Trends in [alpha/Fe] as a Function of Morphology and Environment
Cosmic Chemical Evolution
Peter
Watson
Date Submitted
2021-04-30 15:23:00
University of Oxford
P. J. Watson, R. L. Davies, and other members of the SAMI team
We present a new set of measurement of [alpha/Fe] for galaxies in the SAMI galaxy survey. We show that an increase in [alpha/Fe] in high-density environments (HDEs) is not driven by an increase in the red fraction of galaxies. The alpha-enhancement is morphology dependent, being strongest in ellipticals, and occurs primarily at low velocity dispersions (200km/s), we find no difference in the [alpha/Fe] ratio of galaxies, and hence infer that the integrated star-formation timescales cannot differ substantially between high-sigma galaxies across varied environments.
We also present an analysis comparing the residual dependence of [alpha/Fe] against the kinematic properties of the sample, primarily against the spin proxy, lambda_R. We show that for a spectroscopically selected quenched subsample, the intrinsic spin of a galaxy appears to have no relation to the duration of star formation prior to quenching.
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