Cosmological Remapping for Efficient Generation of 21 cm Intensity Mapping Mocks
Abstract
We present a novel application of cosmological rescaling, or "remapping," to generate 21 cm intensity mapping mocks for different cosmologies. The remapping method allows for computationally efficient generation of N-body catalogs by rescaling existing simulations. In this work, we employ the remapping method to construct dark matter halo catalogs, starting from the Horizon Run 4 simulation with WMAP5 cosmology, and apply it to different target cosmologies, including WMAP7, Planck18 and Chevallier-Polarski-Linder (CPL) models. These catalogs are then used to simulate 21 cm intensity maps. We use the halo occupation distribution (HOD) method to populate halos with neutral hydrogen (HI) and derive 21 cm brightness temperature maps. Our results demonstrate the effectiveness of the remapping approach in generating cosmological simulations for large-scale structure studies, offering an alternative for testing observational data pipelines and performing cosmological parameter forecasts without the need for computationally expensive full N-body simulations. We also analyze the precision and limitations of the remapping, in light of the rescaling parameters and , as well as the effects of the halo mass and box size thresholds.
Cite
@article{arxiv.2506.14588,
title = {Cosmological Remapping for Efficient Generation of 21 cm Intensity Mapping Mocks},
author = {Rahima Mokeddem and Bruno B. Bizarria and Jiajun Zhang and W. S. Hipólito-Ricaldi and Carlos Alexandre Wuensche and Elcio Abdalla and Filipe B. Abdalla and Amilcar R. Queiroz and Thyrso Villela and Bin Wang and Chang Feng and Edmar C. Gurjão and Alessandro Marins},
journal= {arXiv preprint arXiv:2506.14588},
year = {2025}
}