Publication details for Prof Richard BowerBahé, Y. M., Crain, R. A., Kauffmann, G., Bower, R. G., Schaye, J., Furlong, M., Lagos, C., Schaller, M., Trayford, J. W., Dalla Vecchia, C. & Theuns, T. (2016). The distribution of atomic hydrogen in EAGLE galaxies: morphologies, profiles, and H I holes. Monthly Notices of the Royal Astronomical Society 456(1): 1115-1136.
- Publication type: Journal Article
- ISSN/ISBN: 0035-8711, 1365-2966
- DOI: 10.1093/mnras/stv2674
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
We compare the mass and internal distribution of atomic hydrogen (H I) in 2200 present-day central galaxies with Mstar > 1010 M⊙ from the 100 Mpc EAGLE ‘Reference’ simulation to observational data. Atomic hydrogen fractions are corrected for self-shielding using a fitting formula from radiative transfer simulations and for the presence of molecular hydrogen using an empirical or a theoretical prescription from the literature. The resulting neutral hydrogen fractions, , agree with observations to better than 0.1 dex for galaxies with Mstar between 1010 and 1011 M⊙. Our fiducial, empirical H2 model based on gas pressure results in galactic H I mass fractions, [Math Processing Error], that agree with observations from the GASS survey to better than 0.3 dex, but the alternative theoretical H2 formula from high-resolution simulations leads to a negative offset in [Math Processing Error] of up to 0.5 dex. Visual inspection of mock H I images reveals that most H I discs in simulated H I-rich galaxies are vertically disturbed, plausibly due to recent accretion events. Many galaxies (up to 80 per cent) contain spuriously large H I holes, which are likely formed as a consequence of the feedback implementation in EAGLE. The H I mass–size relation of all simulated galaxies is close to (but 16 per cent steeper than) observed, and when only galaxies without large holes in the H I disc are considered, the agreement becomes excellent (better than 0.1 dex). The presence of large H I holes also makes the radial H I surface density profiles somewhat too low in the centre, at [Math Processing Error] (by a factor of ≲ 2 compared to data from the Bluedisk survey). In the outer region ([Math Processing Error]), the simulated profiles agree quantitatively with observations. Scaled by H I size, the simulated profiles of H I-rich ([Math Processing Error]) and control galaxies ([Math Processing Error]) follow each other closely, as observed.