DECIGO/BBO as a Probe to Constrain Alternative Theories of Gravity
DECIGO/BBO as a Probe to Constrain Alternative Theories of Gravity
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DOI：
10.1143/ptp.123.1069
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发表时间：
2009-08
影响因子：
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通讯作者：
Kent Yagi;Takahiro Tanaka
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文献类型：
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作者：
Kent Yagi;Takahiro Tanaka
我们计算了用DECIGO和BBO等DECIGO和BBO等分频引力波干涉仪对替代引力理论的约束程度。这里我们讨论了Brans-Dicke理论和质量引力子理论作为典型的例子。对于Brans-Dicke(BD)理论，我们考虑了由中子星(NS)和中等质量黑洞(IMBH)组成的致密双星的激发；对于大质量引力子理论，我们考虑了由超大质量黑洞(SMBH)和黑洞(SMBH)组成的致密双星的激发。使用包含自旋效应的受限2PN波形并考虑自旋进动，我们对$10^4$双星进行了蒙特卡罗模拟，以估计包括Brans-Dicke参数$\omega{\mathm{bd}}$和引力子康普顿长度$\lambda_g$在内的双星参数的确定精度。假设SNR=$\SQRT{200}$的$(1.4，10)M_{\ODOT}$NS/BH二元数，则对$\omega_{\mathm{bd}}$的约束为$\omega_{\mathm{bd}}>；2.32\x 10^6$，比LISA观测得到的估计约束强300倍。此外，我们发现，由于预期的较大的NS/BH双星合并率$O(10^4)$yr$-1}$，统计分析得到$omega_{\mathm{bd}}>；3.77\x 10^8$，这比目前从太阳系实验中得到的最强界限强4个数量级。对于大质量引力子理论，假设$(10^6，10^5)M_{ODOT}$BH/BH双星在3Gpc时，人们平均可以设置一个约束$\lambda_g>；3.35\x 10^{20}$cm。这比从太阳系实验中获得的要强三个数量级。从这些结果可以理解，DECIGO/BBO也是约束其他引力理论的一个非常强大的工具。
We calculate how strongly one can constrain the alternative theories of gravity with deci-Hz gravitational wave interferometers such as DECIGO and BBO. Here we discuss Brans-Dicke theory and massive graviton theories as typical examples. We consider the inspiral of compact binaries composed of a neutron star (NS) and an intermediate mass black hole (IMBH) for Brans-Dicke (BD) theory and those composed of a super massive black hole (SMBH) and a black hole (SMBH) for massive graviton theories. Using the restricted 2PN waveforms including spin effects and taking the spin precession into account, we perform the Monte Carlo simulations of $10^4$ binaries to estimate the determination accuracy of binary parameters including the Brans-Dicke parameter $\omega_{\mathrm{BD}}$ and the graviton Compton length $\lambda_g$. Assuming a $(1.4, 10)M_{\odot}$ NS/BH binary of SNR=$\sqrt{200}$, the constraint on $\omega_{\mathrm{BD}}$ is obtained as $\omega_{\mathrm{BD}}>2.32\times 10^6$, which is 300 times stronger than the estimated constraint from LISA observation. Furthermore, we find that, due to the expected large merger rate of NS/BH binaries of $O(10^4)$ yr$^{-1}$, a statistical analysis yields $\omega_{\mathrm{BD}}>3.77\times10^8$, which is 4 orders of magnitude stronger than the current strongest bound obtained from the solar system experiment. For massive graviton theories, assuming a $(10^6, 10^5)M_{\odot}$ BH/BH binary at 3Gpc, one can put a constraint $\lambda_g>3.35\times10^{20}$cm, on average. This is three orders of magnitude stronger than the one obtained from the solar system experiment. From these results, it is understood that DECIGO/BBO is a very powerful tool for constraining alternative theories of gravity, too.