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

Ferreras, I, Hopkins, A M, Gunawardhana, M L P, Sansom, A E, Owers, M S, Driver, S, Davies, L, Robotham, A, Taylor, E N, Konstantopoulos, I, Brough, S, Norberg, P, Croom, S, Loveday, J, Wang, L and Bremer, M (2017) Galaxy and Mass Assembly (GAMA): probing the merger histories of massive galaxies via stellar populations. Monthly Notices of the Royal Astronomical Society, 468 (1). pp. 607-619. ISSN 0035-8711

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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.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Depositing User: Billy Wichaidit
Date Deposited: 19 May 2017 08:35
Last Modified: 19 May 2017 09:24
URI: http://sro.sussex.ac.uk/id/eprint/68131

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Project NameSussex Project NumberFunderFunder Ref
Astronomy Centre Rolling GrantG0679STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/F002858/1