The ugrizYJHK luminosity distributions and densities from the combined MGC, SDSS and UKIDSS LAS datasets

TL;DR

This study combines multiple large surveys to produce a comprehensive, homogeneous measurement of galaxy luminosity functions and densities across optical and near-infrared wavelengths within a low redshift volume, revealing a smooth cosmic spectral energy distribution.

Contribution

It provides the first homogeneous optical and near-IR luminosity density measurement, improving data quality and normalisation methods, and reveals a continuous cosmic spectral energy distribution.

Findings

Optical luminosity functions have higher normalisations than previous reports.

Near-IR Schechter parameters differ significantly due to improved imaging data.

The combined dataset shows a smooth cosmic spectral energy distribution.

Abstract

We combine data from the MGC, SDSS and UKIDSS LAS surveys to produce ugrizYJHK luminosity functions and densities from within a common, low redshift volume (z<0.1, ~71,000 h_1^-3 Mpc^3 for L* systems) with 100 per cent spectroscopic completeness. In the optical the fitted Schechter functions are comparable in shape to those previously reported values but with higher normalisations (typically 0, 30, 20, 15, 5 per cent higher phi*-values in u, g, r, i, z respectively over those reported by the SDSS team). We attribute these to differences in the redshift ranges probed, incompleteness, and adopted normalisation methods. In the NIR we find significantly different Schechter function parameters (mainly in the M* values) to those previously reported and attribute this to the improvement in the quality of the imaging data over previous studies. This is the first homogeneous measurement of the extragalactic luminosity density which fully samples both the optical and near-IR regimes. Unlike previous compilations that have noted a discontinuity between the optical and near-IR regimes our homogeneous dataset shows a smooth cosmic spectral energy distribution (CSED). After correcting for dust attenuation we compare our CSED to the expected values based on recent constraints on the cosmic star-formation history and the initial mass function.