UV and U-band luminosity functions from CLAUDS and HSC-SSP - I. Using four million galaxies to simultaneously constrain the very faint and bright regimes to z ∼ 3

TLDR: In this article, the authors constrain the rest-frame FUV, NUV and U-band luminosity functions with unprecedented precision from z ∼ 0.2 to z ∼ 3.

Abstract: We constrain the rest-frame FUV (1546 A), NUV (2345 A), and U-band (3690 A) luminosity functions (LFs) and luminosity densities (LDs) with unprecedented precision from z ∼ 0.2 to z ∼ 3 (FUV, NUV) and z ∼ 2 (U band). Our sample of over 4.3 million galaxies, selected from the CFHT Large Area U-band Deep Survey (CLAUDS) and HyperSuprime-Cam Subaru Strategic Program (HSC-SSP) data lets us probe the very faint regime (down to MFUV, MNUV, MU ≃ −15 at low redshift), while simultaneously detecting very rare galaxies at the bright end down to comoving densities 1 it is due to the evolution of both $M^\star _{\rm UV}$ and the characteristic number density $\phi ^\star _{\rm UV}$. In contrast, the U-band LF has an excess of faint galaxies and is fitted with a double-Schechter form; $M^\star _{U}$, both $\phi ^\star _{U}$ components, and the bright-end slope evolve throughout 0.2 < z < 2, while the faint-end slope is constant over at least the measurable 0.05 < z < 0.6. We present tables of our Schechter parameters and LD measurements that can be used for testing theoretical galaxy evolution models and forecasting future observations.