  The measurements of flow harmonics $v_2$-$v_6$ using the event plane and two
particle correlations methods in broad $p_T$, $\eta$ and centrality ranges
using the ATLAS detector at LHC are presented. ATLAS recorded about 9 $\mu
\textrm{b}^{-1}$ of lead-lead collision data in the 2010 heavy ion run. The
full azimuthal acceptance of the ATLAS detector in $\pm2.5$ units of
pseudorapidity for charged hadrons and the large amount of data allows for a
detailed study of the flow harmonics. The $p_T$, centrality and $\eta$ ranges
where the two methods give consistent $v_n$ and where they disagree are
discussed. It is shown that the ridge as well as the so called "mach-cone" seen
in two particle correlations are largely accounted for by the collective flow.
Some scaling relations in the $p_T$ dependence of the $v_n$ are also discussed.
