We show that the thermal Sunyaev-Zeldovich effect caused by hot electrons in the Local Supercluster ( LSC ) can explain the abnormal quadrupole and octopole of the cosmic microwave background ( CMB ) that were measured by WMAP and COBE .
The distortion needed to account for the low observed quadrupole is a spot in the direction of the LSC with a temperature decrease of order \Delta T \approx - 7 \mu K for \nu \sim 20 — 90 Ghz photons .
The temperature and density of the hot gas which can generate such an effect are consistent with observations of the X-ray background .
If this hypothetic foreground is subtracted from the WMAP data , we find that the amplitude of the quadrupole ( \ell = 2 ) is substantially increased , and that the “ planarity ” of both the quadrupole and the octopole ( \ell = 3 ) are weakened .
For smaller scales the effect decays and , at least in our simplified model , it does not affect the angular power spectrum at \ell > 10 .
Moreover , since the Sunyaev-Zeldovich effect increases the temperature of photons with frequencies above 218 GHz , observations sensitive in that range ( such as PLANCK ’ s HFI ) will be able to confirm whether the LSC indeed affects the CMB .