| Abstract
| - We present a new near-infrared imaging survey in the four CFHTLS deep fields: the WIRCam Deep Survey or “WIRDS”. WIRDS comprises extremely deep, high quality ( FWHM ~ 0.6″) J, H, and Ks imaging covering a total effective area of 2.1 deg 2 and reaching AB 50% completeness limits of ≈ 24.5. We combine our images with the CFHTLS to create a unique eight-band ugrizJHKS photometric catalogues in the four CFHTLS deep fields; these four separate fields allow us to make a robust estimate of the effect of cosmic variance for all our measurements. We use these catalogues in combination with ≈ 9800 spectroscopic redshifts to estimate precise photometric redshifts ( σΔ z/(1 + z) ≲ 0.03 at i < 25), galaxy types, star-formation rates and stellar masses for a unique sample of ≈ 1.8 million galaxies. Our JHKs number counts are consistent with previous studies. We apply the “ BzK” selection to our gzK filter set and find that the star forming BzK selection successfully selects 76% of star-forming galaxies in the redshift range 1.4 < z < 2.5 in our photometric catalogue, based on our photometric redshift measurement. Similarly the passive BzK selection returns 52% of the passive 1.4 < z < 2.5 population identified in the photometric catalogue. We present the mass functions of the total galaxy population as a function of redshift up to z = 2 and present fits using double Schechter functions. A mass-dependent evolution of the mass function is seen with the numbers of galaxies with masses of M ≲ 10 10.75 still evolving at z ≲ 1, but galaxies of higher mass reaching their present day numbers by z ~ 0.8−1. This is consistent with the present picture of downsizing in galaxy evolution. We compare our results with the predictions of the GALFORM semi-analytical galaxy formation model and find that the simulations provide a relatively successful fit to the observed mass functions at intermediate masses (i.e. 10 ≲ log ( M/ M⊙) ≲ 11). However, as is common with semi-analytical predictions of the mass function, the GALFORM results under-predict the mass function at low masses (i.e. log ( M/ M⊙) ≲ 10), whilst the fit as a whole degrades beyondredshifts of z ~ 1.2. All photometric catalogues and images are made publicly available from TERAPIX and CADC.
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