Using data from the DEEP2 Galaxy Redshift Survey and HST /ACS imaging in the Extended Groth Strip , we select nearly 100 interacting galaxy systems including kinematic close pairs and morphologically identified merging galaxies . Spitzer MIPS 24 \mu m fluxes of these systems reflect the current dusty star formation activity , and at a fixed stellar mass ( M _ { * } ) the median infrared luminosity ( L _ { IR } ) among merging galaxies and close pairs of blue galaxies is twice ( 1.9 \pm 0.4 ) that of control pairs drawn from isolated blue galaxies .
Enhancement declines with galaxy separation , being strongest in close pairs and mergers and weaker in wide pairs compared to the control sample .
At \overline { z } \sim 0.9 , 7.1 \% \pm 4.3 \% of massive interacting galaxies ( M _ { * } > 2 \times 10 ^ { 10 } M _ { \odot } ) are found to be ULIRGs , compared to 2.6 \% \pm 0.7 \% in the control sample .
The large spread of L _ { IR } / M _ { * } among interacting galaxies suggests that this enhancement may depend on the merger stage as well as other as yet unidentified factors ( e.g. , galaxy structure , mass ratio , orbital characteristics , presence of AGN or bar ) .
The contribution of interacting systems to the total IR luminosity density is moderate ( \lesssim 36 \% ) .