Structure Function Analysis of Turbulent Properties in the Small and Large Magellanic Clouds
Abstract
Turbulence plays a key role in the evolution of galaxies, but it is still uncertain which interstellar processes drive turbulence, and at what scales they dominate. Numerical simulations (e.g. Grisdale et al. 2017) show that star formation feedback can drive turbulence on small scales, while Krumholz & Burkhart (2016) argue that large scale turbulence is mostly dominated by gravitational instabilities. We use the structure function analysis to search for turbulent drivers in neutral hydrogen (HI) observations of the Small and Large Magellanic Clouds (SMC and LMC). For the SMC we use new HI observations obtained recently with 16 ASKAP antennas, while for the LMC we use HI observations from a combination of the Parkes single dish telescope and ATCA. By incorporating a rolling kernel we have created a new structure function tool that applies a regional analysis to produce an image of the structure function slopes. We find uniform turbulent properties across the SMC, in agreement with previous studies. The structure function slope varies significantly across the LMC suggesting local stellar feedback enhancements, as well as large-scale effects caused by the geometry of the LMC disk. We compare the structure function slope image with the star-formation surface and stellar density distributions to search for turbulent drivers. The same method is applied on individual velocity channels and the integrated intensity image to separately investigate turbulent fluctuations caused by either velocity or density fields.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23325306Y