Observation number correlation in WMAP data

Understand

A remarkable similarity between the large-scale non-Gaussian pattern of cosmic microwave background (CMB) temperatures obtained by Wilkinson Microwave Anisotropy Probe (WMAP) mission and the distribution feature of observation numbers is noted.

• Motivated from such a similarity, in this work we check the WMAP data for the correlation between pixel temperature t and observation number N.
• Systematic effect of imbalance differential observation and significant t-N correlation in magnitude, distribution non-Gaussianity and north-south asymmetry are found.
• Our results indicate that, for precision cosmology study based on WMAP observations, the observation effect on released WMAP temperature maps has to be further carefully studied.