Topology of HI in the Large Magellanic Cloud

Abstract

We have analyzed the HI aperture synthesis image of the Large Magellanic Cloud (LMC), using an objective and quantitative measure of topology to understand the HI distribution hosting a number of holes and clumps of various sizes in the medium. The HI distribution shows different topology at four different chosen scales. At the smallest scales explored (19-29 pc), the HI mass is distributed in such a way that numerous clumps are embedded on top of a low density background. At the larger scales from 73 to 194 pc, it shows a generic hole topology. These holes might have been formed mainly by stellar winds from hot stars. At the scales from 240 to 340 pc, slightly above the disk scale-height of the gaseous disk, major clumps in the HI map change the distribution to have a slight clump topology. These clumps include the giant cloud associations in the spiral arms and the thick filaments surrounding superholes. At the largest scales studied (390-485 pc), the hole topology is present again. Responsible to the hole topology at this scale are a few superholes which seem mainly associated with supernova explosions in the outer disk. The gaps between the bar and spiral arms have a minor effect on the topology at this scale.

6 pages, 5 figures, accepted for publication in ApJ