Ionization by early quasars and Cosmic Microwave Background anisotropies

We discuss the photoionization of the intergalactic medium by early formed quasars and propose a mechanism which could generate measurable temperature fluctuations $\delta_{T }~=~\Delta T/T$ of the cosmic microwave background (CMB). Early quasars produce individual ionized regions around themselves. We evaluate both thermal and kinetic (first-order Doppler) Sunyaev-Zeldovich (SZ) effects associated with those ionized regions.