Quasinormal modes of black holes in Horndeski gravity
Quasinormal modes of black holes in Horndeski gravity
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DOI：
10.1103/physrevd.97.104047
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发表时间：
2018-04
影响因子：
5
通讯作者：
O. Tattersall;P. Ferreira
中科院分区：
文献类型：
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作者：
O. Tattersall;P. Ferreira
我们研究了Horndeski标量张量引力中广义相对论黑洞(即没有标量毛发的黑洞)的微扰。首先，我们推导了Schwarzschild黑洞情况下度规场和标量场的奇偶宇称微扰方程，并证明了从这样的系统发出的引力波包含通常广义相对论谱和新标量场谱的准简正模频率的混合，而新标量谱仅由两个自由参数表征。然后我们专门研究了Horndeski理论的子族，其中引力波在宇宙背景下以光速传播；这种理论的标量准正规模谱的特征是只有一个参数作为标量场的有效质量。给出了静态黑洞和慢转黑洞标量谱准简正模频率的解析表达式。在这两种情况下，用数值方法计算的准简正波与用解析方法计算的结果符合得很好。
We study the perturbations to General Relativistic black holes (i.e. those without scalar hair) in Horndeski scalar-tensor gravity. First, we derive the equations of odd and even parity perturbations of both the metric and scalar field in the case of a Schwarzschild black hole, and show that the gravitational waves emitted from such a system contain a mixture of quasi-normal mode frequencies from the usual General Relativistic spectrum and those from the new scalar field spectrum, with the new scalar spectrum characterised by just two free parameters. We then specialise to the sub-family of Horndeski theories in which gravitational waves propagate at the speed of light $c$ on cosmological backgrounds; the scalar quasi-normal mode spectrum of such theories is characterised by just a single parameter $\mu$ acting as an effective mass of the scalar field. Analytical expressions for the quasi-normal mode frequencies of the scalar spectrum in this sub-family of theories are provided for both static and slowly rotating black holes. In both regimes comparisons to quasi-normal modes calculated numerically show good agreement with those calculated analytically in this work.