Topology of Neutral Hydrogen within the Small Magellanic Cloud

Abstract

ABSTRACT In this paper, genus statistics have been applied to an H i column density map of the Small Magellanic Cloud in order to study its topology. To learn how topology changes with the scale of the system, we provide topology studies for column density maps at varying resolutions. To evaluate the statistical error of the genus, we randomly reassign the phases of the Fourier modes while keeping the amplitudes. We find that at the smallest scales studied ( $40\ \mathrm{pc}\,\leq \lambda \leq 80\ \mathrm{pc}\,$ ), the genus shift is negative in all regions, implying a clump topology. At the larger scales ( $110\ \mathrm{pc}\,\leq \lambda \leq 250\ \mathrm{pc}\,$ ), the topology shift is detected to be negative (a meatball topology) in four cases and positive (a swiss cheese topology) in two cases. In four regions, there is no statistically significant topology shift at large scales.