A multi-wavelength investigation of RCW175: an HII region harboring
  spinning dust emission
  Using infrared, radio continuum and spectral observations, we performed a
detailed investigation of the HII region RCW175. We determined that RCW175,
which actually consists of two separate HII regions, G29.1-0.7 and G29.0-0.6,
is located at a distance of 3.2+/-0.2 kpc. Based on the observations we infer
that the more compact G29.0-0.6 is less evolved than G29.1-0.7 and was possibly
produced as a result of the expansion of G29.1-0.7 into the surrounding
interstellar medium. We compute a star formation rate for RCW175 of
(12.6+/-1.9)x10^{-5} M_{\sun}/yr, and identified 6 possible young stellar
object candidates within its vicinity. Additionally, we estimate that RCW175
contains a total dust mass of 215+/-53 M_{\sun}.
  RCW175 has previously been identified as a source of anomalous microwave
emission (AME), an excess of emission at cm wavelengths often attributed to
electric dipole radiation from the smallest dust grains. We find that the AME
previously detected in RCW175 is not correlated with the smallest dust grains
(polycyclic aromatic hydrocarbons or small carbonaceous dust grains), but
rather with the exciting radiation field within the region. This is a similar
result to that found in the Perseus molecular cloud, another region which
harbors AME, suggesting that the radiation field may play a pivotal role in the
production of this new Galactic emission mechanism. Finally, we suggest that
these observations may hint at the importance of understanding the role played
by the major gas ions in spinning dust models.
