%0 Generic %1 diemer2019atomic %A Diemer, Benedikt %A Stevens, Adam R. H. %A Lagos, Claudia del P. %A Calette, A. R. %A Tacchella, Sandro %A Hernquist, Lars %A Marinacci, Federico %A Nelson, Dylan %A Pillepich, Annalisa %A Rodriguez-Gomez, Vicente %A Villaescusa-Navarro, Francisco %A Vogelsberger, Mark %D 2019 %K Illustris gas simulation %T Atomic and molecular gas in IllustrisTNG galaxies at low redshift %U http://arxiv.org/abs/1902.10714 %X We have recently developed a framework to estimate the abundance of atomic and molecular hydrogen (HI and H2, respectively) in galaxies in large-volume cosmological simulations. Here we compare the resulting HI and H2 content of IllustrisTNG galaxies to observations. We mostly restrict this comparison to $z 0$ and consider six observational metrics: the overall abundance of HI and H2, their mass functions, gas fractions as a function of stellar mass, the correlation between H2 and star formation rate, the spatial distribution of gas, and the correlation between gas content and morphology. We find generally good agreement between simulations and observations, particularly for the gas fractions and the HI mass-size relation. The H2 mass correlates with star formation rate as expected, revealing an almost constant depletion time that evolves up to z = 2 as observed. However, we also discover a number of tensions with varying degrees of significance, including an overestimate of the total neutral gas abundance at z = 0 by about a factor of two and a possible excess of satellites with no or very little neutral gas. These conclusions are robust to the modelling of the HI/H2 transition. In terms of their neutral gas properties, the IllustrisTNG simulations represent an enormous improvement over the original Illustris run. All data used in this paper are publicly available as part of the IllustrisTNG data release.

@misc{diemer2019atomic, abstract = {We have recently developed a framework to estimate the abundance of atomic and molecular hydrogen (HI and H2, respectively) in galaxies in large-volume cosmological simulations. Here we compare the resulting HI and H2 content of IllustrisTNG galaxies to observations. We mostly restrict this comparison to $z \approx 0$ and consider six observational metrics: the overall abundance of HI and H2, their mass functions, gas fractions as a function of stellar mass, the correlation between H2 and star formation rate, the spatial distribution of gas, and the correlation between gas content and morphology. We find generally good agreement between simulations and observations, particularly for the gas fractions and the HI mass-size relation. The H2 mass correlates with star formation rate as expected, revealing an almost constant depletion time that evolves up to z = 2 as observed. However, we also discover a number of tensions with varying degrees of significance, including an overestimate of the total neutral gas abundance at z = 0 by about a factor of two and a possible excess of satellites with no or very little neutral gas. These conclusions are robust to the modelling of the HI/H2 transition. In terms of their neutral gas properties, the IllustrisTNG simulations represent an enormous improvement over the original Illustris run. All data used in this paper are publicly available as part of the IllustrisTNG data release.}, added-at = {2019-03-01T15:42:03.000+0100}, author = {Diemer, Benedikt and Stevens, Adam R. H. and Lagos, Claudia del P. and Calette, A. R. and Tacchella, Sandro and Hernquist, Lars and Marinacci, Federico and Nelson, Dylan and Pillepich, Annalisa and Rodriguez-Gomez, Vicente and Villaescusa-Navarro, Francisco and Vogelsberger, Mark}, biburl = {https://www.bibsonomy.org/bibtex/255b3ce1995b2f0f5210e55aacc5e6a77/heh15}, description = {Atomic and molecular gas in IllustrisTNG galaxies at low redshift}, interhash = {f41f12c4fa2d66d4758ad17dcb7fcab2}, intrahash = {55b3ce1995b2f0f5210e55aacc5e6a77}, keywords = {Illustris gas simulation}, note = {cite arxiv:1902.10714Comment: 22 pages, 11 figures. Comments welcome. Additional figures and link to data at http://www.benediktdiemer.com/data/hi-h2-in-illustris/}, timestamp = {2019-03-01T15:42:03.000+0100}, title = {Atomic and molecular gas in IllustrisTNG galaxies at low redshift}, url = {http://arxiv.org/abs/1902.10714}, year = 2019 }