Possible signature of distant foreground in the Planck data

By using the Planck map of the cosmic microwave background (CMB) radiation, we have checked and confirmed the existence of a correlation between supernova (SN) redshifts, z SN, and CMB temperature fluctuations at the SNe locations, T SN, which we previously reported for the Wilkinson Microwave Anisotropy Probe data. The Pearson correlation coefficient for the Planck data is r = +0.38 ± 0.08, which indicates that the correlation is statistically significant (the signal is about 5σ above the noise level). The correlation becomes even stronger for the Type Ia subsample of SNe, r Ia = +0.45 ± 0.09, whereas for the rest of the SNe it is vanishing. By checking the slopes of the regression lines T SN/z SN for Planck's different frequency bands, we have also excluded the possibility of this anomaly being caused by the Sunyaev–Zeldovich effect. The remaining possibility is some, unaccounted for, contribution to the CMB from distant (z > 0.3) foreground through either the integrated Sachs–Wolfe effect or thermal emission from intergalactic matter.