In this paper we present a measurement of the elliptic ($v_2$), triangular ($v_3$) and quadrangular ($v_4$) anisotropic azimuthal flow over a wide range of pseudorapidity ($\eta$). The measurement is performed on Pb--Pb collisions at $\sqrt{s_{\text{NN}}} = 2.76$ TeV using the ALICE detector at the Large Hadron Collider (LHC). The flow harmonics are found using two- and four-particle correlations. The analysis is performed in nine different centrality ranges covering central to peripheral collisions. It is found that the shape of $v_n(\eta)$ is largely independent on centrality for the three flow harmonics. The ratio of different flow harmonics at large $|\eta|$ can be used to further constrain the shear viscosity to entropy density ratio. We asses the validity of extended longitudinal scaling of $v_2$ by comparing to lower energy measurements. Finally, the measurements are compared with a theoretical model.

Approval talk: https://indico.cern.ch/event/330318/session/0/contribution/1/material/sl...

JIRA: https://alice.its.cern.ch/jira/browse/PWGCF-55