The Formation of Dark Matter Halo and Photon Decoupling

This paper aims to establish a unified theoretical framework illustrating the joint effect of the evolution of dark matter halo formation and baryon-photon decoupling on the initial conditions of cosmic structure formation during recombination. The event and mechanism during the period 1100<z<3400 are briefly concluded tthrough the analytical modelling of Jeans instability in expanding spacetime, Top-Hat spherical and ellipsoidal collapse simulations, and Boltzmann transport solutions for recombination kinetics. The paper mainly highlights the dark matter virilization dynamics and the mechanism of recombination, emphasizing their roles in establishing the large-scale structure.