Year: 2015
Type: article
Abstract: 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 109.7 < M*/Mȯ < 1012.3. 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 1012 Mȯ, disc-dominated galaxies have higher stellar mass than bulge-dominated ones, a possible consequence of the Illustris feedback model. While Illustris galaxies at M* ∼ 1011 Mȯ have a reasonable size distribution, those at M* ∼ 1010 Mȯ have half-light radii larger than observed by a factor of 2. Furthermore, at M* ∼ 1010.5–1011 Mȯ, a relevant fraction of Illustris galaxies have distinct ‘ring-like’ features, such that the bright pixels have an unusually wide spatial extent.
Institutions: Space Telescope Science Institute, California Institute of Technology, Massachusetts Institute of Technology, Smithsonian Institution, Harvard University, Smithsonian Astrophysical Observatory, Center for Astrophysics Harvard & Smithsonian, Columbia University, University of Cambridge, Heidelberg University, Heidelberg Institute for Theoretical Studies
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Yale University, Vanderbilt University, Princeton University, Ohio State University, Harvard University, University of Washington, Johns Hopkins University, Carnegie Mellon University, University of Portsmouth, New Mexico State University, Space Telescope Science Institute, York University, Office of Science, College of Engineering, Michigan State University, Science and Technology Facilities Council, FAS Division of Science, Harvard University, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory
Awards: Towards a Predictive Theory of Galaxy Formation: Cosmological Gas Accretion and Galactic Outflows, WE PROPOSE TO CONSTRUCT A MODEL FOR THE VISIBLE UNIVERSE USING COSMOLOGICAL SIMULATIONS OF STRUCTURE FORMATION. OUR SIMULATIONS WILL INCLUDE BOTH DAR, G433322167, G4518818167, G58316358, G6273510985, Resolving the physics of galaxy formation
OpenAlex ID: W1801137374