Galaxy And Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies

L.J.M. Davies, Aaron Stuart Graham Robotham, Simon Peter Driver, Mehmet Alpaslan, I.K. Baldry, J. Bland-Hawthorn, S. Brough, M.J.I. Brown, M.E. Cluver, M.J. Drinkwater, C. Foster, M.W. Grootes, I.S. Konstantopoulos, M.A. Lara-López, Á.R. López-Sánchez, J. Loveday, M.J. Meyer, A.J. Moffett, P. Norberg, M.S. OwersC.C. Popescu, R. De Propris, R. Sharp, R.J. Tuffs, L. Wang, S.M. Wilkins, L. Dunne, N. Bourne, M.W.L. Smith

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The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes likely to arise on short time-scales and be directly related to the galaxy-galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different time-scales for pair galaxies, targeting numerous star- formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries are consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-duration SFR indicators (e.g. Ha), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs.
Original languageEnglish
Pages (from-to)616-636
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date8 Jul 2015
Publication statusPublished - 1 Sept 2015


  • Galaxies: evolution
  • Galaxies: interactions
  • Galaxies: star formation


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  • GAMA Panchromatic Data Release

    Driver, S. P. (Creator), Wright, A. H. (Creator), Andrews, S. K. (Creator), Davies, L. J. (Creator), Kafle, P. R. (Creator), Lange, R. (Creator), Moffett, A. J. (Creator), Mannering, E. (Creator), Robotham, A. S. G. (Creator), Vinsen, K. (Creator), Andrae, E. (Creator), Baldry, I. K. (Creator), Bauer, A. E. (Creator), Bamford, S. P. (Creator), Bland-Hawthorn, J. (Creator), Bourne, N. (Creator), Brough, S. (Creator), Brown, M. J. I. (Creator), Cluver, M. E. (Creator), Croom, S. (Creator), Colless, M. (Creator), Conselice, C. J. (Creator), da Cunha (Elisabete da Cunha, E. (Creator), De Propris, R. (Creator), Drinkwater, M. (Creator), Dunne, L. (Creator), Eales, S. (Creator), Edge, A. (Creator), Frenk, C. (Creator), Graham, A. W. (Creator), Grootes, M. (Creator), Holwerda, B. W. (Creator), Hopkins, A. M. (Creator), Ibar, E. (Creator), van Kampen, E. (Creator), Kelvin, L. S. (Creator), Jarrett, T. (Creator), Jones, D. H. (Creator), Lara-Lopez, M. A. (Creator), Liske, J. (Creator), Lopez-Sanchez, A. R. (Creator), Loveday, J. (Creator), Maddox, S. J. (Creator), Madore, B. (Creator), Mahajan (Smriti Mahajan), S. (Creator), Meyer, M. (Creator), Norberg, P. (Creator), Penny, S. J. (Creator), Phillipps, S. (Creator), Popescu, C. (Creator), Tuffs, R. J. (Creator), Peacock, J. A. (Creator), Pimbblet, K. A. (Creator), Prescott, M. (Creator), Rowlands, K. E. (Creator), Sansom, A. E. (Creator), Seibert, M. (Creator), Smith, M. (Creator), Alpaslan, M. (Creator), Sutherland, W. J. (Creator), Taylor, E. N. (Creator), Valiante, E. (Creator), Vazquez-Mata, J. A. (Creator), Wang, L. (Creator), Wilkins, S. M. (Creator) & Williams, R. (Creator), International Centre for Radio Astronomy Research , 1 Feb 2016


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