Microwave Emission at High Galactic Latitudes in the Four-Year DMR Sky Maps

We use the COBE Differential Microwave Radiometers (DMR) 4-year sky maps to model Galactic microwave emission at high latitudes (|b| > 20 deg). Cross-correlation of the DMR maps with Galactic template maps detects fluctuations in the high-latitude microwave sky brightness with the angular variation of the DIRBE far-infrared dust maps and a frequency dependence consistent with a superposition of dust and free-free emission. We find no significant correlations between the DMR maps and various synchrotron templates. On the largest angular scales (e. g. , quadrupole), Galactic emission is comparable in amplitude to the anisotropy in the cosmic microwave background (CMB). The CMB quadrupole amplitude, after correction for Galactic emission, has amplitude Qₑ₌ₒ = 10. 7 uK with random uncertainty 3. 6 uK and systematic uncertainty 7. 1 uK from uncertainty in our knowledge of Galactic microwave emission.