The IR Properties of Interacting and Merging Galaxies to z = 1.3

Abstract

We attempt to understand the role of collisions and mergers on the IR-bright galaxy population since a redshift of ~1.5, where the median star formation rate is falling the most rapidly. Using over a thousand 24µm sources from the Extragalactic First Look Survey contained with 50 HST/ACS fields, we classify their morphologies using both the CAS automated method, and a subjective "human inspection" method. We conclude that out to z = 1.5, both the 24µm luminosity and the 24/6.8µm color is not strongly coupled to CAS morphology or merger state. Dusty AGN, on the other hand, seem both more luminous and more symmetrical than star formation-dominated systems.

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