cconroy20 / fsps

Flexible Stellar Population Synthesis
MIT License
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Dust parameters : opacity, optical depth, or Av ? #35

Closed zychen-astro closed 4 years ago

zychen-astro commented 6 years ago

Hello, I am a little confused about the dust parameters settings and how to set/obtain dust reddening in Av.

The documentation says :

dust2 Dust parameter describing the attenuation of old stellar light, i.e. where $t >dust_tesc$ (for details, see Conroy et al. 2009a). Specifically, it is the opacity at 5500˚ A. $Default value is 0.0$.

I am a little confused about the statement here. Should the opacity here be optical depth? (Because $\tau = \int \kappa \rho dx$, and it is $\tau$ that is directly linked with Av, or extinction in magnitude.)

And can I get Av values directly from the code or I need to calculate it myself?

Forgive me if the question seems to be silly. I am not very familiar with the code. I am mainly concerned with is the magnitude, Av and colors of galaxies in my current work.

Thank you.