VSA Observations of the Anomalous Microwave Emission in the Perseus Region

TL;DR

This study uses VSA observations at 33 GHz to analyze the dust feature G159.6--18.5 in Perseus, revealing five components with anomalous microwave emission likely from spinning dust grains, enhancing understanding of such emissions.

Contribution

First detailed VSA analysis of G159.6--18.5's components, confirming their anomalous emission consistent with spinning dust models.

Findings

All five components show excess emission at 33 GHz.

Components are highly correlated with far-infrared emission.

Emission is consistent with electric dipole radiation from small dust grains.

Abstract

The dust feature G159.6--18.5 in the Perseus region has previously been observed with the COSMOSOMAS experiment \citep{Watson:05} on angular scales of $\approx$ 1$^{\circ}$, and was found to exhibit anomalous microwave emission. We present new observations of this dust feature, performed with the Very Small Array (VSA) at 33 GHz, to help increase the understanding of the nature of this anomalous emission. On the angular scales observed with the VSA ($\approx$ 10 -- 40$^{\prime}$), G159.6--18.5 consists of five distinct components, each of which have been individually analysed. All five of these components are found to exhibit an excess of emission at 33 GHz, and are found to be highly correlated with far-infrared emission. We provide evidence that each of these compact components have anomalous emission that is consistent with electric dipole emission from very small, rapidly rotating dust grains. These components contribute $\approx$ 10 % to the flux density of the diffuse extended emission detected by COSMOSOMAS, and are found to have a similar radio emissivity.