Home                 UofT Astronomy and Astrophysics Theses List

The Formation and Evolution of Galaxies: A Deep Submillimeter Survey

Tracy Webb

Doctor of Philosophy 2002
Graduate Department of Astronomy and Astrophysics, University of Toronto

Galaxies are the basic units of the universe and yet we know relatively little about the processes involved in their formation and evolution. Until recently, most advancements in this area of research were due to optical and ultraviolet observations of the high-redshift universe. However, the existence of a far-infrared background of substantial magnitude has highlighted the importance of studying the universe at these longer wavelengths. The commissioning of the Submillimeter Common-User Bolometric Array (SCUBA) on the James Clerk Maxwell Telescope has made this possible and has revolutionized the field of submillimeter cosmology.

This thesis addresses the formation and evolution of galaxies through a large-scale survey for the bright objects responsible for the submillimeter background. A substantial catalogue of 50 sources, selected at 850 micron is presented. Extensive follow-up observations (new and archival) have been assembled, including radio maps from the Very Large Array, optical data from the Canada-France-Redshift Survey, near-infrared imaging from the Canada-France-Hawaii Telescope, Hubble Space Telescope data, and mid-infrared data from the Infrared Space Observatory.

The 850 micron source counts are determined and the contribution of these objects to the far-infrared background is measured allowing us to draw conclusions regarding their cosmic importance. In addition, the strength of the angular clustering of the SCUBA population is investigated.

Determining the counterparts of these objects at other wavelengths is difficult as the SCUBA position is uncertain. Using positional coincidence arguments identifications at radio, mid and near-infrared and optical wavelengths are made. From these data redshifts are estimated and general conclusions about the redshift distribution and the nature of the SCUBA population are drawn.

The relationship between the submillimeter-bright and optically-selected Lyman-break galaxy (LBG) population explored. The average submillimeter flux of the LBGs is measured and possible submillimeter-bright LBGs are discussed. The strength of the cross-clustering between these two populations is also measured.

Reproduced with permission by Marlene Cummins library@astro.utoronto.ca
October 7 2002