  Ultrahigh resolution angle-resolved photoemission spectroscopy with
low-energy photons is used to study the detailed momentum dependence of the
well-known nodal "kink" dispersion anomaly of Bi2Sr2CaCu2O8+{\delta}. We find
that the kink's location transitions smoothly from a maximum binding energy of
about 65 meV at the node of the d-wave superconducting gap to 55 meV roughly
one-third of the way to the antinode. Meanwhile, the self-energy spectrum
corresponding to the kink dramatically sharpens and intensifies beyond a
critical point in momentum space. We discuss the possible bosonic spectrum in
energy and momentum space that can couple to the k-space dispersion of the
electronic kinks.
