Probability density for a hyperbolic SPDE with time dependent   coefficients
  We prove the existence and smoothness of density for the solution of a hyperbolic SPDE with free term coefficients depending on time, under hypoelliptic non degeneracy conditions. The result extends those proved in Cattiaux and Mesnager, PTRF 2002, to an infinite dimensional setting. 
Marta Sanz-Sol\'e and Iv\'an Torrecilla-Tarantino