  The problem of sending two correlated vector Gaussian sources over a
bandwidth-matched two-user scalar Gaussian broadcast channel is studied in this
work, where each receiver wishes to reconstruct its target source under a
covariance distortion constraint. We derive a lower bound on the optimal
tradeoff between the transmit power and the achievable reconstruction
distortion pair. Our derivation is based on a new bounding technique which
involves the introduction of appropriate remote sources. Furthermore, it is
shown that this lower bound is achievable by a class of hybrid schemes for the
special case where the weak receiver wishes to reconstruct a scalar source
under the mean squared error distortion constraint.
