University of Minnesota
School of Physics & Astronomy

MN Institute for Astrophysics Colloquium

Friday, October 6th 2017
Speaker: Anna Nierenberg, Ohio State U
Subject: Dwarf galaxy formation and the nature of dark matter
Refreshments to be served in the MIfA Interaction Area (Tate 285-11) following the colloquium.

The abundance of low mass dark matter halos (M_vir <10^9 M_sun) provides key insight into the nature of dark matter, as this abundance depends on the free-streaming length of dark matter at early times and thus its particle properties. Measuring the abundance of low mass halos is difficult as stars become increasingly poor tracers of structure on these scales owing to the complex and not yet well understood physics of star formation in these systems. I will present two complementary approaches to resolving these issues. First I will present measurements of the properties of faint satellite galaxies at a range of redshifts and around a variety of host types and demonstrate how these place strong new constraints on theoretical models of star formation in low mass halos. Secondly, I will present a novel approach to gravitational lensing which makes it possible directly measure the subhalo mass function to masses well below the mass scale of the missing satellite problem in a much larger sample of systems than previously possible. I will conclude by discussing future prospects for these programs given the next generation of ground and space based facilities.

Faculty Host: Liliya L.R. Williams

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