AI 中文总结
本研究开发BipoSH分析方法，结合类Euclid星系巡天与类Simons天文台CMB重构的本动速度，可打破原初四极调制与各向异性星系偏置的简并，提升原初功率不对称性的检验精度。
AI 中文摘要
原初功率不对称性可探测统计各向同性的偏离，为原初宇宙的物理机制提供线索。本研究探讨如何利用星系巡天检验此类不对称性，并量化本动速度信息对这些检验的提升作用。我们开发了一套双极球谐函数（BipoSH）分析方法，用于分析星系密度与视线向本动速度的自功率谱及交叉功率谱，并结合类欧几里得（Euclid）光谱星系巡天，以及通过类西蒙斯天文台（Simons Observatory）的CMB地图经动力学Sunyaev-Zel'dovich效应重构的本动速度，开展费希尔预测。对于偶极不对称性，我们同时考虑与k^(-0.5)成比例的尺度无关调制和尺度依赖调制。在两种情况下，星系成团性均提供了大部分约束能力，而本动速度仅补充了适度的信息。对于四极不对称性，我们考虑了近期发现的各向异性星系偏置响应，并对其振幅进行边缘化处理。我们发现，仅依靠星系成团性会面临原初四极调制与各向异性星系偏置之间的简并问题，而加入本动速度信息可大幅打破该简并：密度-速度交叉功率谱提供了与星系自功率谱互补的信息，而速度自功率谱可独立于各向异性星系偏置约束原初调制。本动速度信息对更负的尺度依赖性愈发有效，对于与k^(-1)和k^(-2)成比例的尺度依赖性，其给出的约束比重子振荡光谱巡天（BOSS）的约束更严格。我们的结果表明，本动速度信息为利用大尺度结构检验原初功率不对称性提供了互补途径，尤其适用于存在各向异性星系偏置时的四极不对称性检验。
英文摘要
Primordial power asymmetry would probe departures from statistical isotropy, offering a clue to the physics of the primordial Universe. We investigate how such asymmetries can be tested with galaxy surveys and quantify how peculiar-velocity information can improve these tests. We develop a unified bipolar spherical harmonic (BipoSH) analysis of the auto- and cross-power spectra of galaxy density and line-of-sight peculiar velocity, and perform Fisher forecasts combining a Euclid-like spectroscopic galaxy survey with peculiar velocities reconstructed from Simons Observatory-like CMB maps through the kinetic Sunyaev-Zel'dovich effect. For dipolar asymmetry, we consider both scale-independent and scale-dependent modulations proportional to $k^{-0.5}$. Galaxy clustering provides most of the constraining power in both cases, while peculiar velocities add only modest information. For quadrupolar asymmetry, we account for the recently identified anisotropic galaxy-bias response and marginalize over its amplitude. We find that galaxy clustering alone suffers from a degeneracy between the primordial quadrupolar modulation and anisotropic galaxy bias. This degeneracy can be substantially broken by adding peculiar-velocity information: the density-velocity cross-spectrum provides complementary information to the galaxy auto-spectrum, while the velocity auto-spectrum constrains the primordial modulation independently of anisotropic galaxy bias. The velocity information becomes increasingly effective for more negative scale dependence, yielding constraints tighter than those from BOSS for scale dependences proportional to $k^{-1}$ and $k^{-2}$. Our results demonstrate that peculiar-velocity information provides a complementary avenue for testing primordial power asymmetry with large-scale structure, particularly for quadrupolar asymmetry in the presence of anisotropic galaxy bias.
Comments26 pages, 5 figures
