Rapid simulation rescaling from standard to modified gravity models

TL;DR

This paper presents a versatile algorithm for rescaling dark matter simulations from standard to modified gravity models, accurately reproducing power spectra and halo properties with minimal computational effort.

Contribution

The authors introduce a novel, generalizable rescaling method that accounts for scale-dependent growth and screening mechanisms in modified gravity models, extending previous approaches.

Findings

Power spectrum can be matched within 3% up to k=0.1h/Mpc.

Halo mass function and clustering are reproduced within 5%.

Method extends to higher k with halo internal structure adjustments.

Abstract

We develop and test an algorithm to rescale a simulated dark-matter particle distribution or halo catalogue from a standard gravity model to that of a modified gravity model. This method is based on that of Angulo & White but with some additional ingredients to account for (i) scale-dependent growth of linear density perturbations and (ii) screening mechanisms that are generic features of viable modified gravity models. We attempt to keep the method as general as possible, so that it may plausibly be applied to a wide range of modified theories, although tests against simulations are restricted to a subclass of $f(R)$ models at this stage. We show that rescaling allows the power spectrum of matter to be reproduced at the $\sim 3$ per cent level in both real and redshift space up to $k=0.1h\,\mathrm{Mpc}^{-1}$ if we change the box size and alter the particle displacement field; this limit can be extended to $k=1h\,\mathrm{Mpc}^{-1}$ if we additionally alter halo internal structure. We simultaneously develop an algorithm that can be applied directly to a halo catalogue, in which case the halo mass function and clustering can be reproduced at the $\sim 5$ per cent level. Finally we investigate the clustering of halo particle distributions, generated from rescaled halo catalogues, and find that a similar accuracy can be reached.