Physical Classification of Galaxies with MOPED/VESPA

TL;DR

This paper demonstrates how high-quality SDSS galaxy spectra can be analyzed using advanced techniques like MOPED/VESPA to reconstruct star formation and metallicity histories, enabling a physical classification of galaxies based on their evolutionary processes.

Contribution

It introduces a method to classify galaxies physically by reconstructing their star formation and metallicity histories from SDSS spectra using MOPED/VESPA.

Findings

Galaxy evolution is primarily determined by current stellar mass.

Galaxy properties relate to the merger rate of dark halos.

Spectral analysis reveals detailed stellar population histories.

Abstract

The availability of high-quality spectra for a large number of galaxies in the SDSS survey allows for a more sophisticated extraction of information about their stellar populations than, e.g., the luminosity weighted age. Indeed, sophisticated and robust techniques to fully analyze galaxy spectra have now reached enough maturity as to trust their results and findings. By reconstructing the star formation and metallicity history of galaxies from the SDSS fossil record and analyzing how it relates to its environment, we have learned how to classify galaxies: to first order the evolution of a galaxy is determined by its present stellar mass, which in turn seems to be governed by the merger rate of dark halos.