Radiation-induced reversal of baryonic perturbations

It is suggested, in the context of the cold dark matter cosmology (CDM), that radiation is released at redshifts between 10 and 100 by sources which, when averaged on the comoving Mpc scales, have luminosity correlated with the underlying density of matter. The radiative push could have moved the bulk of the baryons into the minima of the dark matter distribution, creating baryon-rich seeds for the structure on galactic and large scales. Moreover, on the scale on which such reversal of baryonic perturbations happens, power in the combined spectrum of density perturbations would be smaller than in the CDM universe with the same normalization on the very large scales which are opaque and therefore immune to the effects of radiation. This suggests destructive interference between baryonic and dark matter density perturbations on galactic scales as an explanation for the apparent excess of power observed on Great Attractor scales. 33 refs