2000/07/26 by John Kormendy, Kormendy, John
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0007400
4 pages, 1 color figure, TeX, Science (Perspective), in press
arxiv created 2000/07/26 · openalex publication_date 2000/07/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Surveys with the Hubble Space Telescope find supermassive black holes (BHs) of 10**6 to 10**9.5 solar masses in every galaxy that has an elliptical-galaxy-like "bulge" component. BHs appear to be standard equipment in galaxy bulges. At the 2000 June meeting of the American Astronomical Society, two groups announced the discovery of a tight correlation between BH mass and the global velocity dispersion of stars in the host galaxy bulge (astro-ph/0006053 and astro-ph/0006289). Also, BH mass scales with bulge mass; the median BH mass fraction is 0.15 % of the bulge mass. In contrast, BH mass does not scale with disk properties. Pure disk galaxies - ones that lack a bulge component - must have BH mass fractions that are much smaller than the BH mass fractions in bulges. These results imply a close connection between BH growth and bulge (but not disk) formation. Observations increasingly support the hypothesis that the major events that form a bulge or elliptical galaxy and the main growth phases of its BH - when it shone like a quasar - were the same events. These and other results are leading to a profound change in how astronomers view BHs. More than just exotica needed to explain rare active galactic nuclei, they are becoming an integral part of our understanding of galaxy formation.