Constraints on Quenching of $z\lesssim2$ Massive Galaxies from the Evolution of the average Sizes of Star-Forming and Quenched Populations in COSMOS

Understand

We use $>$9400 $\log(m/M_{\odot})>10$ quiescent and star-forming galaxies at $z\lesssim2$ in COSMOS/UltraVISTA to study the average size evolution of these systems, with focus on the rare, ultra-massive population at $\log(m/M_{\odot})>11.4$.

• The large 2-square degree survey area delivers a sample of $\sim400$ such ultra-massive systems.
• Accurate sizes are derived using a calibration based on high-resolution images from the Hubble Space Telescope.
• We find that, at these very high masses, the size evolution of star-forming and quiescent galaxies is almost indistinguishable in terms of normalization and power-law slope.