  In this article, we consider the stochastic wave and heat equations driven by
a Gaussian noise which is spatially homogeneous and behaves in time like a
fractional Brownian motion with Hurst index $H>1/2$. The solutions of these
equations are interpreted in the Skorohod sense. Using Malliavin calculus
techniques, we obtain an upper bound for the moments of order $p\geq2$ of the
solution. In the case of the wave equation, we derive a Feynman-Kac-type
formula for the second moment of the solution, based on the points of a planar
Poisson process. This is an extension of the formula given by Dalang, Mueller
and Tribe [Trans. Amer. Math. Soc. 360 (2008) 4681-4703], in the case $H=1/2$,
and allows us to obtain a lower bound for the second moment of the solution.
These results suggest that the moments of the solution grow much faster in the
case of the fractional noise in time than in the case of the white noise in
time.
