Galaxy Luminosity Function of the Coma Cluster from Deep u ′ − g ′ − r ′ Wendelstein Imaging Data

Abstract We derive the g ′ -band galaxy luminosity function (GLF) of quenched resolved galaxies in the Coma cluster from a deep-imaging survey with ≈1.5 deg 2 around the cluster center. The data set comprises deep u ′ -, g ′ -, and r ′ -band data obtained with the Wendelstein Wide Field Imager on the 2.1 m Fraunhofer Wendelstein Telescope reaching median 3 σ surface brightness limits in 10″ × 10″ boxes of ( 30.0 u ′ , 29.6 g ′ , 28.7 r ′ ) mag arcsec − 2 . We measure structural parameters across a large dynamic range in galaxy brightness ( − 24.5 g ′ mag ⪅ M ⪅ − 11.3 g ′ mag ), from the brightest cluster galaxy to low-luminosity dwarfs, including compact dwarf galaxies and ultradiffuse galaxies. We automatically identify more than 6000 cluster member candidates based on their membership on the quiescent sequence in the u ′ − g ′ versus g ′ − r ′ color–color diagram. The structural parameters of bright galaxies are obtained via isophotal modeling, and fully automated parametric image fitting for faint ones. Injection-recovery tests and two identically analyzed reference fields provide statistical corrections for completeness and contamination, yielding a representative GLF that reliably probes the faint end and may serve as a benchmark for future studies. We report a best-fit single Schechter g