AdS$_3$ solutions with exceptional supersymmetry

Understand

Among the possible superalgebras that contain the AdS$_3$ isometries, two interesting possibilities are the exceptional $F(4)$ and $G(3)$.

• Their R-symmetry is respectively SO(7) and $G_2$, and the amount of supersymmetry ${\cal N}=8$ and ${\cal N}=7$.
• We find that there exist two (locally) unique solutions in type IIA supergravity that realize these superalgebras, and we provide their analytic expressions.
• In both cases, the internal space is obtained by a round six-sphere fibred over an interval, with an O8-plane at one end.