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Astronomy

The Relation Between Surface Brightness and Central Black Hole Mass

Quick fact

Dense, bright elliptical galaxies tend to host more massive central black holes; galaxies with lower central surface brightness harbor lighter black holes. This correlation holds even though the black hole is millions of times smaller than the galaxy.

Why this is interesting

You might think a galaxy's brightness tells you only about its stars—but astronomers have found that it also reveals the mass of the monstrous black hole hiding at its center. How could a city of stars be linked to a single dark object?