Possible signature of distant foreground in the Planck data

Abstract

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, $z_{\rm SN}$, and CMB temperature fluctuations at the SNe locations, $T_{\rm SN}$, which we previously reported for the Wilkinson Microwave Anisotropy Probe data. The Pearson correlation coefficient for the Planck data is $r=+0.38\pm 0.08$ which indicates that the correlation is statistically significant (the signal is about $5\sigma$ above the noise level). The correlation becomes even stronger for the type Ia subsample of SNe, $r_{\rm Ia}=+0.45\pm 0.09$, whereas for the rest of the SNe it is vanishing. By checking the slopes of the regression lines $T_{\rm SN} / z_{\rm SN}$ 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.