LISA will detect gravitational waves (GWs) in the milli-Hz frequency band in space. Time-delay interferometry (TDI) is developed to suppress laser frequency noise beneath the acceleration noise and optical metrology noise. To identify stochastic GW signals, we need to characterize these noise components entangled in TDI data streams. In this work, we investigate noises characterization by combining the first-generation TDI channels from Michelson and Relay configurations. The Michelson channels are helpful to characterize acceleration noises in the lower frequency band, and the Relay configuration could effectively resolve optical path noises in the higher frequencies. Synergy could be achieved from their combination to determine these instrumental noises. Based on the characterized noises, we further reconstruct the power spectrum of noise in the selected TDI channel. Two cases are performed to characterize the spectrum shape of a stochastic GW signal. For a modeled signal, its parameter(s) could be directly estimated from the TDI data, and its spectrum could be recovered from the inferred values. And for an unexpected signal, its spectrum may be recognized and retrieved from noise-subtracted residual in which its power spectral density surpasses the noise level.

中文翻译：

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表征来自组合时延干涉仪的仪器噪声和随机引力波信号

LISA 将在太空中探测到毫赫兹频段的引力波（GW）。开发时延干涉仪 (TDI) 以抑制加速度噪声和光学计量噪声下的激光频率噪声。为了识别随机 GW 信号，我们需要表征这些纠缠在 TDI 数据流中的噪声分量。在这项工作中，我们通过结合来自 Michelson 和 Relay 配置的第一代 TDI 通道来研究噪声表征。迈克尔逊通道有助于表征较低频段的加速度噪声，而中继配置可以有效地解决较高频段的光路噪声。可以从它们的组合中获得协同作用，以确定这些乐器噪音。基于特征噪声，我们进一步重建了所选 TDI 通道中噪声的功率谱。执行两种情况来表征随机 GW 信号的频谱形状。对于建模信号，其参数可以直接从 TDI 数据估计，并且其频谱可以从推断值中恢复。对于意外信号，可以从其功率谱密度超过噪声水平的噪声减去残差中识别和检索其频谱。