(Re)Assessing Galaxy Clusters with Cosmological Models: Scales, Anisotropies, and Scientific Explanation

Abstract Galaxy clusters are commonly used tracers of cosmology. Gravitational lensing analysis of the Bullet Cluster is claimed to evidentially support dark matter, an important component in the ${\rm{\Lambda }}$ CDM cosmology. I argue that such ${\rm{\Lambda }}$ CDM-based models of individual galaxy clusters should be explanatory to meet such claims, but hardly in an ontic sense, due to galaxy cluster anisotropies, empirically equivalent non- ${\rm{\Lambda }}$ CDM-based models, and currently unaccountable cases. I propose that adopting an alternative epistemic/representational conception of scientific explanation can maintain the explanatory nature of individual galaxy cluster models, cope with the three complications, and be potentially generalizable to other branches of astrophysics.