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

TL;DR

This study investigates the connection between microwave anomalous emission and interstellar dust, especially PAHs, using AKARI infrared data and Planck AME estimates, supporting the dust-origin hypothesis of AME.

Contribution

It provides a comparative analysis of AKARI infrared observations with Planck AME data, highlighting the potential role of PAHs in microwave dust emission.

Findings

Dust mass correlates with AME intensity.

PAH-related 9 μm emission may have a stronger correlation.

Results support the dust-origin hypothesis for AME.

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 {\lambda} 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{\deg}. In general, our results support an AME-from-dust hypothesis. In {\lambda} Orionis, we find that certainly dust mass correlates with AME, and that PAH-related emission in the AKARI/IRC 9 {\mu}m band may correlate slightly more strongly.