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Abstract:
Neutral atomic Hydrogen (HI) gas is the fundamental reservoir from
which stars in galaxies are eventually formed. As such, studying the
HI gas properties in galaxies give us important insights into how star
formation proceeds. In addition, the HI gas is affected by internal
mechanisms/processes such as angular momentum (AM), star formation/AGN
feedback, disk instabilities, as well as non-axisymmetric potentials
such as bars. On the other hand, the HI gas is also sensitive to
(external) environmental processes such as tidal and ram-pressure
stripping. Disentangling the degree of influence of these processes on
the HI gas is paramount. In this talk I will show the importance of
resolved HI studies in decoding the effects of both internal and
external processes on galaxy evolution. By virtue of the extended
nature of the HI disks in galaxies, one can derive rotation curves out
to many times their optical radii, making high-resolution HI studies
very important for tracing the total AM in galaxies. I will present
the AM – Mass relation for local galaxies which is fundamental for
constraining our cosmological models. In addition, I will talk about
the connection between AM, disk stability and HI gas fraction in
galaxies. Drawing from the results of a new HI survey of ring
galaxies, I will also highlight the effects of bars in redistributing
the HI gas and star formation in galaxies. Finally, I will present
some new data is being delivered by the ASKAP WALLABY HI survey and
the impact this is likely to have on HI and AM studies of galaxies in
the local Universe as we venture into the SKA era.
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