Anomalous microwave emission ( AME ) is a category of Galactic signals that can not be explained by synchrotron radiation , thermal dust emission , or optically thin free-free radiation . Spinning dust is one variety of AME that could be partially polarized and therefore relevant for ongoing and future cosmic microwave background polarization studies . The Planck satellite mission identified candidate AME regions in approximately 1 ^ { \circ } patches that were found to have spectra generally consistent with spinning dust grain models . The spectra for one of these regions , G107.2+5.2 , was also consistent with optically thick free-free emission because of a lack of measurements between 2 and 20 GHz . Follow-up observations were needed . Therefore , we used the C-band receiver ( 4 to 8 GHz ) and the VEGAS spectrometer at the Green Bank Telescope to constrain the AME mechanism . For the study described in this paper , we produced three band averaged maps at 4.575 , 5.625 , and 6.125 GHz and used aperture photometry to measure the spectral flux density in the region relative to the background . We found if the spinning dust description is correct , then the spinning dust signal peaks at 30.9 \pm 1.4 GHz , and it explains the excess emission . The morphology and spectrum together suggest the spinning dust grains are concentrated near S140 , which is a star forming region inside our chosen photometry aperture . If the AME is sourced by optically thick free-free radiation , then the region would have to contain HII with an emission measure of 5.27 ^ { +2.5 } _ { -1.5 } \times 10 ^ { 8 } { cm ^ { -6 } pc } and a physical extent of 1.01 ^ { +0.21 } _ { -0.20 } \times 10 ^ { -2 } pc . This result suggests the HII would have to be ultra or hyper compact to remain an AME candidate .