The ornamental design for a xenonlamp, as shown and described.
FIG. 1 is a front view of a xenon lamp showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a sectional view taken along lines 6-6 in FIG. 1;
FIG. 7 is a partial enlarged front view as seen from lines 7-7 in FIG. 1; and,
FIG. 8 is a partial enlarged left side view as seen from lines 8-8 in FIG. 5.
The dashed lines illustrate portions of the article that form no part of the claimed design. The dot-dash chain lines define boundaries of the claimed design that form no part thereof. Although the rear view is not shown, it is the symmetric counterpart of the front view.