UBC Theses and Dissertations

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UBC Theses and Dissertations

Faint galaxy observations and model predictions Hogg, David William


Difficulties with direct comparisons of corrected observational data and model predictions are discussed in the context of faint galaxy number counts and redshift distributions. By simulating images, based on various model universes, and reducing the images via a variety of algorithms, concerns regarding surface brightness biases, systematic and random photometry errors, and incompleteness corrections can be explored. Two software tools have been developed to aid in this investigation, a faint object photometry package (bigphot), and an image simulator. The simulations suggest that attempts to extend number count observations as deep as possible via incompleteness corrections are suspect. Models in which number evolution of the galaxy population has a (1 + z)η redshift dependence on the normalization of the luminosity function (ϕ* in the Schechter function) suggests a value of η between 1 and 3.

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