Extinction curves that extend below 912 A

[karllark]

BEAST runs interested in providing predictions of ionizing photons need dust extinction curves that extend below 912 A. This PR provides two new dust extinction models that merge observation based extinction curves with dust grain models to provide this capability.

This is done using the Generalized_DustExt capabilities and models available in the dust_extinction package. Previously this capability was provide directly inside of the Gordon16_RvFALaw using static data files.

In the beast_settings.txt file, these new extinction models can be used by declaring the extinction mixture model to be:

extlaw = extinction.Generalized_RvFALaw(ALaw=extinction.Generalized_DustExt(curve=’F19_D03_extension’), BLaw=extinction.Generalized_DustExt(curve=’G03_SMCBar_WD01_extension’))

Replaces #749.

[karllark]

Still need to remove the old draine_extend code and add docs. And maybe a quick test.

[codecov-commenter]

Codecov Report

Merging #767 (5add070) into master (bf9ed7a) will increase coverage by 0.29%. The diff coverage is 83.87%.

@@            Coverage Diff             @@
##           master     #767      +/-   ##
==========================================
+ Coverage   42.84%   43.14%   +0.29%     
==========================================
  Files         102      103       +1     
  Lines        9928     9961      +33     
==========================================
+ Hits         4254     4298      +44     
+ Misses       5674     5663      -11     

Impacted Files	Coverage Δ
beast/physicsmodel/dust/extinction.py	90.04% <50.00%> (+6.10%)	:arrow_up:
beast/physicsmodel/dust/extinction_extension.py	92.00% <92.00%> (ø)

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[karllark]

Plots showing the extended extinction curves compared to the grain models can be seen in the API docs via the RTD build for this PR.

https://beast--767.org.readthedocs.build/en/767/api/beast.physicsmodel.dust.extinction_extension.F19_D03_extension.html#beast.physicsmodel.dust.extinction_extension.F19_D03_extension

and

https://beast--767.org.readthedocs.build/en/767/api/beast.physicsmodel.dust.extinction_extension.G03_SMCBar_WD01_extension.html#beast.physicsmodel.dust.extinction_extension.G03_SMCBar_WD01_extension

[cmurray-astro]

Gold star indeed! Thanks, Karl! This looks good to me. Reading the new docs I wonder if there is a/what is the drawback to defaulting to the "extension" models in general (i.e., even without sub-912A observations)?

[galaxyumi]

Hooray. Thanks Karl to make this functionality generic and self-contained eventually! So now the default is for users to indicate whether they want to use an extended version or not in their beast_settings.txt file, right?

[karllark]

Gold star indeed! Thanks, Karl! This looks good to me. Reading the new docs I wonder if there is a/what is the drawback to defaulting to the "extension" models in general (i.e., even without sub-912A observations)?

Yes. The grain model is smoothly merged with the observational model starting at 1675 A. So, the extinction curve in the FUV is changed from what the observations are saying.

[karllark]

Hooray. Thanks Karl to make this functionality generic and self-contained eventually! So now the default is for users to indicate whether they want to use an extended version or not in their beast_settings.txt file, right?

Yes.

I am hoping you can try out this new capability and see if it works as you expected.

[karllark]

Gold star indeed! Thanks, Karl! This looks good to me. Reading the new docs I wonder if there is a/what is the drawback to defaulting to the "extension" models in general (i.e., even without sub-912A observations)?

Yes. The grain model is smoothly merged with the observational model starting at 1675 A. So, the extinction curve in the FUV is changed from what the observations are saying.

I've added a bit more documentation to explain this point.

[karllark]

Gold star = code, tests, and docs. Trying to encourage such PRs. ;-)

[karllark]

Still looking for a formal review of this PR when one of you has the time.