Abstract Using the ballistic approximation accretion flow model, this paper investigates the shadow and polarization images of a Kerr-like black hole surrounded by a cold dark matter halo. By numerically solving the geodesic and radiative transfer equations, we analyze the effects of the critical density rc r c, the scale radius of the dark matter halo rₛ r s, the spin parameter a, and the observer inclination ₒ θ o on the resulting images. In all cases, a bright ring structure corresponding to higher-order images is observed, accompanied by an inner region of decreased intensity. The results show that both rc r c and rₛ r s increase the size of the higher-order images, while the spin parameter a and inclination ₒ θ o modify the image morphology, producing a crescent-shaped bright region on the left side. In the polarization maps, the linear polarization degree Pₒ P o is significantly lower in the higher-order image region, and the polarization vectors exhibit distinct distributions inside and outside the ring. Compared with the thin disk model, the thick disk model displays notable differences in both shadow and polarization images.
Zeng et al. (Sun,) studied this question.