Pitt-CMU Colloquium: Andrey Kravtsov (University of Chicago)

Stress-testing LCDM structure formation paradigm on small scales

I will present a galaxy formation model within the Lambda Cold Dark Matter (LCDM) framework that is calibrated on the results of galaxy formation simulations and some of the empirical properties of nearby dwarf galaxies. I will then use the model to interpret a number of ostensible challenges to the LCDM framework, such as the "too-big-to-fail" problem, the Milky Way "plane of satellites" problem, and the "dark-matter-deficient" ultra-diffuse galaxies. I will show that none of these pose a serious challenge to LCDM paradigm within the current observational uncertainties because the corresponding observations can be explained within the standard galaxy formation modeling framework. At the same time, dwarf galaxies provide strong constraints on deviations from the LCDM power spectrum on small scales of up to k~100/Mpc and on the ultra-light wave dark matter models.