标题： 星系形状能告诉我们标准模型之外的物理什么信息？ 显示英文标题

标题： What can galaxy shapes tell us about physics beyond the standard model?

摘要： 星系的形状通过大尺度引力势来追踪晚期宇宙中的标量物理。 它们是否也对高自旋物理敏感？ 我们通过宇宙剪切及其更高阶推广（flexion）的统计，对早期和晚期宇宙中矢量和张量模式的观测结果进行了普遍研究。 高自旋贡献来自引力透镜效应和固有对齐，我们给出了每个贡献的最低阶相关器（其中一些之前已被推导），以及它们的平坦天空极限。 特别是，我们发现剪切谱$EB$和$BB$的非平凡来源取决于源的宇称性质。 我们考虑了两种矢量和张量模式的来源：尺度不变的原始涨落和宇宙弦，并预测了每种来源在即将进行的调查中的可探测性。 剪切被发现是一种强大的宇宙弦探针，主要是通过矢量模式的持续来源；而在非常小的尺度（$\ell\gtrsim 1000$）上，弯曲度对约束能力增加有限，但它可能是尚未知晓的三秩张量或晕尺度物理的有趣探针。 这些探针可以用来限制新物理理论，以解释最近脉冲星计时阵列观测的结果。 显示英文摘要

摘要： The shapes of galaxies trace scalar physics in the late-Universe through the large-scale gravitational potential. Are they also sensitive to higher-spin physics? We present a general study into the observational consequences of vector and tensor modes in the early and late Universe, through the statistics of cosmic shear and its higher-order generalization, flexion. Higher-spin contributions arise from both gravitational lensing and intrinsic alignments, and we give the leading-order correlators for each (some of which have been previously derived), in addition to their flat-sky limits. In particular, we find non-trivial sourcing of shear $EB$ and $BB$ spectra, depending on the parity properties of the source. We consider two sources of vector and tensor modes: scale-invariant primordial fluctuations and cosmic strings, forecasting the detectability of each for upcoming surveys. Shear is found to be a powerful probe of cosmic strings, primarily through the continual sourcing of vector modes; flexion adds little to the constraining power except on very small scales ($\ell\gtrsim 1000$), though it could be an intriguing probe of as-yet-unknown rank-three tensors or halo-scale physics. Such probes could be used to constrain new physics proposed to explain recent pulsar timing array observations.