  We have investigated the low-energy electronic structure of the heavy fermion
superconductor CeCoIn5 by angle-resolved photoemission. We focus on the
dispersion and the peak width of the prominent quasi-two-dimensional Fermi
surface sheet at the corner of the Brillouin zone as a function of temperature
along certain k-directions with a photon energy of hn = 100 eV. We find slight
changes of the Fermi vector and an anomalous broadening of the peak width when
the Fermi energy is approached. Additionally we performed resonant ARPES
experiments with hn = 121 eV. A flat f-derived band is observed with a distinct
temperature dependence and a k-dependent spectral weight. These results,
including both off- and on-resonant measurements, fit qualitatively to a two
level mixing model derived from the Periodic Anderson Model.
