Galaxy structure in the low-redshift universe
Galaxy structure, star formation history and environment at intermediate redshifts
Kshitija Kelkar
University of Nottingham
Galaxy interactions are thought to be one of the key mechanisms driving galaxy evolution, affecting the mass assembly, star-formation history,
and structural evolution of galaxies. By z~1 the morphology-density relation is already established, and star formation in high density environments is
also seen to be quenched. To understand the physical drivers behind galaxy transformation, quenching of star formation, and the role that environment plays,
it is therefore important to explore the link between structural disturbance and changes in star formation over a range of environments. We use a sample of 10
clusters and 5 groups from the ESO Distant Cluster Survey (EDisCS) at 0.8 > z > 0.4, with its extensive complementary multiwavelength data, to probe their star
formation properties in the local and global environments. We have used a new method of identifying minor mergers and gravitational interactions of galaxies based
on quantitative analysis of fractional deviation from the smooth symmetric light profile- the Residual Flux Fraction and Asymmetry in the residuals.
Using this quantitative measure of structure as a degree of "roughness", we discover that the galaxy structure can be used as a proxy for the star formation history
of galaxies, with late-type, star forming and merging galaxies being rougher. Moreover, while this roughness correlates with the star formation history of galaxies
even at fixed morphology, the global environment has limited effects on galaxy structure. I will discuss the resulting implications for the role galaxy structure
plays in the morphological transformation and star-formation history of galaxies, and their links with the local and global environments.
16:30 - 18:00
EX - C3 (150)