Imfit is an open-source C++ program for fitting models to astronomical images (primarily of galaxies). It is fast, flexible, and designed to be easily extended with new functions for components of the model image.
Examples of Use:
Fitting an image (with a model specified in the configuration file
$ imfit someimage.fits --config model_description.txt
Fitting a subsection of the image and convolving the model with a Point-Spread-Function image, using Differential Evolution as the solver:
$ imfit someimage.fits[500:750,600:800] --config model_description.txt --psf psf.fits --de
Markov Chain Monte Carlo (MCMC) analysis of the same image and model:
$ imfit-mcmc someimage.fits[500:750,600:800] --config model_description.txt --psf psf.fits
imfit -h– lists command-line flags and options
imfit --list-functions– lists all available image functions for models
imfit --list-parameters– lists the individual parameters for all image functions
imfit --sample-config– writes a sample configuration file to the current directory
The main documentation for Imfit is in the PDF file imfit_howto.pdf.
Where to Get It:
Pre-compiled binaries for Linux and macOS, along with the source code for compilation, are available here.
The full source-code distribution is available at Imfit’s Github page.
- Getting Started with Imfit: Tutorial
- Fitting Your First Image
- Inspecting the Fit: Model Images and Residuals
- Better Fits: Telling Imfit the Truth About the Image
- Better Fits: Masking
- Better Fits: Trying Different Models
- More Correct Fits: PSF Convolution
- Chi-Squared and All That: Using Different Fit Statistics
- Parameter Uncertainties and Correlations: Bootstrap and MCMC
- Configuration File Format
- General Notes and Advice for Fitting Images
- How to Write New Image Functions