PerspectiveAstrophysics

Galaxy-Scale Mergers and Globular Clusters

Science  25 Feb 2000:
Vol. 287, Issue 5457, pp. 1410-1411
DOI: 10.1126/science.287.5457.1410

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Summary

The formation of globular clusters and the origin of galaxy shapes, longstanding mysteries in astrophysics that were long viewed as disjoint, have recently turned out to be closely connected, as Schweizer discusses in this Perspective. Hubble Space Telescope observations of colliding and merging galaxies have shown that globular clusters--densely packed aggregates of 10to 10stars--apparently form from massive gas clouds in galaxies that get seriously perturbed. Giant elliptical galaxies contain a particularly high number of globular clusters, which fall into a metal-poor and a metal-rich groups, implying two major episodes of globular cluster formation. The metal-rich group is interpreted as evidence for the formation of elliptical galaxies through major galaxy mergers.