In this thesis we investigate the evolution of galaxies since z = 3. There are several methods to measure the star formation rate (SFR) of galaxies, they all however have drawbacks. Several studies have investigated the SFR at high redshifts using SFR tracers that suffer from uncertainties, either from the tracer used, or from the uncertainties correcting for the effects of dust. We have new measurements of the Ha emission line for a sample of galaxies at =~1; Ha is a more accurate SFR-tracer than other commonly used tracers, but until now had been technically difficult to measure at : > 0.85. We investigate methods to correct these observations for dust and we use these measurements to investigate the relation between SFR, stellar mass and colour. We find that there is a drop in the fraction of massive (M, > 1011 M.) star-forming galaxies at = < 0.9 and that the fraction of all galaxies that are star-forming drops steadily and significantly with redder (U — B) colours. We find that the M„-SFR (galaxy main sequence, GMS) is flatter than previously measured and that for the most massive galaxies, star formation shuts off abruptly at =~1.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:718862 |
| Date | January 2016 |
| Creators | Twite, Joanathan W. |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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