# The Outer Rim Simulation: A Path to Many-Core Supercomputers

## TL;DR

The Outer Rim simulation is a large-scale, high-resolution cosmological N-body simulation designed to support large-scale structure surveys, utilizing many-core supercomputing to generate extensive data for cosmological analysis.

## Contribution

It presents one of the largest high-resolution N-body simulations on a many-core supercomputer, with new data products and analysis methods for cosmological surveys.

## Key findings

- Generated over 5PB of data for cosmological analysis
- Created synthetic catalogs for DESI, eBOSS, and LSST
- Demonstrated computational strategies for large-scale, high-resolution simulations

## Abstract

We describe the Outer Rim cosmological simulation, one of the largest high-resolution N-body simulations performed to date, aimed at promoting science to be carried out with large-scale structure surveys. The simulation covers a volume of (4.225Gpc)^3 and evolves more than one trillion particles. It was executed on Mira, a BlueGene/Q system at the Argonne Leadership Computing Facility. We discuss some of the computational challenges posed by a system like Mira, a many-core supercomputer, and how the simulation code, HACC, has been designed to overcome these challenges. We have carried out a large range of analyses on the simulation data and we report on the results as well as the data products that have been generated. The full data set generated by the simulation totals more than 5PB of data, making data curation and data handling a large challenge in of itself. The simulation results have been used to generate synthetic catalogs for large-scale structure surveys, including DESI and eBOSS, as well as CMB experiments. A detailed catalog for the LSST DESC data challenges has been created as well. We publicly release some of the Outer Rim halo catalogs, downsampled particle information, and lightcone data.