By means of the Lie algebra expansion method, the centrally extended conformal algebra in two dimensions and the $\mathfrak{ bms}_{ 3}$ algebra are obtained from the Virasoro algebra. We extend this result to construct new families of expanded Virasoro algebras that turn out to be infinite dimensional lifts of the so-called $\mathfrak{ B}_{ k}$, $\mathfrak{ C}_{ k}$ and $\mathfrak{ D}_{ k}$ algebras recently introduced in the literature in the context of (super)gravity. We also show how some of these new infinite-dimensional symmetries can be obtained from expanded Ka\v{ c}-Moody algebras using modified Sugawara constructions. Applications in the context of three-dimensional gravity are briefly discussed.
Categories: hep-th