The Stellar Masses of ~40,000 UV Selected Galaxies from the WiggleZ Survey at 0.3<z<1.0: Analogues of Lyman Break Galaxies?

TL;DR

This study characterizes stellar masses and star formation rates of ~40,000 UV-selected galaxies at 0.3<z<1.0 from the WiggleZ survey, revealing their similarities to high-redshift Lyman break galaxies and emphasizing the importance of NIR data for accurate mass estimates.

Contribution

It provides the first large-scale analysis of UV luminous galaxies at intermediate redshifts, highlighting the impact of NIR photometry and stellar population assumptions on mass estimates.

Findings

Median stellar masses range from 10^9.6 to 10^10.4 M_sun depending on detection.

Including NIR data improves the precision of stellar mass estimates.

Star formation rates are 3-10 M_sun/yr, comparable to high-redshift Lyman break galaxies.

Abstract

We characterise the stellar masses and star formation rates in a sample of almost 40000 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 UKIDSS LAS and the mid infrared WISE All-Sky Survey. We find that ~30% of the UV luminous WiggleZ galaxies are detected at >5sigma in the UKIDSS-LAS at all redshifts. An even more luminous subset of 15% are also detected in the WISE 3.4 and 4.6um bands. 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 SED fitting. The median stellar masses are log10(M*/M0)=9.6\pm0.7, 10.2\pm0.5 and 10.4\pm0.4 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. 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 0.3dex in the stellar masses. We find that the best-fit M/LK is significantly lower (by ~0.4 dex) than that predicted by simple optical colour based estimators, in particular for the bluer galaxies with younger best-fit ages. The WiggleZ galaxies have star formation rates of 3-10 M0/yr 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~2-3.(abridged)