Quantification of the multi-streaming effect in Redshift Space Distortion

Yi Zheng; Pengjie Zhang; Minji Oh

doi:10.1088/1475-7516/2017/05/030

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arXiv · 1611.09075

Quantification of the multi-streaming effect in Redshift Space Distortion

Yi Zheng·Pengjie Zhang·Minji Oh

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Abstract

Both multi-streaming (random motion) and bulk motion cause the Finger-of-God (FoG) effect in redshift space distortion (RSD). We apply a direct measurement of the multi-streaming effect in RSD from simulations, proving that it induces an additional, non-negligible FoG damping to the redshift space density power spectrum. We show that, including the multi-streaming effect, the RSD modelling is significantly improved. We also provide a theoretical explanation based on halo model for the measured effect, including a fitting formula with one to two free parameters. The improved understanding of FoG helps break the $f\sigma_8-\sigma_v$ degeneracy in RSD cosmology, and has the potential of significantly improving cosmological constraints.

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Yi Zheng, Pengjie Zhang, Minji Oh. 2016-11-28. Quantification of the multi-streaming effect in Redshift Space Distortion. https://doi.org/10.1088/1475-7516/2017/05/030

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