Forward ${\mathit{K}}^{+}$ Production in Subthreshold $\mathit{pA}$ Collisions at 1.0 GeV

$K^{+}$-meson production in $\mathrm{pA}$ ( $A=\mathrm{C},\mathrm{Cu},\mathrm{Au}$) collisions has been studied using the ANKE spectrometer at an internal target position of the COSY-Jülich accelerator. The complete momentum spectrum of kaons emitted at forward angles, $\vartheta \le 12°$, has been measured for a beam energy of $T_p=1.0\mathrm{}\mathrm{GeV}$, far below the free $\mathrm{NN}$ threshold of 1.58 GeV. The spectrum does not follow a thermal distribution at low kaon momenta and the larger momenta reflect a high degree of collectivity in the target nucleus.