  Carrier dynamics in metallic nanostructures is strongly influenced by their
confining dimensions. Gold nanoparticles of size $\sim 2$ nm lie at the
boundary separating metallic and non-metallic behavior. In this work, we report
carrier dynamics in high aspect ratio ultrathin gold nanowires (Au-UNWs) of
average diameter $\sim$2 nm using pump (3.1 eV) and coherent white light
continuum as probe in the spectral range of 1.15 eV to 2.75 eV. The transient
carrier dynamics in Au-UNWs under extreme excitation regime is slower than
predicted by the often used two temperature model. We identify Auger-assisted
carrier heating process which slows down the hot carrier cooling dynamics. The
rate equation model fitted to the data yields an estimate of Auger coefficient
for gold nanostructures.
