Acknowledgements:

The Illustris project acknowledges support from many sources.

VS acknowledges support by the DFG Research Centre SFB-881 "The Milky Way System" through project A1, and by the European Research Council under ERC-StG EXAGAL-308037. GS acknowledges support from the HST grants program, number HST-AR- 12856.01-A. Support for program #12856 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. LH acknowledges support from NASA grant NNX12AC67G and NSF grant AST-1312095. DX acknowledges support from the Alexander von Humboldt Foundation. SB was supported by NSF grant AST-0907969. DN acknowledges support from XSEDE grant AST-130032, which is supported by National Science Foundation grant number OCI-1053575.

The Illustris simulation was run on the CURIE supercomputer at CEA/France as part of PRACE project RA0844, and the SuperMUC computer at the Leibniz Computing Centre, Germany, as part of project pr85je. Further simulations were run on the Harvard Odyssey and CfA/ITC clusters, the Ranger and Stampede supercomputers at the Texas Advanced Computing Center through XSEDE, and the Kraken supercomputer at Oak Ridge National Laboratory through XSEDE.