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Special Colloquium |
Dr. Callum Lynn
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Australian National University
Observations of neutral hydrogen (HI) within galaxies are an important
tracer to probe the evolution of complex physical processes that occur
within the interstellar medium (ISM). With its close proximity, the gas
of the Milky Way provides us the ideal laboratory to investigate these
processes and the eventual formation of molecular clouds at scales
beyond the sub-grid resolution of most numerical ISM simulations.
Observations of this calibre are vital to test our current theoretical
understanding of the turbulent cascade and formation of cold gas. The
SKA precursor, ASKAP, has observed the Milky Way foreground towards the
Magellanic System in unprecedented detail, with its current spatial
resolution and unbiased detection manner cataloguing hundreds of Milky
Way HI absorption sources within a relatively small field of view,
rivalling the combined catalogue of previous detections across the
entire sky. I will present recent work done by the GASKAP-HI
Collaboration using these latest advancements in source density made by
the GASKAP-HI survey. More specifically I will discuss the unique
prospect of calculating the structure function of optical depth and
other HI properties across a filamentary region, to better understand
the spatial structure of the cold neutral medium and its formation. I
will also discuss the correlation between HI and dust and how the
increased background source density has enabled the ability to detect
higher temperature phases of gas through stacking spectra to improve the
signal-to-noise beyond the current observational sensitivity of ASKAP.