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arXiv 1209.0964gr-qcastro-ph.HE
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引力自作用力与最内层稳定圆轨道与光环间的有效单体形式

Gravitational self-force and the effective-one-body formalism between the innermost stable circular orbit and the light ring

Sarp Akcay, Leor Barack, Thibault Damour, Norichika Sago

摘要:

本文计算了质量为m_1的粒子沿最内层稳定圆轨道(ISCO)和质量为m_2>> m_1的史瓦西黑洞的光环之间的(不稳定)测地圆轨道运动时,作用在该粒子上的引力自作用力(GSF)的保守部分。更精确地说,我们构造了函数h_{uu}(x)= h_{μν} u ^μ u ^v(与德特韦勒规范不变的"红移"变量有关),其中h_{μν}是洛伦兹规范中的正则化度规微扰,u ^μ是m_1的四速度,x =[Gc ^{-3}(m_1 + m_2)Ω]^{2/3}是由轨道频率Ω构造的不变坐标。特别是,我们探讨的行为h_{uu}外的"光环"在x = 1/3,在那里的圆形轨道成为零。利用最近发现的h_{uu}和有效单体(EOB)形式主义的主径向势A(u,ν)中与对称质量比ν成线性关系的部分a(u)之间的联系,我们计算了整个区域0 <u <1/3上的a(u)。我们发现a(u)在光环处发散为~0.25(1 - 3u)^{-1/2},解释了这种发散的物理起源,并讨论了它对EOB形式主义的影响。我们构造了a(u)的精确的全局解析拟合,在整个区域0 <u <1/3(可能超过)上有效,并给出了a(u)及其在ISCO的前3阶导数的值的精确数值估计,以及ISCO频率的O(ν)偏移。在以前的工作中,我们使用GSF的数据在稍微偏心的轨道上计算a(u)和它的前两个导数的某种线性组合,还涉及第二EOB径向势{\bar D}(u,ν)的O(ν)部分\bar d(u)。将这些结果与我们目前的a(u)的整体解析表示相结合,我们数值计算了0 <u \leq 1/6上的{\bar d}(u)$。

英文摘要:

We compute the conservative piece of the gravitational self-force (GSF) acting on a particle of mass m_1 as it moves along an (unstable) circular geodesic orbit between the innermost stable circular orbit (ISCO) and the light ring of a Schwarzschild black hole of mass m_2>> m_1. More precisely, we construct the function h_{uu}(x) = h_{μν} u^μ u^ν (related to Detweiler's gauge-invariant "redshift" variable), where h_{μν} is the regularized metric perturbation in the Lorenz gauge, u^μ is the four-velocity of m_1, and x= [Gc^{-3}(m_1+m_2)Ω]^{2/3} is an invariant coordinate constructed from the orbital frequency Ω. In particular, we explore the behavior of h_{uu} just outside the "light ring" at x=1/3, where the circular orbit becomes null. Using the recently discovered link between h_{uu} and the piece a(u), linear in the symmetric mass ratio ν, of the main radial potential A(u,ν) of the Effective One Body (EOB) formalism, we compute a(u) over the entire domain 0<u<1/3. We find that a(u) diverges at the light-ring as ~0.25 (1-3u)^{-1/2}, explain the physical origin of this divergence, and discuss its consequences for the EOB formalism. We construct accurate global analytic fits for a(u), valid on the entire domain 0<u<1/3 (and possibly beyond), and give accurate numerical estimates of the values of a(u) and its first 3 derivatives at the ISCO, as well as the O(ν) shift in the ISCO frequency. In previous work we used GSF data on slightly eccentric orbits to compute a certain linear combination of a(u) and its first two derivatives, involving also the O(ν) piece \bar d(u) of a second EOB radial potential {\bar D}(u,ν). Combining these results with our present global analytic representation of a(u), we numerically compute {\bar d}(u)$ on the interval 0<u\leq 1/6.

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