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Bahe, YM, Crain, RA, Kauffmann, G, Bower, RG, Schaye, J, Furlong, M, Lagos, C, Schaller, M, Trayford, JW, Dalla Vecchia, C and Theuns, T (2016) The distribution of atomic hydrogen in EAGLE galaxies: morphologies, profiles, and HI holes. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 456 (1). pp. 1115-1136. ISSN 0035-8711
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Abstract
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.
| Item Type: | Article |
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| Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
| Uncontrolled Keywords: | 0201 Astronomical And Space Sciences |
| Subjects: | Q Science > QB Astronomy |
| Divisions: | Astrophysics Research Institute |
| Publisher: | OXFORD UNIV PRESS |
| Related URLs: | |
| Date Deposited: | 12 Feb 2016 14:06 |
| Last Modified: | 03 Aug 2022 07:47 |
| DOI or ID number: | 10.1093/mnras/stv2674 |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/2930 |
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