Sternberg Model Fitting
By Elijah Bernstein-Cooper, March 11, 2015, 0 comments.

I successfully fit the Sternberg model to the $\Sigma_{HI}$ vs. $\Sigma_H$ relationship. I assumed that our case is a two-sided irradiation by an isotropic field, where they predict an $\Sigma_{HI}$ threshold given by

where the variables are described in the previous post.

I am fitting the $H_2$ / $HI$ ratio as a function of total gas surface density, $R_{H2}$ = $f_{H2} / f_{HI}$ where $f_{H2}$ and $f_{HI}$ are the $H_2$ and $HI$ gas fraction to the total. I solve for $\Sigma_{HI}$ as a function of $\Sigma_H$ with

Below are the fits to Taurus cores. Where only the $\alpha G$ and $\phi_{\rm CNM}$ parameters were allowed to vary in the Sternberg+14 and Krumholz+09 models, respectively. A metallicity of $Z^\prime = Z_\odot$ was assumed. I also assumed $\phi_g = 1$ for the S+14 model, and $\phi_{\rm mol} = 10.0$ for the K+09 model.

Below are Taurus fits. Find the locations of the cores in this post

Below are Perseus fits