${\text{AdS}}_2\times S^7$ solutions from D0 $-$ F1 $-$ D8 intersections

Abstract

We study an exhaustive analytic class of massive type IIA backgrounds preserving sixteen real supercharges and enjoying $\text{SL}(2,\mathbb{R})\times \text{SO}(8)$ bosonic symmetry. The corresponding geometry is described by ${\text{AdS}}_2\times S^7$ warped over a line, which turns out to emerge from taking the near-horizon limit of D0 $-$ F1 $-$ D8 intersections. By studying the singularity structure of these solutions we find the possible presence of localized O8/D8 sources, as well as of fundamental strings smeared over the $S^7$. Finally we discuss the relation between the aforementioned solutions and the known ${\text{AdS}}_7\times S^2$ class through double analytic continuation.

12 pages; v2: minor changes, references added