2004ApJ...600L..15C

We present evidence for the dramatically different morphology between the rest-frame UV and 7 µm mid-IR emission of VV 114 and Arp 299, two nearby (z∼0) violently interacting luminous infrared galaxies (LIRGs). Nearly all LIRGs are interacting systems, and it is currently accepted that they dominate the IR emission at z>1. LIRGs located at z=1-2 could easily be detected as unresolved sources in deep optical/near-IR ground-based surveys as well as in upcoming 24 µm surveys with the Space Infrared Telescope Facility. We demonstrate that the spatial resolution of these surveys will result in blending of the emission from unresolved interacting components. An increased scatter will thus be introduced in the observed optical-to-mid-IR colors of these galaxies, leading to a systematic underestimation of their dust content.