Estimating the Parameters of Extended Gravity Theories with the Schwarzschild Precession of S2 Star
Estimating the Parameters of Extended Gravity Theories with the Schwarzschild Precession of S2 Star
复制标题
用S2星的史瓦西进动估计扩展引力理论的参数
作者：
D. Borka;V. Borka Jovanović;S. Capozziello;A. Zakharov;P. Jovanović
在简要回顾了前人关于恒星轨道对广义引力的约束的结果之后，我们在假设与广义相对论（GR）预言一致的前提下，讨论了S2星星的Schwarzschild轨道岁差。目前，S2星星轨道与GR的第一后牛顿近似非常吻合。特别是，凯克和VLT（重力）团队都宣称，S2星星轨道近心点附近的引力红移与第一后牛顿（pN）近似的理论估计相对应。2020年，引力合作组织探测到S2星星围绕银河系中心超大质量黑洞（SMBH）的轨道进动，并显示其接近GR预测。基于这一观测事实，我们用S2星星的史瓦西岁差估计了扩展引力理论的参数。利用上述方法，我们估计了一些扩展引力模型的轨道进动角，包括幂律f（R）、一般Yukawa修正、标量-张量引力和非局域引力理论，这些引力理论都是用度规和Palatini形式表示的。在这种情况下，我们假设引力场是球对称的，因此，引力的替代理论只能用几个参数来描述。具体地说，考虑到轨道岁差，我们估计的参数范围的扩展引力模型的轨道岁差是一样的GR。然后，我们比较这些结果与我们以前的结果，这是通过拟合的S2星星的轨道观测到的天体测量位置。在幂律f（R）、类Yukawa修正、标量-张量引力和非定域引力理论的情况下，我们得到了类似于GR的轨道进动。根据这些结果，该方法是计算银河系中心引力位参数的有用工具。
After giving a short overview of previous results on constraining of Extended Gravity by stellar orbits, we discuss the Schwarzschild orbital precession of S2 star assuming the congruence with predictions of General Relativity (GR). At the moment, the S2 star trajectory is remarkably fitted with the first post-Newtonian approximation of GR. In particular, both Keck and VLT (GRAVITY) teams declared that the gravitational redshift near its pericenter passage for the S2 star orbit corresponds to theoretical estimates found with the first post-Newtonian (pN) approximation. In 2020, the GRAVITY Collaboration detected the orbital precession of the S2 star around the supermassive black hole (SMBH) at the Galactic Center and showed that it is close to the GR prediction. Based on this observational fact, we evaluated parameters of the Extended Gravity theories with the Schwarzschild precession of the S2 star. Using the mentioned method, we estimate the orbital precession angles for some Extended Gravity models including power-law f(R), general Yukawa-like corrections, scalar–tensor gravity, and non-local gravity theories formulated in both metric and Palatini formalism. In this consideration, we assume that a gravitational field is spherically symmetric, therefore, alternative theories of gravity could be described only with a few parameters. Specifically, considering the orbital precession, we estimate the range of parameters of these Extended Gravity models for which the orbital precession is like in GR. Then we compare these results with our previous results, which were obtained by fitting the simulated orbits of S2 star to its observed astrometric positions. In case of power-law f(R), generic Yukawa-like correction, scalar–tensor gravity and non-local gravity theories, we were able to obtain a prograde orbital precession, like in GR. According to these results, the method is a useful tool to evaluate parameters of the gravitational potential at the Galactic Center.