The elli
ptic flow,
v2, of muons from heavy-flavour hadron decays at forward rapidity (
2.5<y<4) is measured in Pb–Pb collisions at
pt>
pt> with the ALICE detector at the LHC. The scalar prod
uct, two- and four-particle
Q cumulants and Lee–Yang zeros methods are used. The dependence of the
v2 of muons from heavy-flavour hadron decays on the collision centrality, in the range 0–40%, and on transverse momentum,
pT, is studied in the interval
3<pT<10 GeV/c. A positive
v2 is observed with the scalar prod
uct and two-particle
Q cumulants in semi-central collisions (10–20% and 20–40% centrality classes) for the
pT interval from 3 to about
5 GeV/c with a significance larger than 3
σ , based on the combination of statistical and systematic uncertainties. The
v2 magnitude tends to decrease towards more central collisions and with increasing
pT. It becomes compatible with zero in the interval
6<pT<10 GeV/c. The results are compared to models describing the interaction of heavy quarks and open heavy-flavour hadrons with the high-density medium formed in high-energy heavy-ion collisions.