A1 Cosmological Black Holes

Topic

The central figure in this model is the supermassive black hole occupying a galaxy's center.

Supermassive black holes reside at the hearts of virtually all massive galaxies in the universe; quasars are, in fact, supermassive black holes that are actively accreting matter at extreme rates, thereby achieving some of the highest luminosities ever observed.

The close correlation between a supermassive black hole's mass and the velocity dispersion of stars in the surrounding galactic bulge suggests they grew in tandem—a process forming a feedback loop that ties back to the galaxy itself: feedback from the active nucleus—such as winds and jets—regulates star formation within the host galaxy, meaning the black hole's growth ultimately governs the growth of the very galaxy that enabled it to expand.

However, the most distant quasars ever detected imply the existence of supermassive black holes with masses a billion times that of the Sun, already fully formed when the universe was less than seven hundred million years old; this growth rate poses a genuine challenge to standard models of how these objects form.

Direct imaging of the shadow cast by these black holes' event horizons onto their surroundings has confirmed—in two instances—the extreme geometry predicted by general relativity. Thus, from the supermassive black hole that opens this discussion to the confirmed extreme geometry that concludes it—taking in quasars, the feedback loop with the host galaxy, and the challenges posed by the most distant quasars—cosmological black holes demonstrate how a single supermassive black hole ends up both shaping, and being shaped by, the entire galaxy that houses it.

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