Galaxy morphology and star formation in the Illustris Simulation at z = 0

By Gregory F. Snyder, P. Torrey, J. Lotz, Shy Genel, Cameron McBride, M. Vogelsberger, A. Pillepich, D. Nelson, L. Sales, D. Sijacki and 2 more. 2015

136 citations recorded by the source corpus.

We study how optical galaxy morphology depends on mass and star formation rate (SFR) in the Illustris Simulation. To do so, we measure automated galaxy structures in 10 808 simulated galaxies at z = 0 with stellar masses 10^(9.7) < M_*/M_⊙ < 10^(12.3). We add observational realism to idealized synthetic images and measure non-parametric statistics in rest-frame optical and near-IR images from four directions. We find that Illustris creates a morphologically diverse galaxy population, occupying the observed bulge strength locus and reproducing median morphology trends versus stellar mass, SFR, and compactness. Morphology correlates realistically with rotation, following classification schemes put forth by kinematic surveys. Type fractions as a function of environment agree roughly with data. These results imply that connections among mass, star formation, and galaxy structure arise naturally from models matching global star formation and halo occupation functions when simulated with accurate methods. This raises a question of how to construct experiments on galaxy surveys to better distinguish between models. We predict that at fixed halo mass near 10^(12) M_⊙, disc-dominated galaxies have higher stellar mass than bulge-dominated ones, a possible consequence of the Illustris feedback model. While Illustris galaxies at M_* ∼ 10^(11) M_⊙ have a reasonable size distribution, those at M_* ∼ 10^(10) M_⊙ have half-light radii larger than observed by a factor of 2. Furthermore, at M_* ∼ 10^(10.5)–10^(11) M_⊙, a relevant fraction of Illustris galaxies have distinct 'ring-like' features, such that the bright pixels have an unusually wide spatial extent.

Subfields: Astronomy and Astrophysics, Ecology, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/9bfe246d62d377338ee9c90a8086d554e59a415a

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Citations in the corpus

The Illustris simulation: the evolving population of black holes across cosmic time (2014, background): “The same conclusion has been reached in a recent paper by Snyder et al. (2015), where it has been also shown that at a fixed halo mass galaxies with above-average black hole masses have below-average stellar masses and earlier-than-average morphological types.”
The size evolution of star-forming and quenched galaxies in the IllustrisTNG simulation (2017, background): “1011 M in the original Illustris simulation (Vogelsberger et al. 2014a,b; Genel et al. 2014) are larger than observed galaxies by roughly a factor of 2 (Snyder et al. 2015; Bottrell et al. 2017; Furlong et al. 2017).”
The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment (2015, background): “Additional analysis of the same suite of simulations are discussed in Moody et al. (2014), Snyder et al. (2015) and Ceverino et al. (2015b).”
The optical morphologies of galaxies in the IllustrisTNG simulation: a comparison to Pan-STARRS observations (2018, methodology): “…and subsequent analysis of synthetic images from hydrodynamic simulations is quickly becoming a powerful tool to connect galaxy formation theory with observations (e.g. Lotz et al. 2008a; Jonsson et al. 2010; Snyder et al. 2015a,b; Bignone et al. 2017; Bottrell et al. 2017a; Trayford et al. 2017).”
Simulating galaxy formation with the IllustrisTNG model (2017, background): “…order to consistently compare simulated to observed astronomical data, the simulated raw data of synthetic galaxies must be transformed into realistic mock observations (Overzier et al. 2013; Torrey et al. 2015; Snyder et al. 2015; ZuHone & Kowalik 2016; Camps et al. 2016; Bottrell et al. 2017a,b).”