Topology of Neutral Hydrogen Within the Small Magellanic Cloud

In this paper, genus statistics have been applied to an HI column density map of the Small Magellanic Cloud in order to study its topology. At the smallest scales studied (26 pc ≤ λ ≤ 75 pc) the genus shift is negative, implying a clump topology. At medium scales (75 pc ≤ λ ≤ 125 pc) the topology shifts to a neutral/slightly positive value, indicating a tendency towards a swiss-cheese/hole topology. At large scales (λ ≥ 125 pc) the genus shift varies from region to region but overall tends to return to a slight negative value, consistent with a minor clump topology at the largest scales explored. Other regions with varying areas still show this slight clump topology at low smoothing radii and trend towards a zero shift at higher smoothing radii. Only two of the 62 regions show a significant positive shift, indicating that a hole topology at small scales within the SMC is rare. Subject headings: galaxies: individual (Small Magellanic Cloud) — galaxies: ISM — ISM: neutral hydrogen