  We consider asymptotically anti-de Sitter spacetimes in three-dimensional
topologically massive gravity with a negative cosmological constant, for all
values of the mass parameter $\mu$ ($\mu\neq0$). We provide consistent boundary
conditions that accommodate the recent solutions considered in the literature,
which may have a slower fall-off than the one relevant for General Relativity.
These conditions are such that the asymptotic symmetry is in all cases the
conformal group, in the sense that they are invariant under asymptotic
conformal transformations and that the corresponding Virasoro generators are
finite. It is found in particular that at the chiral point $|\mu l|=1$ (where
$l$ is the anti-de Sitter radius), one must allow for logarithmic terms (absent
for General Relativity) in the asymptotic behaviour of the metric in order to
accommodate the new solutions present in topologically massive gravity, and
that these logarithmic terms make both sets of Virasoro generators non-zero
even though one of the central charges vanishes.
