I'd like to do a graph like the one below

The figure can be found in this paper
Here the x-axis scale is logaritmic up to l=30 and linear for l>30. How can I achieve something like that in python using matplotlib?
I'd like to do a graph like the one below

The figure can be found in this paper
Here the x-axis scale is logaritmic up to l=30 and linear for l>30. How can I achieve something like that in python using matplotlib?