[AstroPy] ESA Summer of Code in Space 2013

Joe Harrington jh@physics.ucf....
Thu Jun 20 04:31:37 CDT 2013


It sounds like we're on the same wavelength (sorry) regarding the
interface, and yes, from the state you describe writing something to
last from the ground up or from some basic workhorse routines sounds
like a good idea.

>> temperatures vs. depth.  In other words, will it calibrate the spectrum
>> or reproduce it with a model?
>
> I don't think that there is a general consensus on this, but in my view, 
> the question
> must be which tasks make sense to do from the command line and which 
> ones will be made significantly easier
> by means of a GUI, and implementing them in that order. I always shun 
> from software that makes me set everything through
> point-and-click, file choosing dialogs etc., when it could be done 
> easier by CLI.
> Reading a line list from a file should be a no-brainer from the command 
> line, and possibly, a good
> fitting package would provide a few convenience functions for loading 
> data and line lists into the appropriate data structures.

So, I think we're misconnecting here.  To me a line list has some
hundreds of millions of lines, and you'd never put it in a text file.
What kind of spectra are you thinking of fitting?  Is each feature a
single transition, like stellar UV atomic lines, or does each feature
integrate huge numbers of transitions, like in NIR planetary/brown dwarf
spectra?  It sounds like you are separately fitting each feature to a
Voigt, rather than broadening and integrating, say, all the methane
lines, then scaling the result to the data to derive a methane column
abundance.  Or are you thinking of both applications?  The reason it
matters now is that some designs that do the simple situation well might
not be easily adapted to the complex one.

FWIW, my group is working on a radiative transfer program for
exoplanetary emission and absorption, along with a DE-MCMC fitting
routine.  The basic RT code and MCMC are working and are OSS, though not
yet on github.  If you do go to the point of fitting molecular spectra
to get abundances, the RT code (written in C and depending on just the
GSL, I think) might be what you need.  The DE-MCMC is Python (it might
have some low-level C, I'm not sure, but if so it doesn't depend on
anything beyond libc).  Let me know if you want these.

--jh--


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