H₂ Cooling and Gravitational Collapse of Supersonically Induced Gas Objects

We study the formation and gravitational collapse of supersonically induced gas objects (SIGOs) in early universe. run cosmological hydrodynamics simulations SIGOs, including relative streaming motions between baryons dark matter. Our also follow nonequilibrium chemistry molecular hydrogen cooling primordial clouds. A number SIGOs are formed with fast-streaming 2 times rms velocity fluctuations. identify a particular cloud that condensates by H$_2$ without being hosted matter halo. The SIGO remains outside virial radius its closest halo, it becomes Jeans unstable when central gas-particle density reaches $\sim 100~{\rm cm}^{-3}$ temperature $\sim$ 200 K. corresponding mass is 10^5 M_{\odot}$, thus stars or star cluster expected SIGO.