Speaker
Description
In this work I aim to characterize the interplay between self-interacting dark matter (SIDM) models with velocity-dependent cross-section and the baryonic component inside galaxy clusters, investigating their combined effects on 3D and projected halo profile shapes and their deviation from collisionless dark matter (CDM) predictions. To this end, I investigate the DIANOGA-SIDM simulations of galaxy clusters featuring SIDM models with rare and frequent self-interactions as a result of, respectively, larger and smaller scattering angles. In particular, I employ a newly developed profiling and analysis pipeline to perform fitting and stacking of mass, density and velocity profiles, in order to compute statistically robust estimators of the SIDM effects across various halo mass scales. In general, I find that SIDM can consistently lower the central mass and density of low-mass halos inside dark-matter-only simulations, especially for frequent SIDM. However, while the inclusion of baryons suppresses this effect due to their clustering at low radii, the deviations from standard in this case are actually greater because CDM profiles exhibit a stronger central enhancement from baryons than their SIDM counterparts. Additionally, SIDM tends to isotropize the central particle velocity distribution leading to a lower velocity anisotropy profile than CDM at small radii, with boosted negative deviations in the rare SIDM model when introducing baryons. I further study global halo properties such as the concentration-mass relation and inner density profile slopes, and compare my theoretical predictions with the profiles of real galaxy clusters. Overall, this study will provide key theoretical predictions for comparison to ongoing and upcoming galaxy survey data, in order to distinguish between models of dark matter beyond $\Lambda$CDM.
| Parallel session | Astrophysical Probes of Dark Matter and Dark Energy |
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