  In this work, we present the environmental effects on wormholes residing in a
galaxy. By this, we propose that these wormholes are mimickers of supermassive
black holes residing at the galactic centers. In particular, we consider two
wormhole spacetimes classes: the Damour-Solodukhin wormhole and the braneworld
wormhole. While there is no classical matter model for the Damour-Solodukhin
wormhole, the braneworld wormhole, on the other hand, is supported by a
scalar-tensor theory on the four-dimensional brane. Intriguingly, it turns out
that the presence of a dark matter halo surrounding these wormholes can tame
the violations of energy conditions present in generic wormhole spacetimes. Our
results also demonstrate that the galactic Damour-Solodukhin wormhole is more
stable than its isolated counterpart under linear scalar perturbation, whereas
we obtain the opposite behavior for the braneworld wormhole. The perturbation
of these wormholes leads to echoes in the ringdown waveform, which are
sensitive to the properties of the dark matter halo. To be precise, the time
delay between two echoes is affected by the galactic matter environment, and it
appears to be a generic effect present for any exotic compact object living in
a galaxy. This allows us to identify the galactic parameters, independently
from the gravitational wave measurements, if echoes are observed in future
generations of gravitational wave detectors. For completeness, we have also
analyzed the impact of the galactic environment on the photon sphere, the
innermost stable circular orbits, and the shadow radius. It turns out that the
dark matter halo indeed affects these locations, with implications for shadow
and accretion physics.
