Spinning Dust Emission from Wobbling Grains: Important Physical Effects and Implications

We review the major progress on the modeling of electric dipole emission from rapidly spinning tiny dust grains, including polycyclic aromatic hydrocarbons (PAHs). We begin by summarizing the original model of spinning dust proposed by Draine and Lazarian and recent theoretical results improving the Draine and Lazarian model. The paper is focused on important physical effects that were disregarded in earlier studies for the sake of simplicity and recently accounted for by us, including grain wobbling due to internal relaxation, impulsive excitation by single-ion collisions, the triaxiality of grain shape, charge fluctuations, and the turbulent nature of astrophysical environments. Implications of the spinning dust for constraining the physical properties of ultrasmall dust grains and environmental conditions are discussed. We discuss the alignment of tiny dust grains and the possibility of polarized spinning dust emission. Suggestions for constraining the alignment of tiny grains and polarization of spinning dust are also discussed.