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Paper: Star Formation Rates, Metallicities, and Colours as Probes of Merger Timelines
Volume: 477, Galaxy Mergers in an Evolving Universe
Page: 241
Authors: Scudder, J. M.; Patton, D. R.; Ellison, S. L.; Torrey, P.; Mendel, J. T.
Abstract: Pairs of interacting galaxies show significant alterations to their colours, gas-phase metallicities, and SFRs. By investigating the spectroscopic and photometric properties of a sample of interacting galaxies, these changes can be probed. By exploiting the statistical power of the SDSS DR7, we construct a sample of interacting pairs with stringent selection criteria, and develop a methodology that allows us to significantly detect very small deviations for each pair in our sample, relative to a control sample. These deviations can then be interpreted as a function of projected separation. By subdividing the sample based on visual classifications of morphological disturbance, we are able to further investigate these shifts away from control values. We find that galaxies are affected by their encounter out to projected separations of at least 80 kpc h-1. Metallicities shift to significantly lower values over a broader range of projected separations for the morphologically selected sample. Through a comparison with theoretical models, we interpret the form of these trends as the signature of coalescing galaxies at small separations, and of post-pericentric galaxies blurred by projection effects at wider separations.
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