  Particles produced in heavy ion collisions carry information about
anisotropies present already in the early state of the system and play a
crucial role in understanding the Quark Gluon Plasma and its evolution. We
explore the angular power spectrum of particle multiplicities in such heavy ion
collisions to extract fluctuations in particle multiplicities on the surface a
sphere. Results are presented for Pb-Pb data at $\sqrt{s_{NN}} =
2.76\mathrm{TeV}$, extracted from the ALICE open data portal. We find that odd
modes of the power spectrum display a power-law behavior with corresponding
index $\beta$, which is found to be close to unity. We also demonstrate that
the angular power spectrum allows us to extract accurately the flow
coefficients of non-central collisions.
