The Unruh effect states an accelerated particle detector registers a thermal
response when moving through the Minkowski vacuum, and its thermal feature is
believed to be inseparable from Lorentz symmetry: Without the latter, the
former disappears. Here we propose to observe analogue circular Unruh effect
using an impurity atom in a quasi-two-dimensional Bose-Einstein condensate
(BEC) with dominant dipole-dipole interactions between atoms or molecules in
the ultracold gas. Quantum fluctuations in the condensate possess a Bogoliubov
spectrum $\omega_{\mathbf k}=c_0|{\mathbf k}|f(\hbar\,c_0|{\mathbf
k}|/M_\ast)$, working as an analogue Lorentz-violating quantum field with the
Lorentz-breaking scale $M_\ast$, and the impurity acts as an effective
Unruh-DeWitt detector thereof. When the detector travels close to the sound
speed, observation of the Unruh effect in our quantum fluid platform becomes
experimentally feasible. In particular, the deviation of the Bogoliubov
spectrum from the Lorentz-invariant case is highly engineerable through the
relative strength of the dipolar and contact interactions, and thus a viable
laboratory tool is furnished to experimentally investigate whether the thermal
characteristic of Unruh effect is robust to the breaking of Lorentz symmetry.
