Theoretical models and tests of cosmology 

State-of-the-art cosmological simulations of structure formation with high mass resolution provide a new tool for probing the clustering properties of low mass dark matter halos. Such simulations can be used to identify an analogous sample of dwarf subhalos to complement our observational program. With full 6D phase space information for a sample of dwarf subhalo pairs we can ask questions like: how well can ΛCDM theory reproduce the observed pair fraction of low mass galaxies at low redshift? What are the typical orbital parameters and mass ratios of dwarf pairs? What kind of environments are pairs of dwarfs typically found? How common are classic examples of dwarf binaries, such as the Magellanic Clouds? How common are triples or larger groups?

We will utilize the dark matter (DM) only version of Illustris to identify our dwarf subhalos and investigate these questions. 

Signatures of Dwarf-Dwarf Interactions in the Stellar Periphery of Magellanic Irregulars 

N-body simulations of the interaction history between the LMC and SMC illustrate that dwarf-dwarf interactions can leave their imprints in the stellar periphery of the primary dwarf, even well after the two have completely merged. Results of this study were published in Besla et al. 2016 and the paper was featured as a AAS Nova article: A History of Collisions Between the Magellanic Clouds.


The simulated interaction history of the LMC and SMC in isolation (i.e., without the Milky Way). The top left panel shows the SMC–LMC separation as a function of time; the remaining panels show the system at different stages of the simulation. Only particles associated with the LMC are shown here; the SMC’s position is indicated by a blue star. (Besla et al. 2016)