Galaxy and Mass Assembly (GAMA): probing the merger histories of massive galaxies via stellar populations

I. Ferreras*, A. M. Hopkins, M. L.P. Gunawardhana, A. E. Sansom, M. S. Owers, S. Driver, L. Davies, A. Robotham, E. N. Taylor, I. Konstantopoulos, S. Brough, P. Norberg, S. Croom, J. Loveday, L. Wang, M. Bremer

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    10 Citations (Scopus)


    The merging history of galaxies can be traced with studies of dynamically close pairs. These consist of a massive primary galaxy and a less massive secondary (or satellite) galaxy. The study of the stellar populations of secondary (lower mass) galaxies in close pairs provides a way to understand galaxy growth by mergers. Here we focus on systems involving at least one massive galaxy – with stellar mass above 10¹¹M in the highly complete Galaxy and Mass Assembly (GAMA) survey. Our working sample comprises 2692 satellite galaxy spectra (0.1 ≤ z ≤ 0.3). These spectra are combined into high S/N stacks, and binned according to both an ‘internal’ parameter, the stellar mass of the satellite galaxy (i.e. the secondary), and an ‘external’ parameter, selecting either the mass of the primary in the pair, or the mass of the corresponding dark matter halo. We find significant variations in the age of the populations with respect to environment. At fixed mass, satellites around the most massive galaxies are older and possibly more metal-rich, with age differences ∼1–2 Gyr within the subset of lower mass satellites (∼10¹º M). These variations are similar when stacking with respect to the halo mass of the group where the pair is embedded. The population trends in the lower mass satellites are consistent with the old stellar ages found in the outer regions of massive galaxies.

    Original languageEnglish
    Pages (from-to)607-619
    Number of pages13
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number1
    Publication statusPublished - 11 Jun 2017


    • galaxies: evolution
    • galaxies: formation
    • galaxies: interactions
    • galaxies: stellar content


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