The stellar masses of ∼40 000 UV selected Galaxies from the WiggleZ survey at 0.3 < z < 1.0: analogues of Lyman break galaxies?

We characterize the stellar masses and star formation rates in a sample of similar to 40 000 spectroscopically confirmed UV-luminous galaxies at 0.3 < z < 1.0 selected from within the WiggleZ Dark Energy Survey. In particular, we match this UV bright population to wide-field infrared surveys such as the near-infrared (NIR) UKIDSS Large Area Survey (LAS) and the mid-infrared Wide-Field Infrared Survey Explorer (WISE) All-Sky Survey. We find that similar to 30 per cent of the UV-luminous WiggleZ galaxies, corresponding to the brightest and reddest subset, are detected at >5 sigma in the UKIDSS-LAS at all redshifts. An even more luminous subset of 15 per cent are also detected in the WISE 3.4 and 4.6 mu m bands. In addition, 22 of the WiggleZ galaxies are extremely luminous at 12 and 22 mu m and have colours consistent with being star formation dominated. We compute stellar masses for this very large sample of extremely blue galaxies and quantify the sensitivity of the stellar mass estimates to various assumptions made during the spectral energy distribution (SED) fitting. The median stellar masses are log(10)(M-*/M-circle dot) = 9.6 +/- 0.7, 10.2 +/- 0.5 and 10.4 +/- 0.4 for the IR undetected, UKIDSS detected and UKIDSS+WISE detected galaxies, respectively. We demonstrate that the inclusion of NIR photometry can lead to tighter constraints on the stellar masses by bringing down the upper bound on the stellar mass estimate. The mass estimates are found to be most sensitive to the inclusion of secondary bursts of star formation as well as changes in the stellar population synthesis models, both of which can lead to median discrepancies of the order of 0.3 dex in the stellar masses. We conclude that even for these extremely blue galaxies, different SED fitting codes therefore produce extremely robust stellar mass estimates. We find, however, that the best-fitting M/L-K is significantly lower than that predicted by simple optical colour-based estimators for many of the WiggleZ galaxies. The simple colour-based estimator overpredicts M/L-K by similar to 0.4 dex on average. The effect is more pronounced for bluer galaxies with younger best-fitting ages. The WiggleZ galaxies have star formation rates of 3-10 M-circle dot yr(-1) and mostly lie at the upper end of the main sequence of star-forming galaxies at these redshifts. Their rest-frame UV luminosities and stellar masses are comparable to both local compact UV-luminous galaxies as well as Lyman break galaxies at z similar to 2-3. The stellar masses from this paper will be made publicly available with the next WiggleZ data release.