MIGHTEE-Hi: The relation between the Hi gas in galaxies and the cosmic web
Date
2022Author
Tudorache, Madalina N.
Jarvis, Matthew J.
Heywood, Ian
Metadata
Show full item recordAbstract
We study the 3D axis of rotation (3D spin) of 77 Hi galaxies from the MIGHTEE-Hi Early Science observations, and its
relation to the filaments of the cosmic web. For this Hi-selected sample, the alignment between the spin axis and the closest
filament (|cos 𝜓|) is higher for galaxies closer to the filaments, with h|cos 𝜓|i = 0.66 ± 0.04 for galaxies < 5 Mpc from their
closest filament compared to h|cos 𝜓|i = 0.37±0.08 for galaxies at 5 < 𝑑 < 10 Mpc. We find that galaxies with a low Hi-to-stellar
mass ratio (log10 (𝑀HI/𝑀★) < 0.11) are more aligned with their closest filaments, with h|cos 𝜓|i = 0.58 ± 0.04; whilst galaxies
with (log10 (𝑀HI/𝑀★) > 0.11) tend to be mis-aligned, with h|cos 𝜓|i = 0.44 ± 0.04. We find tentative evidence that the spin axis
of Hi-selected galaxies tend to be aligned with associated filaments (𝑑 < 10 Mpc), but this depends on the gas fractions. Galaxies
that have accumulated more stellar mass compared to their gas mass tend towards stronger alignment.