A Code for Modeling Asymmetries in Disk Galaxies


DiskFit is a code for modelling asymmetries in either photometry (fitting images) or kinematics (fitting velocity fields) of disk galaxies. For velocity field fits, DiskFit is an extension of Velfit 2.0, first presented in Spekkens & Sellwood (2007), and improved in Sellwood & Sanchez (2010). For images, DiskFit is an extension of the algorithm presented by Reese et al. (2007). Both the photometric and kinematic branches of DiskFit employ the same basic minimization technique, originally described by Barnes & Sellwood (2003). The application of DiskFit to the photometry and kinematics of a nearby galaxy is illustrated in Kuzio de Naray et al. (2012).The most recent description of the code is in Sellwood & Spekkens (2015).

To download the DiskFit executable, click on the link appropriate for your architecture from the table below (Mac users: you want "Darwin"). To download example files as well as the source code, click on the link in that same table. The examples and source code are bundled as a tarball. To extract them, type:

    gunzip DiskFit1.2.2.source.tar.gz

    tar xvf DiskFit1.2.2.source.tar

The package contains directories containing example data, and a directory containing some source code.

Finally, the Bootlace utility is useful for deriving uncertainties from bootstrap realizations done using several independent DiskFit runs: it is bundled with the source code, and can be dowloaded as an executable under the `Bootlace' column below.

Disclaimer: DiskFit is free software and comes with ABSOLUTELY NO WARRANTY. It is distributed under the GNU General Public License. This implies that the software may be freely copied and distributed. It may also be modified as desired, and the modified versions distributed as long as any changes made to the original code are indicated prominently and the original copyright and no-warranty notices are left intact. Please read the General Public License for more details. Note that the authors retain the copyright to the code and documentation.


Version Date DiskFit Executable Source + Examples Bootlace Executable Documentation Comments
1.2.2 August 2017 Darwin

Linux (64-bit)
Source Darwin

Linux (64-bit)
User's manual (pdf) Bug fixes for bar PA and bulge on photometric side.
Biweight used to compute uncertainties instead of standard deviations.
*.csv file output for covariance plots.
1.2.1 May 2016 Darwin

Linux (64-bit)
Source Darwin

Linux (64-bit)
User's manual (pdf) Bug fix for 64-bit FITS file input/output.
1.2 September 2015 Darwin

Linux (64-bit)
Source Darwin

Linux (64-bit)
User's manual (pdf) What's new: Dynamically allocated arrays
Mask and uncertainty file can be input in photometric branch
Seeing/beam smearing bug corrected
Minor bug fixes and modifications. See documentation for details.
1.1 May 2013 Darwin

Linux (64-bit)
Source Darwin

Linux (64-bit)
User's manual (pdf) Minor bug fixes and modifications. See documentation for details.
What's new: DiskFit now handles FITS files with 64-bit reals.
1.0 September 2012 Darwin

Linux (64-bit)
Source Darwin

Linux (64-bit)
User's manual (pdf) First release.



The sources of documentation for DiskFit are related articles papers (Spekkens & Sellwood 2007, Sellwood & Sanchez 2010 for kinematic fits, and Reese et al. (2007) for photometric fits, and Sellwood & Spekkens 2015), and the user's manual. The manual instructions assume that you have read the papers and are familiar with their notation.


Please cite the relevant papers if you use DiskFit in your research.


We are happy to answer questions about the code, and we welcome comments and suggestions. Please send an email to kristine.spekkens**at**gmail.com.


This material is based upon work supported by the National Science Foundation, and by the National Sciences and Engineering Council of Canada.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation or the National Sciences and Engineering Research Council of Canada.

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Last modified: Fri Aug 18 13:52:17 EDT 2017