Down-sizing Forever

TL;DR

This paper discusses cosmic down-sizing, showing that larger galaxies formed their stars earlier than smaller ones, challenging traditional hierarchical models of galaxy formation.

Contribution

It provides evidence that contradicts the hierarchical clustering paradigm, suggesting a need to revise theories of galaxy and cosmic structure evolution.

Findings

Larger galaxies' major star-forming epochs occurred earlier.

Evidence supports cosmic down-sizing over hierarchical models.

Galaxies may not form through traditional processes.

Abstract

Evidence for cosmic down-sizing has been growing over the last decade. It is now clear that the major star-forming epoch for the largest galaxies occurred earlier than for smaller galaxies. This not only runs counter to the popular hierarchical clustering picture, but points to an even more radical revision of our ideas of the evolution of cosmological structure. Galaxies do not form at all.