O. Ivy Wong, K. Schawinski, S. Kaviraj, K. L. Masters, R. C. Nichol, C. Lintott, W. C. Keel, D. Darg, S. P. Bamford, D. Andreescu, P. Murray, M. J. Raddick, A. Szalay, D. Thomas, J. VandenBerg
We present a study of local post-starburst galaxies (PSGs) using the
photometric and spectroscopic observations from the Sloan Digital Sky Survey
(SDSS) and the results from the Galaxy Zoo project. We find that the majority
of our local PSG population have neither early- nor late- type morphologies but
occupy a well-defined space within the colour-stellar mass diagram, most
notably, the low-mass end of the "green valley" below the transition mass
thought to be the mass division between low-mass star-forming galaxies and
high-mass passively-evolving bulge-dominated galaxies. Our analysis suggests
that it is likely that a local PSG will quickly transform into "red", low-mass
early-type galaxies as the stellar morphologies of the "green" PSGs largely
resemble that of the early-type galaxies within the same mass range. We propose
that the current population of PSGs represents a population of galaxies which
is rapidly transitioning between the star-forming and the passively-evolving
phases. Subsequently, these PSGs will contribute towards the build-up of the
low-mass end of the "red sequence" once the current population of young stars
fade and stars are no longer being formed. These results are consistent with
the idea of "downsizing" where the build-up of smaller galaxies occurs at later
epochs.
View original:
http://arxiv.org/abs/1111.1785
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