Emerging AdS from Extremally Rotating NS5-branes

We investigate the near-horizon limit of extremally rotating NS5-branes. The resulting geometry has SL(2,R)×U(1)2 isometry. The asymptotic symmetry group contains a chiral Virasoro algebra, and we obtain two different realizations depending on the boundary conditions we impose. When one of the two angular momenta vanishes, the symmetry is enhanced to AdS3. The entropy of the boundary theory can be estimated from the Cardy formula and it agrees with the Bekenstein-Hawking entropy of the bulk theory. We can embed the extremally rotating NS5-brane geometry in an exactly solvable string background, which may yield microscopic understanding of this duality, especially about the mysterious enhancement of the symmetry from AdS2 to AdS3. The construction suggests emerging Virasoro symmetries in the extreme corner of the (1+5) dimensional little string theory.