Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Phys Rev Lett. 2010 Dec 17;105(25):251101. doi: 10.1103/PhysRevLett.105.251101. Epub 2010 Dec 13.
We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).
我们在 LISA 任务的背景下讨论了大质量黑洞双星合并产生的引力波的强引力透镜效应。多次探测将为竞争的引力理论、结构的演化和形成提供宝贵的信息，并且可能对 H0 和其他宇宙学参数施加限制。对于中间的大质量星系晕，引力透镜的大部分光深度都是由其提供的，而对于后者，波动光学效应可以忽略不计。对于广泛的形成历史，观察多个事件的概率都相当大。对于最乐观的模型，在一个 5 年的任务中，预计会有 ≲ 4 个信噪比≳8 的多重事件。即使是对于轻种子（≲ 60%）或重种子（≲ 40%）的保守模型，机会也很显著。由于引力透镜的放大作用，一些原本太微弱的信号也被放大到阈值以上（≲ 2 个/年）。
