A primer on the histories of early type galaxies

Presented by Dr. Guy Worthey, Department of Physics and Astronomy, St. Ambrose University

I explore in a broad-brush way the spectrum of possible origins for the (almost certainly heterogeneous) collection of objects classified as elliptical galaxies. I consider a single monolithic gas cloud collapse shortly after the big bang, ongoing large-galaxy merging events, smaller ongoing accretion events, and even continuous star formation as from cooling flow gas. Direct and indirect age estimators are employed along with chemistry indicators to try to sort out which possibilities are viable.