  The expression for the dynamical spectral structure of the density
fluctuation near the QCD critical point has been derived using linear response
theory within the purview of Israel-Stewart relativistic viscous hydrodynamics.
The change in spectral structure of the system as it moves toward critical end
point has been studied. The effects of the critical point have been introduced
in the system through a realistic equation of state and the scaling behaviour
of various transport coefficients and thermodynamic response functions. We have
found that the Brillouin and the Rayleigh peaks are distinctly visible when the
system is away from critical point but the peaks tend to merge near the
critical point. The sensitivity of structure of the spectral function on wave
vector ($k$) of the sound wave has been demonstrated. It has been shown that
the Brillouin peaks get merged with the Rayleigh peak because of the absorption
of sound waves in the vicinity of the critical point.
