Cooling of Population III objects in a pressure supported collapse

The cooling and collapse of Population III objects is investigated in the framework of 'flat' standard cosmological model. It is assumed that the significant component of fluctuations was isothermal and that the cooling of the collapsing cloud was due to the H2 molecule. The pressure inside the cloud has been taken into account. The only parameter in the models is the cloud's mass. The numerical solutions show that the first bound systems were of about a million solar masses. In the range of 105 - 107 solar masses there are four different modes of the behaviour of the cloud's radius, depending on the mass. It is suggested that the different ways to collapse gave rise to different fragmentation processes and hence to different star systems with a similar mass. (author)