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arXiv · 1303.0835

The impact of systematic uncertainties in N-body simulations on the precision cosmology from galaxy clustering: a halo model approach

Hao-Yi Wu·Dragan Huterer
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Abstract

Dark matter N-body simulations provide a powerful tool to model the clustering of galaxies and help interpret the results of galaxy redshift surveys. However, the galaxy properties predicted from N-body simulations are not necessarily representative of the observed galaxy populations; for example, theoretical uncertainties arise from the absence of baryons in N-body simulations. In this work, we assess how the uncertainties in N-body simulations impact the cosmological parameters inferred from galaxy redshift surveys. Applying the halo model framework, we find that the velocity bias of galaxies in modeling the redshift-space distortions is likely to be the predominant source of systematic bias. For a deep, wide survey like BigBOSS, current 10 per cent uncertainties in the velocity bias limit k_max to 0.14 h/Mpc. In contrast, we find that the uncertainties related to the density profiles and the galaxy occupation statistics lead to relatively insignificant systematic biases. Therefore, the ability to calibrate the velocity bias accurately -- from observations as well as simulations -- will likely set the ultimate limit on the smallest length scale that can be used to infer cosmological information from galaxy clustering.

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Hao-Yi Wu, Dragan Huterer. 2013-07-27. The impact of systematic uncertainties in N-body simulations on the precision cosmology from galaxy clustering: a halo model approach. https://doi.org/10.1093/mnras%2Fstt1200

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