Haslam Map and WMAP

The Haslam Map measures synchrotron radiation at a radio frequency. From this data, Finkbeiner can infer the brightness of ordinary synchrotron radiation, such as supernovae, across the full microwave spectrum. Finkbeiner compares this level of brightness, or spectrum, with WMAP, which measured microwave emissions at five different frequencies in the higher range. At these frequencies, WMAP shows a higher intensity of synchrotron radiation or a harder spectrum that cannot be explained by the Haslam Map.