About Simba

Simba is a state-of-the-art suite of galaxy formation simulations for exploring the co-evolution of galaxies, black holes, and intergalactic gas within a cosmological context.

Simba employs novel multi-scale prescriptions for key physical processes governing galaxy evolution:

  • Gizmo with Meshless Finite Mass hydrodynamics
  • Grackle cooling including on-the-fly self-shielding
  • H2-based star formation and 11-element chemistry
  • Two-phase decoupled winds based on FIRE simulations
  • Torque-limited and Bondi black hole accretion
  • AGN jets, radiative winds, and X-ray feedback
  • On-the-fly dust production and destruction

Simba, tuned only to match the galaxy stellar mass function evolution and the M-sigma relation, reproduces a wide range of observations including:

  • Galaxy color and stellar-to-halo mass bimodality
  • Galaxy-black hole co-evolution
  • Galaxy atomic and molecular contents
  • Group and cluster X-ray scaling relations
  • The Lyman alpha forest at low redshifts
  • AGN luminosity functions
  • Dust-to-gas ratios out to high redshifts
  • Low-redshift CGM absorption lines
  • Sub-millimetre galaxy number counts
Many of these successes are unique to Simba, making it among the most advanced simulations to explore galaxy evolution and baryon cycling within cosmologically-evolving ecosystems.


  • Glowacki et al. (2021): Evolution of Tully-Fisher via linewidths
  • Li et al. (2021): Extinction curves in MW-like galaxies
  • Lovell et al. (2020): SMG 850 micron number counts
  • Lower et al. (2020): How well can SED fitting measure stellar mass?
  • Leung et al. (2020): [CII] in Epoch of Reionization galaxies
  • Davé et al. (2020): HI and H2 properties vs. x[COLD]GASS
  • Glowacki et al. (2020): Baryonic Tully-Fisher relation
  • Appleby et al. (2020): sSFR and gas profiles in the green valley
  • Wu et al. (2020): EoR galaxies in the JWST era
  • Rodiguez Montero et al. (2019): Mergers, starbursts, and quenching
  • Li et al. (2019): Dust properties in Simba from z=0-6
  • Davé et al. (2019): Introducing Simba: Basic predictions
  • Thomas et al. (2021): Radio galaxies in Simba
  • Habouzit et al. (2021): BHs in hydro sims
  • Thomas et al. (2019): Galaxy-BH co-evolution
  • Appleby et al. (2021): CGM in Simba vs. COS-Halos/COS-Dwarfs
  • Sorini et al. (2020): Constraining feedback using CGM HI
  • Hassan et al. (2020): Damped Lyman alpha systems in Simba & TD
  • Christiansen et al. (2020): Solving the Photon Underproduction Crisis
  • Cui et al. (2021): The origin of color bimodality (Nature Astro)
  • Villaescusa-Navarro et al. (2021): CAMELS
  • Moews et al. (2021): Inserting galaxies into halos via ML
  • Kraljic et al. (2020): Connectivity and galaxy properties
  • Borrow et al. (2020): Inter-lagrangian transfer
  • Kraljic et al. (2020): Spin alignments of galaxies and filaments
  • Dickey et al. (2021): Isolated quenched galaxies
  • Williams et al. (2021): Molecular gas in z~1.5 galaxies from ALMA
  • Florez et al. (2021): AGN at Cosmic Noon
  • Katsianis et al. (2021): sSFR function and quenching
  • Donevski et al. (2020): Dust-to-gas in dusty ALMA galaxies
  • Mamon et al. (2020): Very young galaxies in SDSS
  • Iyer et al. (2020): Variability of galaxy star formation histories
  • Sherman et al. (2020): Quiescent galaxies at cosmic noon
  • Carnall et al. (2019): SFH of quiescent galaxies at z~1 in VANDELS
  • Cullen et al. (2019): Stellar metallicities at z~3 in VANDELS
  • Simba Data

    Simba snapshots and galaxy catalogs are available for each of 151 output redshifts from z=20 to z=0.

    The hdf5 Caesar catalogs contain many cross-matched galaxy & halo physical properties, photometry in 130+ FSPS bands, and progenitor/descendant links. To work with these catalogs, it's best to install Caesar.

    All files are listed by snapshot number. outputs.txt shows the mapping of [a z snap#]. In Caesar, you can get the nearest snapshot number to a desired redshift via: snapnum,snapz=caesar.progen.z_to_snap(redshift).

    Getting the data:

    • Clicking on the run name below (e.g. s50) will take you to the directory of snapshots for that run.
    • Clicking on the associated description will take you to the directory of galaxy catalogs.

    Flagship Run

    100 Mpc/h box, 2x1024^3 particles.

    s50: Full Simba physics

    High-Res Run

    25 Mpc/h box, 2x512^3 particles.

    s50: Full Simba physics

    Note: Galaxy catalogs are subject to periodic updates. This repository contains the latest public versions.

    The Simba Team

    Meet the Simba team! We are a loosely-connected group spread across three+ continents.