  In this paper, we have modelled the dynamical and emission properties (in the
presence of radiative losses and diffusive shock acceleration) of an observed
S-shaped radio source (2MASX J12032061+131931) due to a precessing jet. In this
regard, we have performed high-resolution 3D magnetohydrodynamic (MHD)
simulations of a precessing jet in a galactic environment. We show the
appearance of a distinct S-shape with two bright hotspots when the bow shock
region weakens over time. The formed morphology is sensitive to the parameter
selections. The increased interaction between the helical jet and the ambient
medium and the deceleration of the jet due to MHD instabilities also greatly
affect the resulting structure. Hence, kinematic models must be corrected for
these deceleration effects in order to adequately predict the precession
parameters. The synthetic spectral index map shows that the jet side and
leading edges possess relatively steeper spectral index values than the jet
ridge lines, whereas the hotspots show flat spectral index values. The jets are
also found to be highly linearly polarized (up to 76%) and the magnetic field
lines, in general, follow the jet locus which is formed due to the jet-ambient
medium interaction. Diffusive shocks, in this context, keep the structure
active during its course of evolution. Furthermore, we have demonstrated that
these galaxies deviate significantly from the equipartition approximation
leading to a discrepancy in their spectral and dynamical age.
