add keyword argument to specify voigt fit to top of spectrum

[Munazza Alam]

Add keyword argument that allows users to specify if wings of Voigt profile will be fit to the highest point in the data. By default, this module seems to fit to the average of the spectrum outside of the absorption line.

[Adam Ginsburg]

I don't understand the request - it sounds you want the voigt profile to fit just one of the data points outside of some set range? I think the feature you're actually describing is continuum fitting, which is implemented in pyspeckit under the name "baseline". The continuum has to be fit separate from the profile, i.e. it is a separate model.

[Adam Ginsburg]

OK, after reading your e-mail, I understand that this is an option often provided by IDL codes - could you post links to some for reference? I've never used such a feature myself and therefore have no idea how to implement such a thing at the moment.

[Munazza Alam]

I got this IDL routine from advisor: https://www.dropbox.com/s/9p7rwlk9ah8yosg/contf.pro. The code actually fits the top by default, but has a keyword (bot) to fit the bottom. Also, a former member of my research group used Sherpa (http://cxc.harvard.edu/sherpa3.4/) as his spectral line analysis tool. This package has a keyword argument that allows users to specify an upper wavelength limit. You can find his blog posts and output plots here: http://www.bdnyc.org/tag/sherpa.

[Adam Ginsburg]

OK, thanks.

I can't implement this feature any time in the immediate future due to travel; if you want to add it I'd welcome a pull request.