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, Aaron S G Robotham, Edward N. Taylor, I. Konstantopoulos, S. Brough, P. Norberg, S. Croom, J. Loveday, L. Wang, M. Bremer

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)
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Abstract

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 (∼1010 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
Volume468
Issue number1
Early online date28 Feb 2017
DOIs
Publication statusPublished - 1 Jun 2017

Keywords

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

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