Spectrum of AME-G160.26−18.62 in the Perseus molecular cloud after subtracting the best-fit free-free, CMB and thermal dust components. A theoretical spinning dust model, consisting of two components is shown as the black solid line; the magenta dot-dashed line is for high density molecular gas and the green dotted line is for low density atomic gas, which is a very small contribution in this case (see Sect. 6).