The nongravitational interactions of dark matter in colliding galaxy clusters

Harvey, D; Massey, R; Kitching, T; Taylor, A; Tittley, E

Abstract

Collisions between galaxy clusters provide a test of the nongravitational forces acting on dark matter. Dark matter’s lack of deceleration in the “bullet cluster” collision constrained its self-interaction cross section σDM/m < 1.25 square centimeters per gram (cm2/g) [68% confidence limit (CL)] (σDM, self-interaction cross section; m, unit mass of dark matter) for long-ranged forces. Using the Chandra and Hubble Space Telescopes, we have now observed 72 collisions, including both major and minor mergers. Combining these measurements statistically, we detect the existence of dark mass at 7.6σ significance. The position of the dark mass has remained closely aligned within 5.8 ± 8.2 kiloparsecs of associated stars, implying a self-interaction cross section σDM/m < 0.47 cm2/g (95% CL) and disfavoring some proposed extensions to the standard model.

Citation

Harvey, D., Massey, R., Kitching, T., Taylor, A., & Tittley, E. (2015). The nongravitational interactions of dark matter in colliding galaxy clusters. Science, 347(6229), 1462-1465. https://doi.org/10.1126/science.1261381

• Journal Article Type: Article
• Acceptance Date: Feb 12, 2015
• Online Publication Date: Mar 27, 2015
• Publication Date: Mar 27, 2015
• Deposit Date: Dec 10, 2014
• Publicly Available Date: Apr 10, 2015
• Journal: Science
• Print ISSN: 0036-8075
• Electronic ISSN: 1095-9203
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 347
• Issue: 6229
• Pages: 1462-1465
• DOI: https://doi.org/10.1126/science.1261381
• Public URL: https://durham-repository.worktribe.com/output/1449048
• Related Public URLs: https://arxiv.org/abs/1503.07675