−20 eV或更低的模糊暗物质。
We show that a black hole surrounded by scalar dark matter develops scalar hair. This is the generalization of a phenomenon pointed out by Jacobson [1], that a minimally coupled scalar with a non-trivial time dependence far away from the black hole would endow the black hole with hair. In our case, the time dependence arises from the oscillation of a scalar field with a non-zero mass. We systematically explore the scalar profile around the black hole for different scalar masses. In the small mass limit, the scalar field has a 1/r component at large radius r, consistent with Jacobson's result. In the large mass limit (with the Compton wavelength of order of the horizon or smaller), the scalar field has a 1/r3/4 profile yielding a pile-up close to the horizon, while distinctive nodes occur for intermediate masses. Thus, the dark matter profile around a black hole, while challenging to measure, contains information about the dark matter particle mass. As an application, we consider the case of the supermassive black hole at the center of M87, recently imaged by the Event Horizon Telescope. Its horizon size is roughly the Compton wavelength of a scalar particle of mass 10−20 eV. We consider the implications of the expected scalar pile-up close to the horizon, for fuzzy dark matter at a mass of 10−20 eV or below.