论文标题
用丽莎探测随机重力波背景的各向异性
Probing Anisotropies of the Stochastic Gravitational Wave Background with LISA
论文作者
论文摘要
我们研究了激光干涉仪空间天线（LISA）对随机重力波背景（SGWB）各向异性的灵敏度。我们首先讨论SGWB的主要天体和宇宙学来源，其特征是GW能量密度的各向异性，并构建了一个信号到噪声估计量，以量化Lisa对不同多物体的敏感性。然后，我们对具有LISA的各向异性特征可检测性的前景进行了Fisher矩阵分析，该特征的可检测性用于单个多物体，重点是具有幂律频率轮廓的SGWB。我们考虑了丽莎检测器的特定扫描策略，计算噪声角光谱。我们分析了通过多普勒增强各向同性SGWB产生的运动学偶极子和四极杆的情况。我们发现$β\，ω_{\ rm gw} \ sim 2 \ times 10^{ - 11} $需要观察带有LISA的偶极信号。检测器对四极的响应具有一个因子$ \ sim 10^3 \，β$相对于偶极子。从理论的角度和地图制作的角度来看，各向异性的表征使我们能够提取可用于了解SGWB起源的信息，并区分不同叠加的SGWB源。
We investigate the sensitivity of the Laser Interferometer Space Antenna (LISA) to the anisotropies of the Stochastic Gravitational Wave Background (SGWB). We first discuss the main astrophysical and cosmological sources of SGWB which are characterized by anisotropies in the GW energy density, and we build a Signal-to-Noise estimator to quantify the sensitivity of LISA to different multipoles. We then perform a Fisher matrix analysis of the prospects of detectability of anisotropic features with LISA for individual multipoles, focusing on a SGWB with a power-law frequency profile. We compute the noise angular spectrum taking into account the specific scan strategy of the LISA detector. We analyze the case of the kinematic dipole and quadrupole generated by Doppler boosting an isotropic SGWB. We find that $β\, Ω_{\rm GW}\sim 2\times 10^{-11}$ is required to observe a dipolar signal with LISA. The detector response to the quadrupole has a factor $\sim 10^3 \,β$ relative to that of the dipole. The characterization of the anisotropies, both from a theoretical perspective and from a map-making point of view, allows us to extract information that can be used to understand the origin of the SGWB, and to discriminate among distinct superimposed SGWB sources.
