Advanced morphological galaxy classification: a comparison of observed and simulated galaxies

Abstract

Encoded within the morphological structure of galaxies are clues related to their formation and evolutionary history. Recent advances pertaining to the statistics of galaxy morphology include sophisticated measures of concentration (C), asymmetry (A) and clumpiness (S). In this study, these three parameters (CAS) have been applied to a suite of simulated galaxies and compared with observational results inferred from a sample of nearby galaxies. The simulations span a range of late-type systems, with masses between ∼10[superscript 10] and ∼10[superscript 12] M[subscript circled dot], and employ star formation density thresholds between 0.1 and 100 cm[superscript −3]. We have found that the simulated galaxies possess comparable concentrations to their observed counterparts. However, the results of the CAS analysis revealed that the simulated galaxies are generally more asymmetric, and that the range of clumpiness values extends beyond the range of those observed. Strong correlations were obtained between the three CAS parameters and colour (B−V), consistent with observed galaxies. Furthermore, the simulated galaxies possess strong links between their CAS parameters and Hubble type, mostly in-line with their observed counterparts.