Introducing the Photometric Maximum Likelihood Method: Galaxy Luminosity Functions at z<1.2 in MUSYC-ECDFS

TL;DR

This paper introduces a novel maximum likelihood method for deriving galaxy luminosity functions directly from multi-band photometric data without relying on spectroscopic redshifts, applied to a large galaxy survey.

Contribution

The paper presents a new photometric maximum likelihood technique that bypasses photometric redshift estimation, improving the accuracy of luminosity function measurements.

Findings

Deep luminosity functions reach M_r=-14

Field galaxy LF deviates from Schechter form

Steep upturn at intermediate magnitudes due to late-type galaxies

Abstract

We present a new maximum likelihood method for the calculation of galaxy luminosity functions from multi-band photometric surveys without spectroscopic data. The method evaluates the likelihood of a trial luminosity function by directly comparing the predicted distribution of fluxes in a multi-dimensional photometric space to the observations, and thus does not require the intermediate step of calculating photometric redshifts. We apply this algorithm to ~27,000 galaxies with m_R<=25 in the MUSYC-ECDFS field, with a focus on recovering the luminosity function of field galaxies at z<1.2. Our deepest LFs reach M_r=-14 and show that the field galaxy LF deviates from a Schechter function, exhibiting a steep upturn at intermediate magnitudes that is due to galaxies of late spectral types.