Dark matter annihilation feedback: Effects upon collapse and fragmentation

We perform the first 3D simulations to include the effects of dark matter annihilation (DMA) in a calculation of the collapse of a primordial halo to near stellar densities. We couple the DMA to a time dependent chemical network, and include the effects of DMA induced ionisation. Despite an increase in the temperature of the halos, the gas temperature cannot rise above 2000 K due to cooling from H2 dissociation, and a normal Population III star forms at the centre. After the first star forms, the increased temperatures in the disk suppress further fragmentation. In our two simulated halos, fragmentation is suppressed completely in one, and only one secondary protostar forms in the second. However it is possible that in the future the baryons could become displaced from the dark matter peak and these effects could be reduced. © 2012 American Institute of Physics