  Dense environments hosting compact binary mergers can leave an imprint on the
gravitational-wave emission which, in turn, can be used to identify the
characteristics of the environment. To demonstrate such scenario, we consider a
simple setup of binary black holes with an environment consisting of a
scalar-field bubble. We use this as a proxy for more realistic environments and
as an example of the simplest physics beyond the standard model. We perform
Bayesian inference on the numerical relativity waveforms using state-of-the-art
waveform templates for black-hole mergers. In particular, we perform parameter
estimation and model selection on signals from black-hole mergers with
different mass ratios, total mass and loudness, and hosted by scalar-field
bubbles of varying field amplitude. We find that sub-dominant gravitational
wave modes emitted during the coalescence and ringdown are key to identifying
environmental effects. In particular, we find that for face-on signals
dominated by the quadrupole mode, the environment is only detectable if both
the ringdown and the late inspiral/early merger fall in the detector band, so
that inconsistencies can be found between the inferred binary parameters and
those of the final black hole. For edge-on mergers we find that the environment
can be detected even if only the ringdown is in band, thanks to the information
encoded in the quasi-normal mode structure of the final black-hole.
