AMI Observations of the Anomalous Microwave Emission in the Perseus Molecular Cloud

TL;DR

This study presents high-resolution microwave observations of the Perseus molecular cloud's anomalous emission, revealing a correlation with infrared data that supports spinning dust grains as the emission source.

Contribution

First high-resolution microwave observations of G159.6-18.5, combined with infrared data, to investigate the origin of anomalous microwave emission in Perseus.

Findings

Microwave-infrared correlation increases at shorter infrared wavelengths.

Correlation peaks at 24 μm, indicating small, stochastically heated dust grains.

Supports spinning dust grains as the source of anomalous microwave emission.

Abstract

We present observations of the known anomalous microwave emission region, G159.6-18.5, in the Perseus molecular cloud at 16 GHz performed with the Arcminute Microkelvin Imager Small Array. These are the highest angular resolution observations of G159.6-18.5 at microwave wavelengths. By combining these microwave data with infrared observations between 5.8 and 160 \mu m from the Spitzer Space Telescope, we investigate the existence of a microwave - infrared correlation on angular scales of ~2 arcmin. We find that the overall correlation appears to increase towards shorter infrared wavelengths, which is consistent with the microwave emission being produced by electric dipole radiation from small, spinning dust grains. We also find that the microwave - infrared correlation peaks at 24 \mu m (6.7\sigma), suggesting that the microwave emission is originating from a population of stochastically heated small interstellar dust grains rather than polycyclic aromatic hydrocarbons.