Oral Presentation

Probes of Dark Matter Using Large Halo Colliders

Author(s): M. James Jee (Yonsei/UC Davis)

Presenter: M. James Jee (Yonsei University/UC Davis)

Galaxy-mass offsets in cluster collisions were once considered a promising signal for assessing the self-interaction cross-section of dark matter. However, previous studies based on these offsets have been plagued by large measurement errors and general unknowns related to the merger phase and geometry. In this paper, we overcome these obstacles and present a robust constraint on the dark matter self-interaction cross-section using a new and potent method applied to ten cluster collisions hosting double radio relics. By utilizing the relic-relic distance relative to the halo-halo distance as an indicator of dark matter properties, we determined the self-interaction cross-section 68% upper limit to be <0.30 cm² g⁻¹. This represents the first robust result obtained from large halo colliders, incorporating marginalization over mass uncertainty, viewing angle, collision speed, merger phase, impact parameter, and gas slope.