Browsing by Author "Elson, E"

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    Measurements of the angular momentum–mass relations in the Simba simulation
    (New Astronomy, 2023) Elson, E; Davé, R; Glowacki, M
    We present measurements of the specific angular momentum content (𝑗) of galaxies drawn from the Simba cosmological hydrodynamic simulations. These relations are broadly consistent with a variety of empirical measurements. We confirm the observational result that the scatter in the stellar 𝑗–𝑀 relation is driven largely by H I content, and measure the dependence of its scatter on the deviations of galaxies from other important scaling relations. For a given stellar mass, H i-rich/poor galaxies have more/less-than-average stellar specific angular momentum.
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    The redshift evolution of the baryonic Tully-Fisher relation in SIMBA
    (Oxford university press, 2021) Glowacki, M; Elson, E; Dav´e, R
    The baryonic Tully–Fisher relation (BTFR) is an important tool for constraining galaxy evolution models. As 21-cm HI emission studies have been largely restricted to low redshifts, the redshift evolution of the BTFR is less studied. The upcoming LADUMA survey (Looking At the Distant Universe with the MeerKAT Array) will address this. As preparation for LADUMA, we use the SIMBA hydrodynamical galaxy formation simulation from the SIMBA-hires (25 h −1Mpc)3 run to generate rotational velocity measures from galaxy rotation curves (Vflat) and HI spectral line profile widths (W50 and W20) at three different redshifts (z = 0, 0.5, and 1). Using these measures, together with the dark matter velocity dispersion and halo mass, we consider the redshift evolution of the BTFR of SIMBA galaxies. We find that LADUMA will be successful in detecting weak redshift evolution of the BTFR, provided that auxiliary data are used to distinguish galaxies with discy morphologies. W20 spectral line widths give lower scatter and more pronounced redshift evolution compared to W50. We also compare these rotational velocity measures to the dark matter velocity dispersion across redshift and galaxy morphology. We find weak redshift evolution between rotational velocity and the dark matter halo mass, and provide fits for estimating a galaxy’s dark matter halo mass from HI spectral line widths. This study with SIMBA showcases the importance of upcoming, deep Square Kilometre Array pathfinder surveys such as LADUMA, and provides predictions to compare with the redshift evolution of the BTFR and galaxy dark matter content from HI rotational velocity measures.