Cosmological Simulations Featured Project: Large-scale simulations for synthetic sky maps

Strong lensing arc generated from the cluster-scale halo extracted from the Q Continuum simulation. Source and foreground galaxies are placed using galaxy images from the Hubble Ultra Deep Field. This image does not include noise, PSF convolution, and cluster galaxies for clarity, though these capabilities are part of the lensing pipeline, described in Li et al (in prep.).
Caption: 

Strong lensing arc generated from the cluster-scale halo extracted from the Q Continuum simulation. Source and foreground galaxies are placed using galaxy images from the Hubble Ultra Deep Field. This image does not include noise, PSF convolution, and cluster galaxies for clarity, though these capabilities are part of the lensing pipeline, described in Li et al (in prep.).

(Authors: Katrin Heitmann, Hal Finkel, Nicholas Frontiere, Adrian Pope, Salman Habib, Steve Rangel, Eve Kovacs, Nan Li, Chris Sewell)

Two major simulations, among the largest high-resolution simulations world-wide, have been finished and are currently being analysed and processed to create new synthetic sky catalogs for the LSST DESC collaboration. One of the simulations, called the Outer Rim simulation, covers a volume of 4225 Mpc on a side and evolved more than 1 trillion particles. This leads to a mass resolution of ~2.6x109 Msun. The simulation was carried out on the BG/Q system Mira, currently the 5th fastest machine in the world, located at the Argonne Leadership Computing Facility.

A second simulation, the Q Continuum simulation (described in detail in Heitmann et al., arXiv:1411.3396), covers a volume of 1300 Mpc on a side and evolved more than half a trillion particles, for a mass resolution of ~1.5x108 Msun. This simulation was carried out on Titan, a GPU-CPU system located at Oak Ridge Leadership Computing Facility which is currently the second fastest machine in the world. The simulation used almost 90% of the full machine to achieve the high mass resolution in a large cosmological volume.

We have stored 100 snapshots for each of the simulations starting at z=10. Halo and subhalo catalogs for all snapshots are currently being constructed as well as merger trees. The high resolution in mass, force, and time make these simulations ideal for using semi-analytic models for creating synthetic sky catalogs. In addition, we have started to build pipelines for strong lensing analysis and weak lensing cluster mass mapping. Once finalized and tested, the catalogs will be publicly released.

The simulations were carried out with HACC (Hardware/Hybrid Accelerated Cosmology Code). The code itself and some selected results from both simulations are shown in Habib et al. (arxiv:1410.2805). Computing time for the simulations was granted under the DOE INCITE program.