RAY-RAMSES: a code for ray tracing on the fly in N-body simulations

Barreira, Alexandre; Llinares, Claudio; Bose, Sownak; Li, Baojiu

Abstract

We present a ray tracing code to compute integrated cosmological observables on the fly in AMR N-body simulations. Unlike conventional ray tracing techniques, our code takes full advantage of the time and spatial resolution attained by the N-body simulation by computing the integrals along the line of sight on a cell-by-cell basis through the AMR simulation grid. Moroever, since it runs on the fly in the N-body run, our code can produce maps of the desired observables without storing large (or any) amounts of data for post-processing. We implemented our routines in the RAMSES N-body code and tested the implementation using an example of weak lensing simulation. We analyse basic statistics of lensing convergence maps and find good agreement with semi-analytical methods. The ray tracing methodology presented here can be used in several cosmological analysis such as Sunyaev-Zel'dovich and integrated Sachs-Wolfe effect studies as well as modified gravity. Our code can also be used in cross-checks of the more conventional methods, which can be important in tests of theory systematics in preparation for upcoming large scale structure surveys.

Citation

Barreira, A., Llinares, C., Bose, S., & Li, B. (2016). RAY-RAMSES: a code for ray tracing on the fly in N-body simulations. Journal of Cosmology and Astroparticle Physics, 2016(05), Article 001. https://doi.org/10.1088/1475-7516/2016/05/001

• Journal Article Type: Article
• Acceptance Date: Apr 5, 2016
• Online Publication Date: May 3, 2016
• Publication Date: May 3, 2016
• Deposit Date: Aug 21, 2016
• Publicly Available Date: May 3, 2017
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2016
• Issue: 05
• Article Number: 001
• DOI: https://doi.org/10.1088/1475-7516/2016/05/001
• Public URL: https://durham-repository.worktribe.com/output/1376105
• Related Public URLs: http://arxiv.org/abs/1601.02012