Which came first: supermassive black holes or galaxies? Insights from JWST

Insights from JWST observations suggest that AGN feedback evolved from ashort-lived, high redshift phase in which radiatively cooled turbulence and/ormomentum-conserving outflows stimulated vigorous early star formation(``positive'' feedback), to late, energy-conserving outflows that depleted halogas reservoirs and quenched star formation. The transition between these tworegimes occurred at $z\sim 6$, independently of galaxy mass, for simpleassumptions about the outflows and star formation process. Observationalpredictions provide circumstantial evidence for the prevalence of massive blackholes at the highest redshifts hitherto observed, and we discuss their origins.