In the standard theory of the large scale structure formation, matter accretes onto high density perturbations via gravitational instability. Collision less dark matter forms caustics around such structures, while collisional baryonic matter forms accretion shocks which then halt and heat the infalling gas. Here we discuss the characteristics. roles, and observational consequences of these accretion shocks.

• DONGSU RYU(Department of Astronomy and Space Science, Chungnam National University)
• HYESUNG KANG(Department of Earth Science, Pusan National University)