StarFISH is a suite of programs designed to determine the star formation history (SFH) of a stellar population, given multicolor stellar photometry and a library of theoretical isochrones. It constructs a library of synthetic color-magnitude diagrams from the isochrones, which includes the effects of extinction, photometric errors and completeness, and binarity. A minimization routine is then used to determine the linear combination of synthetic CMDs that best matches the observed photometry. The set of amplitudes modulating each synthetic CMD describes the star formation history of the observed stellar population.

References:

• A Method for Determining the Star Formation History of a Mixed Stellar Population,
  Harris and Zaritsky, 2001 ApJS 136 25

• StarFISH User's Manual Jason Harris

StarFISH in the Literature: Some published work that has used StarFISH:

• Brown et al. (2003): Evidence of a Significant Intermediate-Age Population in the M31 Halo from Main-Sequence Photometry

• Harris & Zaritsky (2004): The Star Formation History of the Small Magellanic Cloud

• Barker et al. (2004): Variations in Star Formation History and the Red Giant Branch Tip

The latest version is 1.1-p1, which was released on 2 June 2004. There are two tarballs. Both contain the StarFISH source code and auxiliary programs and scripts, as well as the user manual. Both also include the latest Padua isochrones (note that StarFISH should work with nearly any modern isochrones). The full version adds a sample parsed isochrone library, and a sample synthetic CMD library.

• Full version: SFH-1.1-p1.tar.gz (33 MB)
• Compact version: SFH-1.1-p1.compact.tar.gz (4.7 MB)

I have created some message boards for the StarFISH community. Post early, post often!

StarFISH Message Board

This release fixes a number of bugs in SFH-1.1:

• missing "char()" in grid/mkgrid.f caused compile error
• missing "epix" factor in synthcode/dmags.f caused inflated model phot. errs. in y-direction
• using binary-search loop in synthcode/dmags.f which makes synth run much faster
• bug in sfhcode/dchi.f made error bars much too large
• synthcode/crowd.f did not check the value of "interp_err"
• Some variables declared "character*24" should have been "character*40"

If you already have downloaded SFH-1.1, you can simply download this small patch file. Apply the patch like this:

1. cd to your SFH directory
2. type the following command: patch -p1 < /path/to/patchfile
3. recompile all code

Some of the new features include:

• Option to use Poisson fitting statistic instead of chi-squared
• Option to hold selected amplitudes constant at specified values
• Option to use an analytic phot. error model rather than artificial stars tests
• More flexible parsing of input files and file names
• Fixed periodicity in random-number generator that led to overly-noisy synth. CMDs.
• New code to interpolate between similar isochrones
• Updated manual
• The sfh.sm plotting script, and the mkimages scripts, are much more usable now.

Jason Harris
Steward Observatory
933 N. Cherry Ave.
Tucson, AZ 85721
520-621-5923
jharris()as!arizona!edu (address obfuscated to thwart spambots)
http://marvin.as.arizona.edu/~jharris