Paola Oliva-Altamirano edited section_Introduction_label_sec_intro__.tex  almost 9 years ago

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\\\\  Integral Field Unit (IFU) spectroscopy is a valuable tool to explore the spatially-resolved kinematics and stellar populations of galaxies. The SAURON \citep{ZEEUW02} and ATLAS$^{3D}$ \citep{CAPPELLARI11a} surveys have used IFU spectroscopy to explore a significant sample of early-type galaxies in the local Universe. \citet{KUNTSCHNER10} and \citet{ATLAS3D} presented the stellar population analysis of the SAURON and ATLAS$^{3D}$ samples, respectively, finding that 40 per cent of the galaxies typically show contributions from young stellar populations connected to low mass, fast rotator systems. In contrast, they find that slow rotators are generally consistent with old ($\geq 10$ Gyr) stellar populations. The most massive systems (stellar mass $\geq 10^{10.5}$M$_{\odot}$) have the flattest metallicity gradients. However, the ATLAS$^{3D}$ sample contains 21 galaxies with dynamical masses greater than $10^{11.3}$M$_{\odot}$, and only one of those is a BCG (M87).  \\\\  \citet{JIMMY13} analysed the kinematics and photometry of a sample of 10 BCGs observed with the VIMOS IFU, of which 4 have close massive companions. If BCGs were the product of many minor mergers they would be expected to be slow-rotating galaxies. \citet{JIMMY13} found that 30 per cent of the BCGs in their sample are fast rotators. The simulations of \citet{NAAB13}, predict that angular momentum mostly depends on the gas content of the galaxies involved in the interaction, suggesting that the slow or fast rotation could be a temporary state. \citet{JIMMY13}, also find through photometric analysis $G-M_{20}$;\citep[hola][]{LOTZ08} $G-M_{20}$\citep[][]{LOTZ08};that 40 per cent of the galaxies in the sample have undergone a minor merger within the last 0.2 Gyr.   \\\\  Our paper is the third in a series analysing the spatially-resolved spectra of BCGs \citep[after][]{BROUGH11,JIMMY13}. We present here the spatially$-$resolved stellar populations of the BCG sample presented in \citet{JIMMY13}. This is the first IFU analysis dedicated to the stellar populations of BCGs. We will investigate whether BCG accretion histories are different from those of the general massive early-type galaxy population by comparing our measurements to those from SAURON and ALTLAS$^{3D}$.  \\\\  We present the sample selection and observations in Section 2. Section 3 describes the stellar kinematic and photometric measurements from \citet{JIMMY13}. It also describes the early-type galaxy samples of SAURON \citep{KUNTSCHNER10} and ATLAS$^{3D}$ \citep{ATLAS3D} to which we will compare our sample BCGs throughout the paper. Section 4 presents the stellar population analysis. Section 5 summarises the main results. These are later discussed in Section 6. Our conclusions are presented in Section 7. The cosmology adopted throughout this paper is H$_0$=70 kms$^{-1}$ Mpc$^{-1}$, $\Omega_M$=0.3, $\Omega_{\Lambda}$=0.7.