Invariant mass distribution (top panels a1, b1) and $v_{2}(m_{ll})$ (bottom panels a2, b2) for dimuons in the ranges $2 < p_T< 3$ GeV/$c$ (top left) and for dielectrons in $0 < p_T < 4$ GeV/$c$ (top right), for the 30--50% centrality interval. Fit functions of the invariant mass distributions and $v_{2}(m_{\mu\mu})$, as discussed in Sec. 3, are also shown. 

Bottom panel, invariant mass (c1) and $v_{3}(m_{\mu\mu})$ (c2) distributions for dimuons in the $p_T$ range $2 < p_T < 5$ GeV/$c$ for the 0--50% centrality interval. The $v_{n}(m_{\mu\mu})$ and $v_{2}(m_{ee})$ distributions are plotted with the background flow obtained from the event-mixing procedure and the fit function, as discussed in the text. Only statistical uncertainties are shown.