Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons

Robertson, Andrew; Harvey, David; Massey, Richard; Eke, Vincent; McCarthy, Ian G.; Jauzac, Mathilde; Li, Baojiu; Schaye, Joop

Abstract

We present BAHAMAS-SIDM, the first large-volume, (400 h−1 Mpc)3, cosmological simulations including both self-interacting dark matter (SIDM) and baryonic physics. These simulations are important for two primary reasons: 1) they include the effects of baryons on the dark matter distribution 2) the baryon particles can be used to make mock observables that can be compared directly with observations. As is well known, SIDM haloes are systematically less dense in their centres, and rounder, than CDM haloes. Here we find that that these changes are not reflected in the distribution of gas or stars within galaxy clusters, or in their X-ray luminosities. However, gravitational lensing observables can discriminate between DM models, and we present a menu of tests that future surveys could use to measure the SIDM interaction strength. We ray-trace our simulated galaxy clusters to produce strong lensing maps. Including baryons boosts the lensing strength of clusters that produce no critical curves in SIDM-only simulations. Comparing the Einstein radii of our simulated clusters with those observed in the CLASH survey, we find that at velocities around 1000 km s−1 an SIDM cross-section of σ/m ≳ 1 cm2 g−1 is likely incompatible with observed cluster lensing.

Citation

Robertson, A., Harvey, D., Massey, R., Eke, V., McCarthy, I. G., Jauzac, M., Li, B., & Schaye, J. (2019). Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons. Monthly Notices of the Royal Astronomical Society, 488(3), 3646-3662. https://doi.org/10.1093/mnras/stz1815

• Journal Article Type: Article
• Acceptance Date: Oct 12, 2018
• Online Publication Date: Jul 10, 2019
• Publication Date: Sep 30, 2019
• Deposit Date: Dec 11, 2018
• Publicly Available Date: Jul 18, 2019
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 488
• Issue: 3
• Pages: 3646-3662
• DOI: https://doi.org/10.1093/mnras/stz1815
• Public URL: https://durham-repository.worktribe.com/output/1311919
• Related Public URLs: https://arxiv.org/abs/1810.05649