In this talk I will briefly review the serendipitous discovery of a new extragalactic foreground associated with nearby Spiral galaxies and its effect on the Cosmic Microwave Background as well as current ongoing work. In recent papers we have analysed the presence of a systematic decrease in CMB temperatures around nearby large spiral galaxies pointing to an unknown interaction with CMB photons extending to megaparsec scales around these galaxies. Temperature model maps based on nearby galaxies and the Planck CMB map have a remarkable resemblance. Compared to 1000 simulated LCDM  maps, we find  none of them showing such a strong correlation with the foreground map over both large and small angular scales.  In particular, the quadrupole, octopole, and ℓ = 4 and ℓ = 5 modes correlate with the foreground map to a high significance.  The explanation of the largely non-gaussian CMB Cold Spot feature with this model will be particularly discussed. Also I will show new evidence and other possible impacts on our current cosmological scenario.

 

Zoom link: https://univ-amu-fr.zoom.us/j/86077386459?pwd=HO7wadtmGymF5tO9NjcZJLu3Ur56ja.1