Studies of intrinsic alignment effects mostly focus on the correlations between shapes of galaxies with each other, or with the underlying density field of the large scale structure of the universe. Lately, the correlation between shapes of galaxies and the large-scale velocity field has been proposed as an additional probe of the large scale structure. We use a Fisher forecast to make a prediction for the detectability of this velocity-shape correlation with a combination of redshifts and shapes from the 4MOST+LSST surveys, and radial velocity reconstruction from the Simons Observatory. The signal-to-noise ratio for the velocity-shape (dipole) correlation is 23, relative to 44 for the galaxy density-shape (monopole) correlation and for a maximum wavenumber of $0.2\: \mathrm{Mpc^{-1}}$. Increasing signal-to-noise for higher values of the maximum wavenumbers (respectively, 56 and 69, for a maximum wavenumber of $1\: \mathrm{Mpc^{-1}}$) indicate potential gains in the nonlinear regime. Encouraged by these predictions, we discuss two possible applications for the velocity-shape correlation. Measuring the velocity-shape correlation could improve the mitigation of selection effects induced by intrinsic alignments on galaxy clustering. We also find that velocity-shape measurements could potentially aid in determining the scale-dependence of intrinsic alignments when multiple shape measurements of the same galaxies are provided.

中文翻译：

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大尺度速度场星系排列的检测与应用前景

内在排列效应的研究主要集中在星系形状之间的相互关系，或与宇宙大尺度结构的潜在密度场之间的相关性。最近，星系形状与大尺度速度场之间的相关性被提出作为大尺度结构的附加探测。我们使用 Fisher 预测，结合来自 4MOST+LSST 调查的红移和形状以及来自西蒙斯天文台的径向速度重建，对这种速度-形状相关性的可探测性进行预测。速度-形状（偶极子）相关的信噪比为 23，而星系密度-形状（单极）相关的信噪比为 44，最大波数为 $0.2\：\mathrm{Mpc^{-1} }$。增大最大波数值（分别为 56 和 69，最大波数为 $1\:\mathrm{Mpc^{-1}}$）的信噪比表明非线性区域的潜在增益。受这些预测的鼓舞，我们讨论了速度-形状相关性的两种可能应用。测量速度-形状相关性可以改善对星系团簇内在排列引起的选择效应的缓解。我们还发现，当提供相同星系的多个形状测量值时，速度形状测量值可能有助于确定内在对齐的尺度依赖性。我们讨论了速度-形状相关性的两种可能的应用。测量速度-形状相关性可以改善对星系团簇内在排列引起的选择效应的缓解。我们还发现，当提供相同星系的多个形状测量值时，速度形状测量值可能有助于确定内在对齐的尺度依赖性。我们讨论了速度-形状相关性的两种可能的应用。测量速度-形状相关性可以改善对星系团簇内在排列引起的选择效应的缓解。我们还发现，当提供相同星系的多个形状测量值时，速度形状测量值可能有助于确定内在对齐的尺度依赖性。