Cold Dark matter (CDM) is believed to be the dominant mass component of the Universe, yet its presence is only inferred indirectly. Its true nature remains elusive. Many independent observational probes support our current standard paradigm and theoretical framework, in which all structure is produced by gravitational aggregation of CDM. Our current thinking revolves around a single putative dark matter candidate, and the options most exhaustively explored are classes of weakly interacting massive particles like the neutralino as candidates. Gaps between observations and predictions have been recently reported that motivate exploration of a wider class of beyond CDM models. More recently, earnest exploration of lighter particle species like axions has received momentum in both theoretical and experimental studies.
As part of this project, we intend to phenomenologically explore a well motivated alternate dark matter model that includes self-interactions (SIDM) in which scale/environment dependent self-interactions are permitted. This is part of a longer term, more exhaustive program and in this exploratory proposal, we intend to investigate a new approach to modeling that combines two flavors of DM - the conventional CDM + a version of self-interacting DM. We will focus on first constructing a model that will involve dual components that combine CDM and provide theoretical predictions and observable astrophysical signatures.
Our goal is to establish a calculational framework that will enable directly connecting particle dark matter models to potentially observable signatures in the high and low redshift Universe - we lay the groundwork and build the first building block in this project. Our unique take here is the focus on strong gravitational lensing signatures and inference therefrom. In this project, we use the recently reported Galaxy-Galaxy Strong Lensing discrepancy in galaxy clusters as the backdrop to explore an alternate dark matter model.
