  We present the linear response theory for an elastic solid composed of active
Brownian particles with intrinsic individual chirality, deriving both a normal
mode formulation and a continuum elastic formulation. Using this theory, we
compute analytically the velocity correlations and energy spectra under
different conditions, showing an excellent agreement with simulations. We
generate the corresponding phase diagram, identifying chiral and achiral
disordered regimes (for high chirality or noise levels), as well as chiral and
achiral states with mesoscopic-range order (for low chirality and noise). The
chiral ordered states display mesoscopic spatial correlations and oscillating
time correlations, but no wave propagation. In the high chirality regime, we
find a peak in the elastic energy spectrum that leads to a non-monotonic
behavior with increasing noise strength that is consistent with the emergence
of the `hammering' state recently identified in chiral glasses. Finally, we
show numerically that our theory, despite its linear response nature, can be
applied beyond the idealized homogeneous solid assumed in our derivations.
Indeed, by increasing the level of activity, we show that it remains a good
approximation of the system dynamics until just below the melting transition.
In addition, we show that there is still an excellent agreement between our
analytical results and simulations when we extend our results to heterogeneous
solids composed of mixtures of active particles with different intrinsic
chirality and noise levels. Our work provides a thorough analytical and
numerical description of the emergent states in a densely packed system of
chiral self-propelled Brownian disks, thus allowing a detailed understanding of
the phases and dynamics identified in a minimal chiral active systems.
