Evolution of the Stellar Mass Density of Galaxies Since Redshift 1.0

At variance to other methods of mass estimation of galaxies, stellar masses can be estimated also at higher redshifts and therefore with reduced angular resolutions, when observing with ground based instruments. For a sample of 25000 galaxies drawn from the COMBO-17 survey stellar masses are estimated. For this purpose a method is used that is based on the COMBO-17 multi-color classification. A library suitable for this purpose is developed, and the classification with this library delivers an estimation of the redshift and the spectral energy distribution. The stellar mass-to-light ratio, that is known from the library for all types of spectral energy distribution, together with the flux measurement in one of the COMBO-17 filters in the optical regime delivers an estimation of the stellar mass for the galaxies in the survey. The stellar masses estimated in this way are used for an estimation of the stellar mass function and of the integrated stellar mass density in the redshift regime 0 < z < 1. Resulting from this an increase of the stellar mass density by a factor of 1.6 since redshift 1 is determined. This result is in good agreement to predictions of semianalytic models of galaxy formation and evolution. The comparison to an integration of the star formation rate from the Madau plot over the lookback time shows a good agreement to this relative mass increase but the absolute values are 4-5 times higher than the mass density determined in this work.