Adelaide Seminar: Ultra-compact mini-halos as probes of small-scale cosmology

High-amplitude over-densities in the early Universe are expected to gravitationally collapse shortly after matter-radiation equality, triggering the formation of so-called ultracompact minihalos (UCMHs). Because the masses of the ensuing UCMHs are directly linked to the scales of the overdensities giving rise to them, UCMHs turn out to be the most sensitive probe available of early-time, small-scale cosmology. I will describe our current understanding of UCMH structure and formation, the present and forthcoming limits on their abundance from gamma-rays, pulsar timing and optical microlensing, and the implications for the primordial power spectrum of perturbations, non-Gaussianities, cosmic strings and inflation.

Wed, 20 Jan 2016