Galaxy Clustering with Pan-STARRS1 and GAMA

Abstract

The first theme of this thesis is preparing for the exploitation of a new photometric galaxy survey, Pan STARRS1 (PS1). The second is measuring projected galaxy clustering in the Galaxy and Mass Assembly (GAMA) survey, and using these measurements to constrain models of galaxy formation.
The PS1 survey is obtaining imaging in 5 bands (gP1, rP1, iP1, zP1 and yP1) for the 3π steradian survey, the largest optical survey ever conducted. The finished survey will have spatially varying depth, due to the survey strategy. We present a method to correct galaxy number counts and clustering for this based on a simplified signal-to-noise ratio. A star/galaxy separation method calibrated using synthetic images is also presented. By using our techniques on a 69 deg.2 region of science verification data, we show PS1 measurements of the two point angular correlation
appear reliable down to rP1 < 22.5. This work lays the foundations for exploiting 3π data for large scale structure.
The GAMA survey is a multi-wavelength, spectroscopic survey of galaxies, covering 180 deg.2 . We measure the projected correlation function and its redshift evolution as a function of luminosity, mass and colour. We find redder, more massive and more luminous galaxies are more clustered in three redshift slices over the range 0.0 < z < 0.5. We find that these trends are reproduced in the galaxy formation model of Bower et al. (2006). We also find redder galaxies have steeper correlation functions; a trend which is also reproduced by the model. However, we find that red galaxies in the model are too clustered, particularly on small scales. Our measurements are new constraints on theories of galaxy formation.