Morphological quenching of star formation: making early-type galaxies red

Understand

We point out a natural mechanism for quenching of star formation in early-type galaxies.

• It automatically links the color of a galaxy with its morphology and does not require gas consumption, removal or termination of gas supply.
• Given that star formation takes place in gravitationally unstable gas disks, it can be quenched when a disk becomes stable against fragmentation to bound clumps.
• This can result from the growth of a stellar spheroid, for instance by mergers.