PUB - Publikationen an der Universität Bielefeld

If dark matter is made up of Weakly Interacting Massive Particles, the annihilation of these particles results in partial ionization and heating before the formation of the first stars. We investigate the effect of gas heating on the expected Hydrogen 21cm power spectrum. Heating by particle annihilation results in a minimum in the power spectrum of 21cm fluctuations at the redshift at which the gas temperature equals the CMB temperature. Such a minimum is not expected in the standard theory since the gas temperature in the absence of luminous sources or dark matter heating is always below the CMB temperature. Thus observations of the Hydrogen 21cm power spectrum at multiple redshifts may help us obtain constraints on dark matter particle and halo properties.