Galaxy shapes have been observed to align with external tidal fields generated by the large-scale structures of the Universe. While the main source for these tidal fields is provided by long-wavelength density perturbations, tensor perturbations also contribute with a non-vanishing amplitude at linear order. We show that parity-breaking gravitational waves produced during inflation leave a distinctive imprint in the galaxy shape power spectrum which is not hampered by any scalar-induced tidal field. We also show that a certain class of tensor non-Gaussianities produced during inflation can leave a signature in the density-weighted galaxy shape power spectrum. We estimate the possibility of observing such imprints in future galaxy surveys.

中文翻译：

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来自星系内在排列的原始引力波

已经观察到星系形状与宇宙大尺度结构产生的外部潮汐场一致。虽然这些潮汐场的主要来源是由长波长密度扰动提供的，但张量扰动也有助于线性阶的非零振幅。我们表明，暴胀期间产生的破平引力波在星系形状功率谱中留下了独特的印记，不受任何标量引起的潮汐场的阻碍。我们还表明，暴胀期间产生的某一类张量非高斯性可以在密度加权的星系形状功率谱中留下特征。我们估计在未来的星系调查中观察到这种印记的可能性。