Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Astrophysics and Astronomy
How Do Galaxies Form Their Stars Over Cosmic Time?, Jed H. Mckinney
How Do Galaxies Form Their Stars Over Cosmic Time?, Jed H. Mckinney
Doctoral Dissertations
Galaxies in the past were forming more stars than those today, but the driving force behind this increase in activity remains uncertain. In this thesis I explore the origin of high star-formation rates today and in the past by studying the properties of gas and dust in the cold interstellar medium (ISM) of dusty galaxies over cosmic time. Critically, we do not yet understand how these galaxies could form so many stars. This work began with my discovery of unusual infrared (IR) emission line ratios in the class of dusty galaxies where most of the Universe’s stars were formed. To …
The Clustering Of Young Stellar Clusters In Nearby Galaxies, Kathryn Grasha
The Clustering Of Young Stellar Clusters In Nearby Galaxies, Kathryn Grasha
Doctoral Dissertations
Star clusters form the basic building blocks of galaxies. They span a wide range of ages, from a few million years to billions of years, making them exceptional tracers of the star formation histories of their host galaxies. Star formation is the process by which galaxies build up their stellar populations and their visible mass and occurs in a continuous, hierarchical "social" fashion across a large dynamical range, from individual stars up to kiloparsec-scale ensembles of stellar aggregates. It is the formation, evolution, and eventual destruction of these large hierarchical star-forming complexes that provide an essential role in understanding the …
The Effect Of A Growing Black Hole On The Infrared Emission Of Dusty Galaxies In The Distant Universe, Allison Kirkpatrick
The Effect Of A Growing Black Hole On The Infrared Emission Of Dusty Galaxies In The Distant Universe, Allison Kirkpatrick
Doctoral Dissertations
The buildup of stellar and black hole mass peaked during z=1-3. Infrared (IR) luminous galaxies, which are massive and heavily dust obscured (LIR > 1011 Lsun), dominate the stellar growth during this era, and many are harboring a hidden active galactic nucleus (AGN). We have quantified the contribution of AGN heating to the infrared emission of a large sample of dusty, luminous galaxies from z=0.5-4 using Spitzer mid-IR spectroscopy, available for every source. We classify sources as star forming galaxies, AGN, or composites based on the presence of mid-IR continuum emission due to a dusty …