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bd-j / prospector

Python code for Stellar Population Inference from Spectra and SEDs
http://prospect.readthedocs.io
MIT License
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Question: Dust Attenuation in SF regions #199

Closed oconnorb closed 3 years ago

oconnorb commented 3 years ago

Hello,

I am curious as to the proper method to account for additional dust attenuation in star forming regions. Is there an implementation of dust in nebular regions within prospector? I found reference to this in Section 3.1.3 of Leja et al. 2017 (https://iopscience.iop.org/article/10.3847/1538-4357/aa5ffe/pdf), but I have not found a description of the method for this in the docs.

Thank you, Brendan O'Connor

bd-j commented 3 years ago

Hi, this is controlled by the 'dust1' parameter. The FSPS manual has more details and references.

You can add "dust1" to the parameter set, either fixed or free, e.g.

model_params["dust1"] = dict(N=1, isfree=True, init=0.0, prior=prospect.models.priors.TopHat(mini=0, maxi=1.0))

In Leja et all the value of "dust1" is tied to the value of "dust2" via a new parameter and parameter transformation

model_params["dust1"]  = {"N": 1, "isfree": False, 'depends_on': prospect.models.transforms.dustratio_to_dust1,
                          "init": 0.0, "units": "optical depth towards young stars"}
model_params["dust_ratio"] = {"N": 1, "isfree": True, 
                              "init": 1.0, "units": "ratio of birth-cloud to diffuse dust",
                              "prior": priors.ClippedNormal(mini=0.0, maxi=2.0, mean=1.0, sigma=0.3)}

Hope this helps.

oconnorb commented 3 years ago

Thank you very much. The FSPS manual is very helpful, as are your comments on how to tie dust1 and dust2.