Generating approximate halo catalogues for blind challenges in precision cosmology

Citation:

Garrison LH, Eisenstein DJ. Generating approximate halo catalogues for blind challenges in precision cosmology. Monthly Notices of the Royal Astronomical Society [Internet]. 2019;485 :2407-2416.

Date Published:

May 01, 2019

Abstract:

We present a method for generating suites of dark matter halo catalogueswith only a few N-body simulations, focusing on making small changes tothe underlying cosmology of a simulation with high precision. In thecontext of blind challenges, this allows us to re-use a simulation bygiving it a new cosmology after the original cosmology is revealed.Starting with full N-body realizations of an original cosmology and atarget cosmology, we fit a transfer function that displaces haloes inthe original so that the galaxy/HOD power spectrum matches that of thetarget cosmology. This measured transfer function can then be applied toa new realization of the original cosmology to create a new realizationof the target cosmology. For a 1 per cent change in σ8, weachieve 0.1 per cent accuracy to k = 1 h Mpc^{-1} in the real-spacepower spectrum; this degrades to 0.3 per cent when the transfer functionis applied to a new realization. We achieve similar accuracy in theredshift-space monopole and quadrupole. In all cases, the result isbetter than the sample variance of our 1.1 h^{-1} Gpc simulation boxes.

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