Mapping Spatial Variations of HI Turbulent Properties in the Small and Large Magellanic Cloud

TL;DR

This study introduces new methods for mapping the spatial variations of HI turbulence properties in the Magellanic Clouds, revealing uniform turbulence in the SMC and diverse, feedback-influenced turbulence in the LMC.

Contribution

The paper develops novel techniques for spatially mapping HI turbulence properties and applies them to the Magellanic Clouds, uncovering differences in turbulence driven by stellar feedback and large-scale dynamics.

Findings

SMC shows uniform HI turbulence with no local feedback effects.

LMC exhibits diverse turbulence, with steepened SPS slopes near HII regions.

Localized steepening in LMC outskirts suggests disk flaring or ram-pressure effects.

Abstract

We developed methods for mapping spatial variations of the spatial power spectrum (SPS) and structure function (SF) slopes, with a goal of connecting neutral hydrogen (HI) statistical properties with the turbulent drivers. The new methods were applied on the HI observations of the Small and Large Magellanic Clouds (SMC and LMC). In the case of the SMC, we find highly uniform turbulent properties of HI, with no evidence for local enhancements of turbulence due to stellar feedback. Such properties could be caused by a significant turbulent driving on large-scales. Alternatively, a significant line-of-sight depth of the SMC could be masking out localized regions with a steeper SPS slope caused by stellar feedback. In contrast to the SMC, the LMC HI shows a large diversity in terms of its turbulent properties. Across most of the LMC, the small-scale SPS slope is steeper than the large-scale slope due to the presence of the HI disk. On small spatial scales, we find several areas of localized steepening of the SPS slope around major HII regions, with the 30 Doradus region being the most prominent. This is in agreement with predictions from numerical simulations which suggest steepening of the SPS slope due to stellar feedback eroding and destroying interstellar clouds. We also find localized steepening of the large-scale SPS slope in the outskirts of the LMC. This is likely caused by the flaring of the HI disk, or alternatively ram-pressure stripping of the LMC disk due to the interactions with the surrounding halo gas.