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dnarayanan / powderday

powderday dust radiative transfer
BSD 3-Clause "New" or "Revised" License
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Output in the observation-frame #90

Closed astroferreira closed 4 years ago

astroferreira commented 4 years ago

Is there a way to define the the distance to the object in the configuration files? If not, is it difficult to achieve something like that?

I would like, for example, with the same filter get a rest-frame and a observation-frame image.

dnarayanan commented 4 years ago

Hi, thanks for checking it out!

We didn't put a redshift in the config files (other than implicitly via the TCMB) in part to keep things as flexible as possible. This said, if you'd like a rest and observation frame, it's possible to set this up manually by forcing your filters to be at the redshift you'd want them to be at. For example, if you wanted something like the J_2mass.filter at the rest frame and at some redshift, you could specify the J_2mass.filter in the parameters_master file, and then create a new filter that was basically the exact same, but with the wavelengths multiplied by the (1+z) that you wanted.

I will leave this open though since this represents an enhancement that would be straight forward to address. One could imagine in the text subsequent to line 259 to put something that redshifts the filters there. Though I'm not 100% sure yet if this makes more sense, or giving the user the ultimate control by just setting up dummy filters at the redshift of their interest makes more sense. Thoughts definitely welcome!

astroferreira commented 4 years ago

Thank you @dnarayanan.

I also checked that you can set a distance to hyperion ModelOutput get_image() method, which should account for cosmological dimming. I agree that having ultimate control should be better, it is just different from someone used to having the instrument properties in the SKIRT setup ski files.