Show Categories by Author

I’m setting up a blog with two authors. One the main blog page there’s a link to both authors in the sidebar and when you click one it takes you to their author page. I have categories listed in the sidebar of these author pages but I want to restrict the categories and the posts in them to the author of the page they’re being displayed on.

I don’t see any support for this in wp_list_categories, but is there some other way of accomplishing this?