Obtaining black hole solutions in alternative theories of gravity can be a difficult task due to cumbersome field equations that arise in many of such theories. In order to study the strong field regime in a model-free approach, one can consider deformed black hole solutions with additional parameters beyond mass, charge and angular momentum. We investigate the scattering and absorption of a massless scalar field by non-Schwarzschild black holes, considering the Johannsen and Psaltis parametrization. In particular, we study the scattering process by the classical (null geodesics analysis), semiclassical (glory approximation) and partial waves approaches. We present the formalism needed to compute the scattering and absorption of massless scalar waves by Schwarzschild-like black holes with a set of deformation parameters in addition to their mass and present a selection of our results. We compare our numerical results for the scattering cross section with the classical and semiclassical results, obtaining excellent agreement.

中文翻译：

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由变形的黑洞散射

由于许多此类理论中出现了繁琐的场方程，因此在替代引力理论中获得黑洞解可能是一项艰巨的任务。为了以无模型方法研究强场状态，可以考虑具有质量、电荷和角动量之外的附加参数的变形黑洞解决方案。考虑到 Johannsen 和 Psaltis 参数化，我们研究了非史瓦西黑洞对无质量标量场的散射和吸收。特别是，我们通过经典（零测地分析）、半经典（荣耀近似）和分波方法研究散射过程。我们提出了计算类 Schwarzschild 黑洞的无质量标量波的散射和吸收所需的形式，除了质量之外，还提供了一组变形参数，并提供了我们的结果选择。我们将散射截面的数值结果与经典和半经典结果进行比较，获得了极好的一致性。