A deep i-selected multi-waveband galaxy catalogue in the COSMOS field

TL;DR

This paper presents a comprehensive deep multi-waveband galaxy catalogue in the COSMOS field, including photometric redshifts, and analyzes galaxy luminosity evolution up to redshift 3.

Contribution

It provides a new deep, homogeneous multi-band galaxy catalogue with accurate photometric redshifts and publicly available data, improving galaxy evolution studies.

Findings

Photometric redshifts have ~0.035 accuracy with ~2% outliers.

The galaxy luminosity function shows brightening of M* and decreasing phi* with redshift.

The catalogue aligns well with previous surveys like the FORS Deep Field.

Abstract

In this paper we present a deep and homogeneous i-band selected multi-waveband catalogue in the COSMOS field covering an area of about 0.7 square-degree. Our catalogue with a formal 50 percent completeness limit for point sources of i~26.7 comprises about 290.000 galaxies with information in 8 passbands. We combine publicly available u, B, V, r, i, z, and K data with proprietary imaging in H band. We discuss in detail the observations, the data reduction, and the photometric properties of the H-band data. We estimate photometric redshifts for all the galaxies in the catalogue. A comparison with 162 spectroscopic redshifts in the redshift range 0 < z < 3 shows that the achieved accuracy of the photometric redshifts is (Delta_z / (z_spec+1)) ~0.035 with only ~2 percent outliers. We derive absolute UV magnitudes and investigate the evolution of the luminosity function evaluated in the rest-frame UV at 1500 Angstrom. There is a good agreement between the LFs derived here and the LFs derived in the FORS Deep Field. We see a similar brightening of M_star and a decrease of phi_star with redshift. The catalogue including the photometric redshift information is made publicly available.