A look at possible microwave dust emission via AKARI infrared all-sky surveys

Abstract

The anomalous microwave emission (AME) still lacks a conclusive explanation. This excess of emission, roughly between 10 and 50 GHz, correlates spatially with interstellar dust, prompting a "spinning dust" hypothesis: electric dipole emission by rapidly rotating, small dust grains. The typical peak frequency range of the AME profile implicates grains on the order of ~1 nm, suggesting polycyclic aromatic hydrocarbon molecules (PAHs). We compare AKARI/Infrared Camera (IRC), with its thorough PAH-band coverage, to AME intensity estimates from the Planck Collaboration, in the λ Orionis region. We look also at infrared dust emission from other mid IR and far-IR bands. The results and discussion contained here apply to an angular scale of approximately 1°. In general, our results support an AME-from-dust hypothesis. In λ Orionis, we find that certainly dust mass correlates with AME, and that PAH-related emission in the AKARI/IRC 9 μm band may correlate slightly more strongly.

4 pages, 3 figures, to appear in proceedings of AKARI Conference 2017, "The Cosmic Wheel and the Legacy of the AKARI Archive: From Galaxies and Stars to Planets and Life", comments welcome