Global Radial Gradient Profiles of Stellar Ages in Plausible Post-Merger Galaxies
American Astronomical Society, AAS Meeting #221, #313.03
Published in Jan 2013
In simulations, we find that merging two gas-rich spiral galaxies usually leads to starbursts and then on to a massive, quiescent spheroidal galaxy. The merger hypothesis for the formation of new elliptical galaxies provides a physical explanation to the observed buildup of this population. A key prediction of which is a brief phase of morphological transformation from highly-disturbed remnant to blue elliptical. We study 14 merger remnant candidates with varying degrees of morphological peculiarities visually selected from a larger parent sample of nearby (0.01 ≤ z ≤ 0.04), massive (M ≥ 10^10 Msun ), concentrated (Petrosian R90/R50 ≥ 2.6), and optically blue galaxies from the SDSS DR4 catalog. Using integral field spectroscopy, we construct two-dimensional spectra of the stellar populations and azimuthally bin them into concentric annuli to determine the age of the stellar populations as a function of radius. Using this data and conclusions from simulations, we seek to distinguish post-mergers from galaxies undergoing other modes of mass assembly.
(c) 2013: American Astronomical Society