I have been trying to overplot contour of [Fe/H] on top of a projected density plot,
but I get strange errors (apparently due to unit mismatch). I was wondering if there is a way
to do this. All I need is to divide projected metal density by projected density, save it, and plot its contour. How do you do this with YT?

Thank you very much!

Mohammadtaher Safarzadeh, Ph.D.