Bluck, Asa F LBottrell, ConnorTeimoorinia, HossenHenriques, Bruno M BMendel, JonEllison, Sara LThanjavur, KarunSimard, LucPatton, David RConselice, ChristopherMoreno, Jorge2022-05-022022-05-020035-8711http://hdl.handle.net/1885/264225We investigate the dependence of galaxy structure on a variety of galactic and environmental parameters for ∼500 000 galaxies at z< 0.2, taken from the Sloan Digital Sky Survey data release 7 (SDSS-DR7). We utilize bulge-to-total stellar mass ratio (B/T)* as the primary indicator of galactic structure, which circumvents issues of morphological dependence on waveband. We rank galaxy and environmental parameters in terms of how predictive they are of galaxy structure, using an artificial neural network approach. We find that distance from the star-forming main sequence (ΔSFR), followed by stellar mass (M*), are the most closely connected parameters to (B/T)*, and are significantly more predictive of galaxy structure than global star formation rate (SFR), or any environmental metric considered (for both central and satellite galaxies). Additionally, we make a detailed comparison to the Illustris hydrodynamical simulation and the LGalaxies semi-analytic model. In both simulations, we find a significant lack of bulge-dominated galaxies at a fixed stellar mass, compared to the SDSS. This result highlights a potentially serious problem in contemporary models of galaxy evolution.Support for JM is provided by the National Science Foundation (Division of Astronomical Sciences Award Number 1516374), and by the Harvard Institute for Theory and Computation, through their Visiting Scholars Program. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS website is http: //www.sdss.org/.application/pdfen-AU© 2019 The authorsGalaxydisc – galaxiesbulges – galaxiesevolution – galaxiesformation – galaxiesstar formationgalaxies: structure201910.1093/mnras/stz3632020-12-27