29 Quadruply Imaged Quasars Show Halo Densities Matching Gravothermal Core Collapse in Self-Interacting Dark Matter
Strong-lensing data from 29 quasars indicate dark matter halos undergoing gravothermal core collapse, supporting self-interacting models with 20-80 GeV particles and MeV mediators. The finding links lensing observables directly to dark-sector parameters while remaining consistent with cluster and satellite constraints. Future surveys can test the predicted cross-section range.
The study by Daniel Gilman and colleagues at the University of Toronto used strong gravitational lensing of 29 quadruply imaged quasars to infer central densities in dark matter halos. They modeled the systems with elastic Yukawa scattering and combined the lensing constraints with upper limits from galaxy clusters and Milky Way satellite evaporation. This approach isolates the velocity-dependent cross-section regime relevant to dwarf-galaxy scales.
Favored parameter space points to 20-80 GeV dark matter masses and mediator couplings near 10^{-3}, producing the rapid core collapse predicted by self-interacting dark matter but absent in cold dark matter simulations. The models also satisfy cosmological and direct-detection bounds by invoking a neutrinophilic scalar that decays invisibly. These results tighten the mapping between lensing observables and dark-sector microphysics.
Existing coverage understates the testable prediction: if core-collapse signatures appear in a larger sample at the same rate, standard cold dark matter must be modified or supplemented. Upcoming wide-field lensing surveys can falsify or confirm the cross-section range within five years.
A key limitation is the modest sample size and reliance on assumed lens modeling priors; larger, uniformly selected samples with JWST or Roman Space Telescope data would strengthen the statistical case.
Gilman et al.: Core-collapse signatures in >40% of a new sample of 100 quadruply imaged systems observed by 2029 would confirm the reported cross-section range at 3-sigma.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2610.40766)
- [2]Supporting Source(https://arxiv.org/abs/2305.03079)