Cosmic evolution of star formation enhancement in close major-merger galaxy pairs since z = 1

C. K. Xu, D. L. Shupe, M. Béthermin, 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. SchulzN. Scoville, M. Vaccari, J. D. Vieira, L. Wang, M. Zemcov

Research output: Contribution to journalArticlepeer-review


The infrared (IR) emission of "M * galaxies" (1010.4 ≤ M star ≤ 1011.0 M) 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 spectral energy distribution 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 of which 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 intergalactic medium (IGM) in the dark matter halos hosting these pairs.

Original languageEnglish (US)
Article number72
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 20 2012
Externally publishedYes


  • galaxies: evolution
  • galaxies: general
  • galaxies: interactions
  • galaxies: starburst

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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