  We present low-temperature specific heat of the electron-doped
Ba(Fe$_{0.9}$Co$_{0.1}$)$_{2}$As$_{2}$, which does not show any indication of
an upturn down to 400 mK, the lowest measuring temperature. The lack of a
Schottky-like feature at low temperatures or in magnetic fields up to 9 Tesla
enables us to identify enhanced low-temperature quasiparticle excitations and
to study anisotropy in the linear term of the specific heat. Our results can
not be explained by a single or multiple isotropic superconducting gap, but are
consistent with multi-gap superconductivity with nodes on at least one Fermi
surface sheet.
