Radiation Hydrodynamics with HMCS CP-PACS: Hydrodynamics + Radiation GRAPE-6 : Gravity Computer Physics Method SPH (Smoothed Particle Hydrodynamics) Hydrodynamics CP-PACS Radiation Radiative Transfer Solver GRAPE- 6 Self-Gravity Direct Summation SPH  Superposition of extended karnels  Full Lagrange method in 3D Radiative Transfer Solver P1 P2 Source Target E1 E2 E3 E4 E5 P3 P4 P5

Radiation Hydrodynamical Simulation on Galaxy Formation Cosmic Time 3D Radiation SPH Calculation Big Bang 10-44 sec Results  Elliptical galaxies forms under strong UV  Spiral galaxies forms under Cosmic Recombination 0.1Myr Weak UV Cosmic Reionization 0.5Gyr Initial Strong UV Initial Galaxy Formation 2Gyr Final Final White dots are stars and red dots are ionized gas. 15Gyr (Present Day)