Star Formation Shut Down by Multiphase Gas Outflow in a Galaxy at a Redshift of 2.45

Understand

Large-scale outflows driven by supermassive black holes are thought to play a fundamental role in suppressing star formation in massive galaxies.

• However, direct observational evidence for this hypothesis is still lacking, particularly in the young universe where star formation quenching is remarkably rapid, thus requiring effective removal of gas as opposed to slow gas heating.
• While outflows of ionized gas are commonly detected in massive distant galaxies, the amount of ejected mass is too small to be able to suppress star formation.
• Gas ejection is expected to be more efficient in the neutral and molecular phases, but at high redshift these have only been observed in starbursts and quasars.