C. K. Xu, D. L. Shupe, M. B'ethermin, H. Aussel, S. Berta, J. Bock, C. Bridge, A. Conley, A. Cooray, D. Elbaz, A. Franceschini, E. Le Floc'h, N. Lu, D. Lutz, B. Magnelli, G. Marsden, S. J. Oliver, F. Pozzi, L. Riguccini, B. Schulz, N. Scoville, M. Vaccari, J. D. Vieira, L. Wang, M. Zemcov
The infrared (IR) emission of M_* galaxies (10^{10.4} < M_{star} < 10^{11.0} M_\sun) in galaxy pairs, derived using data obtained in Herschel (PEP/HerMES) and Spitzer (S-COSMOS) surveys, is compared to that of single disk galaxies in well matched control samples to study the cosmic evolution of the star-formation enhancement induced by galaxy-galaxy interaction. Both the mean IR SED and mean IR luminosity of star-forming galaxies (SFGs) in SFG+SFG (S+S) pairs in the redshift bin of 0.6 < z < 1 are consistent with no star-formation enhancement. SFGs in S+S pairs in a lower redshift bin of 0.2 < z < 0.6 show marginal evidence for a weak star-formation enhancement. Together with the significant and strong sSFR enhancement shown by SFGs in a local sample of S+S pairs (obtained using previously published Spitzer observations), our results reveal a trend for the star-formation enhancement in S+S pairs to decrease with increasing redshift. Between z=0 and z=1, this decline of interaction-induced star-formation enhancement occurs in parallel with the dramatic increase (by a factor of ~10) of the sSFR of single SFGs, both can be explained by the higher gas fraction in higher z disks. SFGs in mixed pairs (S+E pairs) do not show any significant star-formation enhancement at any redshift. The difference between SFGs in S+S pairs and in S+E pairs suggests a modulation of the sSFR by the inter-galactic medium IGM in the dark matter halos (DMH) hosting these pairs.
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http://arxiv.org/abs/1210.2362
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