MAGAZ3NE: High Stellar Velocity Dispersions for Ultramassive Quiescent Galaxies at z ? 3*

In this work we publish stellar velocity dispersions, sizes, and dynamical masses for 8 ultra-massive galaxies (UMGs; log($M$/M$_\odot>11$, $z\gtrsim3$) from the Massive Ancient Galaxies At $z>3$ NEar-infrared (MAGAZ3NE) Survey, more than doubling number of such with dispersion measurements at epoch. Using deep Keck/MOSFIRE Keck/NIRES spectroscopy these objects in $H$- $K$-bandpasses, obtain large dispersions $\sim400$ km s$^{-1}$ most objects, which are some highest measured, $\sim40$\% larger those measured similar mass $z\sim1.7$. The sizes also smaller by a factor 1.5-3 compared to same $z\sim1.7$ sample. We combine small masses. galaxies, consistent Chabrier initial function (IMF). Considered alongside previous studies massive quiescent across $0.2<z<4.0$, there is evidence an evolution relation between - ratio as redshift. This implies IMF fewer low stars (e.g., IMF) higher redshifts conflict bottom-heavy Salpeter found their likely $z\sim0$ descendants, though alternative explanations different structure or significant rotation not ruled out. Similar data lower redshifts, see increase normalization dispersion, $z\gtrsim3$ trend steeper that $z\sim0.2$ early-type offset dynamical-to-stellar ratios.