Supernova Explosions in the Early Universe: Evolution of Radiative Remnants and the Halo Destruction Efficiency

We study the evolution of supernova (SN) remnants of the first stars, taking proper account of the radiative feedback of the progenitor stars on the surroundings. We carry out a series of one-dimensional hydrodynamic simulations with radiative cooling, starting from initial configurations that are drawn from the results of our earlier radiation hydrodynamic simulations of the first HII regions. In low-mass (< 10^6 M_sun) halos, the stellar radiation significantly reduces the ambient gas density prior to the SN explosion. The blastwave quickly propagates over the halo's virial radius, leading to complete evacuation of the gas even with the input energy of 10^50 erg. We find that a large fraction of the remnant's thermal energy is lost in 0.1-10 Myr by line cooling, whereas, for larger explosion energies, the remnant expands even more rapidly with decreasing interior density, and cools predominantly via inverse Compton process. In higher mass halos, the gas density near the explosion site remains high and the SN shock is heavily confined; the thermal energy of the remnant is quickly radiated away by free-free emission, even if the total input energy exceeds the binding energy of halos by two orders of magnitude. We show that the efficiency of halo destruction is determined not only by the explosion energy but also by the gas density profile, and thus controlled by radiative feedback prior to the explosion. Several implications of our results for the formation of first quasars and second-generation stars in the universe are also discussed.