  We employ the one-dimensional Fourier representation (1DFR) to analyze the
3-year WMAP de-biased internal linear combination (DILC) map and its possible
contamination by galactic foregrounds. The 1DFR is a representation of the
spherical harmonic coefficients for each l mode using an inverse Fourier
transform into one-dimensional curves. Based on the a priori assumption that
the CMB signal should be statistically independent of, and consequently have no
significant correlation with, any foregrounds, we cross-correlate the 1DFR
curves of 2 <= l <= 10 modes, which are claimed by the WMAP team to be free of
contamination and suitable for whole sky analysis. We find that 8 out of the 9
modes are negatively cross correlated with the foreground maps, an event which
has a probability of only 9/512 ~ 0.0176 for uncorrelated signals. Furthermore,
the local extrema of the 1DFR curves between the DILC and those of the
foregrounds for l=2 and 6 are correlated with significance level below 0.04. We
also discuss the minimum variance optimization method and use the properties of
the measured cross-correlation to estimate the possible level of contamination
present in the DILC map.
