sedFit

It is important to note right away this is proprietary, unreleased software, with Caltech scientist Andy Boden as the author and principal investigator for sedFit. As such, at the present, any scientific efforts that result from use of sedFit entitle Andy to right of authorship as a minor contributing author. For these efforts involving PTI and CHARA, however, Andy has expressed a specific interest in supporting these scientific investigations with sedFit (noting this condition).
 * sedFit Information** **(Terms & Conditions)**

Useful link: the Lowell LARI-BGBF sedfit wiki

sedFit is a spectral energy distribution fitting program. It takes photometry, both broad- and narrow-band (and all flavors inbetween) and attempts to fit a spectral template to those photometric data points. sedFit can work with spectra as well, insofar that spectra really are just a wavelength series of extremely narrowband photometry.
 * what does sedFit do?**

//Important safety tip//: sedFit runs using [|octave] ; however, newer versions of octave seem to not play well with sedFit. It currently runs on the Ubuntu shell using octave 2.1.73 ; octave 2.9 and later does not appear to work with sedFit.

sedFit is flexible and will take pretty much any spectral template you throw at it. Currently the empirical templates of [|Pickles (1998)] are the favorite in that they are empirical templates - no model dependence. Model templates are allowable, however, if one so desires, so such things as NexGen, Phoenix, Kurucz, etc. area all allowable.
 * Input templates for <span style="font-family: 'Courier New',Courier,monospace;">sedFit **

<span style="font-family: 'Courier New',Courier,monospace;">sedFit is usually invoked with a command line structure that involves: code $ sedFit [spectral template file] [photometry file] code Additionally, there are some nifty tools embedded in getCal which will automatically collect a lot of this photometry for you. This is very useful if you're wrestling with a lot of stars. In practice, this can be quite messy: code $ ~/mscSoftware/bin/fbolFormat -strom -geneva -2Mass -longWL HD217014 > HD217014.phot $ ~/develop/sed/sedFit ~/mscSoftware/data/catalogs/pickles/data/main_sequence/ukg2iv.dat HD217014.phot code Details on photometry files is available, including the nifty python script <span style="font-family: 'Courier New',Courier,monospace;">GCPD2.py and its supporting wrapper shell script <span style="font-family: 'Courier New',Courier,monospace;">getAllPhotometry.batx.
 * Command line invocation of <span style="font-family: 'Courier New',Courier,monospace;">sedFit **

Alexa Hart wrote some notes on that may be of use to you as well.

There are a few very useful command line options: <span style="font-family: 'Courier New',Courier,monospace;">-AV //[value]// : tells <span style="font-family: 'Courier New',Courier,monospace;">sedFit to impose a reddening value AV <span style="font-family: 'Courier New',Courier,monospace;">-fitAV : tells <span style="font-family: 'Courier New',Courier,monospace;">sedFit to iterate on a reddening value until it finds a best fit AV. Gives an error bar on AV as well (very useful!). Important safety tip: this option can be **very** time consuming (eg. ~10 minutes to run the code). This can be reduced by using <span style="font-family: 'Courier New',Courier,monospace;">-fitAV and <span style="font-family: 'Courier New',Courier,monospace;">-AV together and providing a good initial guess for AV.
 * Command line options**

<span style="font-family: 'Courier New',Courier,monospace;">sedFit will report the following values for the best fit of the photometry to the template: a chi^2 per degree of freedom value, an estimate of the bolometric flux of the source (both before and after reddening), a diameter estimate, and (if indicated, see below) a reddening value. What <span style="font-family: 'Courier New',Courier,monospace;">sedFit does **NOT** fit is template temperature: this is a **fixed value** associated with the template that goes into the fit and is used to extract an angular size estimate from the process.
 * Output of <span style="font-family: 'Courier New',Courier,monospace;">sedFit **

These values are reported textually on the command line window, but of some additional interest is the graphic output: a postscript file is generated detailing the fit. Here are some examples (a fairly boring G0IV star) and  (a moderately distant M giant with some reddening).