The ornamental design for the “bow hanger”, as shown and described.
FIG. 1 is an oblique view of the bow hanger and hook showing my new design deployed on a tree, which is shown in broken lines and understood to form no part of the claimed design;
FIG. 2 is an oblique view partially folded;
FIG. 3 is an oblique view folded;
FIG. 4 is a top view of the bow hanger and hook;
FIG. 5 is a left side view of the bow hanger, the right side view being symmetrical, and hook;
FIG. 6 is a bottom view of the bow hanger and hook;