May 29, 2018 to June 3, 2018
Hyatt Regency Indian Wells Conference Center
US/Pacific timezone

Using Microhalos to Probe the Universe's First Second

May 30, 2018, 2:20 PM
20m
North Foyer | Ironwood Room (Hyatt Regency Indian Wells Conference Center)

North Foyer | Ironwood Room

Hyatt Regency Indian Wells Conference Center

44600 Indian Wells Lane, Indian Wells, CA 92210, USA

Speaker

Prof. Adrienne Erickcek (University of North Carolina at Chapel Hill)

Description

As remnants of the earliest stages of structure formation, the smallest dark matter halos provide a unique probe of the primordial density fluctuations generated during inflation and the evolution of the early Universe. Any enhancement to the small-scale matter power spectrum will trigger the formation of dark matter halos far earlier than otherwise expected. Consequently, observational limits on the abundance of early-forming ultra-compact minihalos (UCMHs) place a powerful upper bound on the amplitude of the small-scale power spectrum, which in turn constrains inflationary models. Numerical simulations of UCMH formation reveal that these constraints need to be revised: UCMHs do not have the steep power-law density profiles predicted by spherical collapse. The abundance of microhalos also encodes information about the evolution of the Universe prior to Big Bang nucleosynthesis because deviations from radiation domination accelerate the growth of small-scale density perturbations. The resulting population of microhalos significantly boosts the dark matter annihilation rate, making it possible to use gamma-ray observations to learn about the evolution of the Universe during its first second.
E-mail [email protected]
Funding source National Science Foundation PHY-1417446

Primary author

Prof. Adrienne Erickcek (University of North Carolina at Chapel Hill)

Presentation materials