Reproducing Abell 2744 with the HyperMillennium Simulation

TL;DR

The Hyper Millennium simulation, one of the largest cosmological simulations, successfully reproduces the galaxy cluster Abell 2744, validating the DM model in extreme environments and demonstrating its capability to produce detailed galaxy and mass catalogues.

Contribution

This paper introduces the Hyper Millennium simulation with unprecedented scale and resolution, and demonstrates its ability to accurately reproduce a massive galaxy cluster in detail.

Findings

Excellent agreement in galaxy and mass density statistics at 0 kpc scale

Validation of DM model in extreme galaxy environments

Simulation coupled with semi-analytic models produces high-quality galaxy catalogues

Abstract

We present the Hyper Millennium (HM) simulation, an extremely large cosmological simulation designed to support next-generation galaxy surveys. The simulation follows 4.2 trillion dark matter particles in a comoving box of $2.5\ h^{-1}{\rm Gpc}$, with a mass resolution of $3.2 \times 10^8\, {h^{-1}\rm M_{\odot}}$ and a force resolution of $3.0\ h^{-1}{\rm kpc}$. Its combination of scale and resolution is ideal for studying large-scale structures and rare cosmic objects. In this first paper of the HM project, we explore whether the massive galaxy cluster Abell~2744 (A2744) can be reproduced in detail in the simulation. Pixel-based statistics of galaxy number density $N_{\rm gal}$, luminosity density $L_{\rm gal}$, and projected mass density $\kappa$ show excellent agreement between A2744 and its analogues down to $\sim 50$ kpc, once field-selection biases toward high galaxy surface density are accounted for. This concordance, achieved in one of the most extreme known galaxy environments, is a validation of the underlying $\Lambda{\rm CDM}$ model in the extreme regime of A2744. It also showcases the robustness and accuracy of the HM simulation, which, when coupled with a sophisticated semi-analytic galaxy formation model, is capable of producing galaxy and mass catalogues of comparable quality out to high redshift across its full comoving volume of 50.4 ${\rm Gpc^3}$.