Russell Jurek (University of Queensland)

WiggleZ: The luminosity function of UV-selected galaxies - Russell Jurek Colloquium

ATNF Marsfield Lecture Theatre

Abstract

The WiggleZ Dark Energy survey is currently being carried out using the AAOmega instrument on the AAT. It is measuring redshifts for 200,000 star-forming galaxies with the highest star-formation rates. In this talk I will present the 0.1 < z < 1.1 optical and ultraviolet luminosity functions of 39,000 star-forming galaxies that WiggleZ has obtained redshifts for. This sample is 40 times larger than those used previously to measure the luminosity functions of star-forming galaxies over this redshift range. Combined with the large volume probed by the WiggleZ survey, this allows the luminosity functions measured from this sample to probe further into the bright end than has been previously possible. It also allows these luminosity functions to be measured with better precision than ever before.

The luminosity functions presented here extend a couple of magnitudes brighter than existing measurements of star-forming galaxy luminosity functions at this redshift. The shapes of these luminosity functions are dependent upon UV-optical colour and redshift. The luminosity functions demonstrate an excess of galaxies at bright magnitudes, compared to the best-fit Schechter functions. The optical luminosity function abruptly deviates from the Schechter function at r ~ -23, and the ultraviolet luminosity function slowly diverges from the Schechter function at NUV ~ -21. The ultraviolet luminosity function shows that the contribution of these extreme star-forming galaxies to the Universe star-formation increases towards lower redshift, and that the contribution is significant for z < 0.8. This is consistent with the cosmic down-sizing scenario.