Ultracompact minihalos as probes of small-scale cosmology

Astronomy Unit Seminars
Pat Scott
Karim Malik
November 20th, 2015 at 14:30
GO Jones Room 610

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.