Ejective feedback as a quenching mechanism in the 1.5 billion years of the universe: detection of neutral gas outflow in a $z=4$ recently quenched galaxy

Understand

The confirmation of massive quiescent galaxies emerging within the first billion years of the universe poses intriguing questions about the mechanisms of galaxy formation.

• There must be highly efficient processes at work to shut down star formation in galaxies at cosmic dawn.
• I present the detection of neutral outflowing gas in a massive recently quenched galaxy at $z=4$, showing ejective back as a quenching mechanism.
• Based on JWST spectrum, the star formation rate of this has been declining with a rapid e-folding timescale of $\sim50$ Myrs.