The accretion histories of brightest cluster galaxies from their stellar population gradients

Paola Oliva-Altamirano*, Sarah Brough, Jimmy, Kim Vy Tran, Warrick J. Couch, Richard M. McDermid, Chris Lidman, Anja von der Linden, Rob Sharp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

We analyse the spatially resolved stellar populations of nine local (z < 0.1) Brightest Cluster Galaxies (BCGs) observed with VIMOS in Integral Field Unit mode. Our sample is composed of seven slow-rotating and two fast-rotating BCGs. We do not find a connection between stellar kinematics and stellar populations in this small sample. The BCGs have shallow metallicity gradients (median Δ[Fe/H]=-0.11 ± 0.1), high central metallicities (median [Fe/H][α/Fe] = 0 = 0.13 ± 0.07), and a wide range of central ages (from 5 to 15 Gyr). We propose that the reason for this is diverse evolutionary paths in BCGs. 67 per cent of the sample (6/9) show ~7 Gyr old central ages, which reflects an active accretion history, and 33 per cent of the sample (3/9) have central ages older than 11 Gyr, which suggest no star formation since z = 2. The BCGs show similar central stellar populations and stellar population gradients to early-type galaxies of similar mass (Mdyn > 1011.3M⊙) from the ATLAS3D survey (median [Z/H] = 0.04 ± 0.07, Δ[Z/H] = -0.19 ± 0.1). However, massive early-type galaxies from ATLAS3D have consistently old ages (median Age = 12.0 ± 3.8 Gyr). We also analyse the close massive companion galaxies of two of the BCGs. These galaxies have similar stellar populations to their respective BCGs.

Original languageEnglish
Pages (from-to)3347-3359
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume449
Issue number4
DOIs
Publication statusPublished - 1 Jun 2015

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