Topology of Neutral Hydrogen Within the Small Magellanic Cloud

TL;DR

This study applies genus statistics to HI maps of the Small Magellanic Cloud to analyze how its topology varies with spatial scale, revealing predominantly clump-like structures at small scales and mixed topologies at larger scales.

Contribution

It introduces a scale-dependent topological analysis of the SMC's HI distribution using genus statistics, including a method to estimate statistical errors.

Findings

Clump topology at small scales (40-80 pc).

Mixed topologies at larger scales (110-250 pc).

Some regions show no significant topology change.

Abstract

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. To learn how topology changes with the scale of the system, we provide the study of topology for column density maps at varying resolution. 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 ($40 {pc}\leq\lambda\leq 80 {pc}$) the genus shift is in all regions negative, implying a clump topology. At the larger scales ($110 {pc}\leq\lambda\leq 250 {pc}$) the topology shift is detected to be negative in 4 cases and positive (``swiss cheese'' topology) in 2 cases. In 4 regions there is no statistically significant topology shift at large scales.