  We discuss the relevance, for the search of gravitational-wave bursts, of
upper limits on the total mass loss of the Galaxy which come from various
astronomical observations. For sub-millisecond bursts we obtain limits on the
event rate, as a function of the GW amplitude, which are stronger than the
corresponding upper limits set by LIGO in the S2 run. A detection of a burst
rate saturating these limits, with the sensitivities of present and near-future
runs, would imply that, with some improvement on the accuracy of astronomical
observations of the Galaxy, as foreseen with the GAIA mission, it might be
possible to detect gravitational waves indirectly from their effect on galactic
dynamics.
