Reproducing Abell 2744 with the HyperMillennium Simulation

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 $2.5h^{-1}\mathrm{Gpc}$, with a mass resolution of $3.2\times 10^8{h}^{-1}{\mathrm{M}}_{\odot }$ and a force resolution of $3.0h^{-1}\mathrm{kpc}$. 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 $N_{\mathrm{gal}}$, luminosity density $L_{\mathrm{gal}}$, and projected mass density $\hat{I}º$ 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 $\hat{I}›\mathrm{CDM}$ 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 $\mathrm{Gp}{\mathrm{c}}^3$.

16 pages, 11 figures; Accepted by Monthly Notices of the Royal Astronomical Society