The infrared emission of ultraviolet-selected galaxies from z = 0 to z = 1

Abstract

Aims. We want to study the IR (>8 μm) emission of galaxies selected on the basis of their rest-frame UV light in a very homogeneous way (wavelength and luminosity) from z = 0 to z = 1. We compare their UV and IR rest-frame emission to study the evolution in dust attenuation with z as well as to check if a UV selection is capable of tracking all star formation. This UV selection will also be compared to a sample of Lyman break galaxies selected at z 1. Methods.We select galaxies in UV (1500-1800 Å) rest-frame at z = 0, z = 0.6-0.8, z = 0.8-1.2, and with as Lyman break galaxies at z = 0.9-1.3, the samples are compiled to sample the same range of luminosity at any redshift. The UV rest-frame data come from GALEX for z < 1 and the U-band of the EIS survey (at z = 1). The UV data are combined with the IRAS 60 μm observations at z = 0 and the Spitzer data at 24 μm for z > 0 sources. The evolution in the IR and UV luminosities with z is analysed for individual galaxies as well as in terms of luminosity functions. Results.The LIR/LUV ratio is used to measure dust attenuation. This ratio does not seem to evolve significantly with z for the bulk of our sample galaxies, but some trends are found for both galaxies with a strong dust attenuation and UV luminous sources: galaxies with LIR/LUV > 10 are more frequent at z > 0 than at z = 0, and the largest values of LIR/LUV are found for UV faint objects; in contrast, the most luminous galaxies of our samples (LUV > 2 × 1010 L), detected at z = 1, exhibit a lower dust attenuation than fainter ones. The value of LIR/LUV increases with the K rest-frame luminosity of the galaxies at all redshifts considered and shows a residual anticorrelation with LUV. The most massive and UV luminous galaxies exhibit quite high specific star formation rates. Lyman break galaxies exhibit systematically lower dust attenuation than UV-selected galaxies of same luminosity, but similar specific star formation rates. The analysis of the UV + IR luminosity functions leads to the conclusion that up to z = 1, most of the star formation activity of UV-selected galaxies is emitted in IR. Although we are able to infer information about all the star formation from our UV selection at z = 0.7, at z = 1 we miss a large fraction of galaxies more luminous than ≃1011 L. The effect is found to be larger for Lyman break galaxies. © 2009 ESO.