The Dwarfs Beyond: Relating Stellar and Halo Mass in Dwarf Galaxies to z ~ 1

Do the kinematics and mass profiles of dwarf galaxies present a fundamental challenge to standard cold dark matter (CDM) models? New, deep spectroscopy using DEIMOS on Keck for hundreds of low stellar mass (10⁷-10⁹ M_⊙ star-forming galaxies at intermediate redshift (0.2 < z < 1) addresses this inquiry in a way that is less subject to cosmic variance and environmental bias than previous, more local work. Half of this sample reveals resolved, doppler-shifted nebular emission, used to constrain rotation curves. From these we can construct the stellar mass Tully-Fisher relation to masses as low as ~10⁷ M_⊙, and a persistent discrepancy is found between predictions from simulations and models compared to our observations. We suggest on-going and future tests that will be more effective in distinguishing between the effects of baryonic feedback and alternative models of dark matter in this remarkable regime.