%0 Generic %1 snyder2015galaxy %A Snyder, Gregory F. %A Torrey, Paul %A Lotz, Jennifer M. %A Genel, Shy %A McBride, Cameron K. %A Vogelsberger, Mark %A Pillepich, Annalisa %A Nelson, Dylan %A Sales, Laura V. %A Sijacki, Debora %A Hernquist, Lars %A Springel, Volker %D 2015 %K galaxy morphology simulation %T Galaxy Morphology and Star Formation in the Illustris Simulation at z=0 %U http://arxiv.org/abs/1502.07747 %X We study how optical galaxy morphology depends on mass and star formation rate (SFR) in the Illustris Simulation. To do so, we measure automated diagnostics of galaxy structure in 10808 simulated galaxies at z=0 with stellar masses 10^9.7 < M_*/M_sun < 10^12.3. We add observational realism to idealized synthetic images and measure non-parametric statistics in rest-frame u, g, i, and H band images from four directions. We find that the Illustris simulation creates a morphologically diverse population of galaxies, occupying roughly the observed bulge strength locus, and reproducing median morphology trends versus stellar mass, SFR, and compactness. Optical morphology correlates realistically with rotational structure, following qualitative classification schemes put forth by kinematic surveys. Relative 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 numerical methods. This raises a question of how to construct the best experiments on large galaxy surveys to better distinguish between models. We predict that at fixed halo mass near 10^12 M_sun, galaxies with relatively more disc-like morphologies have higher stellar mass than those with bulge-like morphologies, a possible consequence of the Illustris feedback model acting on massive galaxies. While Illustris galaxies at M_* ~ 10^11 M_sun have a reasonable size distribution, those at M_* ~ 10^10 M_sun have half-light radii larger than observed by roughly a factor of 2. Furthermore, at M_* ~ 10^10.5 through 10^11 M_sun, a relevant fraction of Illustris galaxies have distinct "ring-like" features, such that the bright pixels have an unusually wide spatial extent (M_20 > -1).

@misc{snyder2015galaxy, 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 diagnostics of galaxy structure in 10808 simulated galaxies at z=0 with stellar masses 10^9.7 < M_*/M_sun < 10^12.3. We add observational realism to idealized synthetic images and measure non-parametric statistics in rest-frame u, g, i, and H band images from four directions. We find that the Illustris simulation creates a morphologically diverse population of galaxies, occupying roughly the observed bulge strength locus, and reproducing median morphology trends versus stellar mass, SFR, and compactness. Optical morphology correlates realistically with rotational structure, following qualitative classification schemes put forth by kinematic surveys. Relative 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 numerical methods. This raises a question of how to construct the best experiments on large galaxy surveys to better distinguish between models. We predict that at fixed halo mass near 10^12 M_sun, galaxies with relatively more disc-like morphologies have higher stellar mass than those with bulge-like morphologies, a possible consequence of the Illustris feedback model acting on massive galaxies. While Illustris galaxies at M_* ~ 10^11 M_sun have a reasonable size distribution, those at M_* ~ 10^10 M_sun have half-light radii larger than observed by roughly a factor of 2. Furthermore, at M_* ~ 10^10.5 through 10^11 M_sun, a relevant fraction of Illustris galaxies have distinct "ring-like" features, such that the bright pixels have an unusually wide spatial extent (M_20 > -1).}, added-at = {2015-03-02T09:58:28.000+0100}, author = {Snyder, Gregory F. and Torrey, Paul and Lotz, Jennifer M. and Genel, Shy and McBride, Cameron K. and Vogelsberger, Mark and Pillepich, Annalisa and Nelson, Dylan and Sales, Laura V. and Sijacki, Debora and Hernquist, Lars and Springel, Volker}, biburl = {https://www.bibsonomy.org/bibtex/25de91cd62b3056330f36a2930514a9d6/miki}, description = {[1502.07747] Galaxy Morphology and Star Formation in the Illustris Simulation at z=0}, interhash = {df2bbd9cc98038367c4ebcc6ade62fae}, intrahash = {5de91cd62b3056330f36a2930514a9d6}, keywords = {galaxy morphology simulation}, note = {cite arxiv:1502.07747Comment: 23 pages, 13 figures, submitted to MNRAS}, timestamp = {2015-03-02T09:58:28.000+0100}, title = {Galaxy Morphology and Star Formation in the Illustris Simulation at z=0}, url = {http://arxiv.org/abs/1502.07747}, year = 2015 }