Figure 2

$v_{2}[2]$ with $|\Delta\eta|>$ 0 (circles), $|\Delta\eta| >$ 0.4 (diamonds) and $|\Delta\eta| >$ 0.8 (squares) for various centrality classes in Pb--Pb collisions at $\sqrt{s_{_{\rm NN}}} = 2.76$~TeV. Hydrodynamic calculations with MC-Glauber initial conditions~ and $\eta/s =$ 0.08, with MC-KLN initial conditions and $\eta/s =$ 0.20~, with Trento initial conditions and temperature dependent $\eta/s$~ and AMPT initial conditions and $\eta/s =$ 0.08~ are shown in green dot-dashed and orange dashed curves, and magenta and grey shaded areas, respectively.
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