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Flexible Stellar Population Synthesis
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ISOCHRONES changed BPASS wavelength grid; extrapolated SSPs Jul 15, 2018
OUTPUTS changed BPASS wavelength grid; extrapolated SSPs Jul 15, 2018
SPECTRA updated WMB models Feb 17, 2017
doc updated manual Jul 15, 2018
nebular corrected nebular files or BPASS Jul 20, 2018
.gitignore fixed bug in new WMB models Sep 23, 2016 updated README Jul 6, 2018

FSPS: Flexible Stellar Population Synthesis

version 3.1


When using this code please cite the following papers:

  • Conroy, Gunn, & White 2009, ApJ, 699, 486
  • Conroy & Gunn 2010, ApJ, 712, 833


If you have git installed, FSPS can be obtained with the following commands:

cd /path/to/desired/location/
git clone

Otherwise download a gzipped tarball from here. Then follow the instructions at doc/INSTALL.

You should not need to update the git repository until an update is announced (which is why you need to be on the mailing list - see doc/INSTALL). If you've obtained FSPS using git then when an update is announced you will need to simply type cd $SPS_HOME; git pull and then recompile. If you have made your own edits to the FSPS files, git will attempt to gracefully merge your local version with the repository version.


Below is a brief description of the contents of the directories in the fsps root directory:

  • ISOCHRONES: Contains the isochrone tables for the BaSTI and Padova isochrone sets. The Geneva isochrones have been pasted onto the BaSTI and Padova tables for high masses (M>70Msun), and the low-mass Lyon models have been pasted on at low masses. You should not edit these files unless you know what you're doing.

  • OUTPUTS: Contains the outputs of a few example calls of the routines autosps and simple. You may wish to use this directory for all outputs of the fsps routines.

  • SPECTRA: Contains the spectral libraries, the spectrum of an A0V star used to set the Vega magnitude zero points, and a spectrum of the Sun. The BaSeL spectra (based on the Kurucz models) are in binary format, primarily to make the read in time faster and to decrease the size of the fsps download. The Hot_spectra directory contain the libraries for O stars, WR stars, and post-AGB stars, from Smith et al. 2002 and Rauch 2003, respectively.

  • data: Contains files that define the set of filters and indices used in FSPS and the tabulated imfs and sfhs if those options are set. The files in this directory are readily user editable.

  • doc: Contains the manual, revision history, and installation instructions.

  • dust: Contains the dust attenuation curves for the Witt & Gordon (2000) dust model and the dust emission spectra from the Draine & Li 2007 grain model. Also contains the circumstellar dust models from Villaume et al. 2015 and the AGN dusty torus models of Nenkova et al. 2008.

  • nebular: Contains the Cloudy lookup tables for nebular emission (both continuum and line emission) computed by Nell Byler.

  • pro: Contains IDL files for reading in the .mag, .indx, and .spec output files

  • src: Contains the source files and routines from Numerical Recipes.

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