Ten Billion Years of Galaxy Evolution
Abstract
Observations in the Hubble Deep Fields have been used to study the evolution of galaxy morphology over time. The majority of galaxies with z < 1 are seen to be disk like, whereas most objects with z > 2 appear to be either chaotic or centrally concentrated ``blobs''. Such blobs might be the ancestral objects of ellipticals or of galaxy bulges. About 1/3 of objects with z > 2 appear to be in the process of merging. The region with 1 < z < 2 marks an important transition in the global history of star formation from a merger dominated regime at z > 2, to one at z < 1 in which most star formation takes place in galactic disks. It is speculated that the break in the Madau plot at z sim 1.5 might be related to the transition from merger-dominated star formation at z > 2 to disk-dominated star formation at at z < 1.
Cite
@article{arxiv.astro-ph/0204315,
title = {Ten Billion Years of Galaxy Evolution},
author = {Sidney van den Bergh},
journal= {arXiv preprint arXiv:astro-ph/0204315},
year = {2009}
}
Comments
19 pages. 1 figure. To be published in the August 2002 issue of PASP