1206.6108 (A. Cibinel et al.)

The Zurich Environmental Study (ZENS) of Galaxies in Groups along the Cosmic Web. II. Galaxy Structural Measurements and the Concentration of Morphologically-Classified Satellites in Diverse Environments    [PDF]

A. Cibinel, C. M. Carollo, S. J. Lilly, F. Miniati, J. D. Silverman, J. H. van Gorkom, E. Cameron, A. Finoguenov, P. Norberg, A. Pipino, C. S. Rudick, T. Lu, Y. Peng

We present structural measurements of galaxies in the z~0.06 groups of the Zurich Environmental Study (ZENS), a program aimed at establishing how galaxy properties depend on four different environmental parameters. Galaxy structure is quantified both non-parametrically and parametrically, through modeling of the two-dimensional surface brightness profiles of the galaxies. Structural parameters are also derived for subgalactic components, i.e., bulges, disks and bars. We calibrate all structural measurements on a common grid, correcting for biases due to PSF and surface brightness effects as a function of galaxy size, magnitude, light concentration and ellipticity. We use the galaxy bulge-to-total ratios (B/T), in combination with the calibrated non-parametric structural estimators, to implement a quantitative morphological classification scheme that maximizes purity in the morphological classes. We focus on how the concentration (C) of satellite galaxies depends on galaxy mass for separate Hubble types, and on halo mass, group-centric distance and large-scale structure density. At galaxy masses M>10^10 Msun, the concentration of disk satellites is found to increase, with increasing stellar mass, separately within each morphological bin, implying that the increase in C with increasing stellar mass for disk satellites is due, at least in part, to an increase in the galaxy central stellar density at constant B/T. The correlation between C and stellar mass becomes progressively steeper for later morphological types. Disk-satellite concentration shows no dependence on either large-scale structure density or projected group-centric distance. In contrast, at constant galaxy stellar mass above 10^10 Msun the mass of the group halo appears to have an impact on the concentration of disk-dominated satellites being 10% more concentrated in M>10^13.4 Msun groups than in lower mass groups. [Abridged]

View original: http://arxiv.org/abs/1206.6108