Thermal emission from the amorphous dust: An alternative possibility of
  the origin of the anomalous microwave emission
  Complete studies of the radiative processes of thermal emission from the
amorphous dust from microwave through far infrared wavebands are presented by
taking into account, self-consistently for the first time, the standard
two-level systems (TLS) model of amorphous materials. The observed spectral
energy distributions (SEDs) for the Perseus molecular cloud (MC) and W43 from
microwave through far infrared are fitted with the SEDs calculated with the TLS
model of amorphous silicate. We have found that the model SEDs well reproduce
the observed properties of the anomalous microwave emission (AME). The present
result suggests an alternative interpretation for the AME being carried by the
resonance emission of the TLS of amorphous materials without introducing new
species. Simultaneous fitting of the intensity and polarization SEDs for the
Perseus MC and W43 are also performed. The amorphous model reproduces the
overall observed feature of the intensity and polarization SEDs of the Perseus
MC and W43. However, the model's predicted polarization fraction of the AME is
slightly higher than the QUIJOTE upper limits in several frequency bands. A
possible improvement of our model to resolve this problem is proposed. Our
model predicts that interstellar dust is amorphous materials having very
different physical characteristics compared with terrestrial amorphous
materials.
