Which came first: supermassive black holes or galaxies?

Insights from JWST observations are shedding new light on the chronology and nature of AGN in the context of early galaxy evolution. I argue that AGN feedback evolved from a short-lived, high redshift phase when relatively dense momentum-conserving central outflows in dusty ultracompact galaxy hosts stimulated vigorous early star formation (“positive” feedback) in the dense circumnuclear medium, transiting at around z~6 to energy-conserving outflows that depleted gas reservoirs and quenched star formation (“negative” feedback). Observational implications of this coevolution scenario are supported by circumstantial evidence for the prevalence of massive black holes at the highest redshifts, preceding the bulk of star formation. I discuss massive black hole origins, via alternative hypotheses ranging from accelerated growth via mergers in nuclear star clusters to growth via bursts of super-Eddington accretion as well as a possible primordial origin.

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