Observations of Anomalous Microwave Emission from HII regions

Abstract

In this brief review, I give a summary of the observations of Anomalous Microwave Emission (AME) from HII regions. AME has been detected in, or in the vicinity of, HII regions. Given the difficulties in measuring accurate SEDs over a wide range of frequencies and in complex environments, many of these detections require more data to confirm them as emitting significant AME. The contribution from optically thick free-free emission from UCHII regions may be also be significant in some cases. The AME emissivity, defined as the ratio of the AME brightness to the 100 micron brightness, is comparable to the value observed in high-latitude diffuse cirrus in some regions, but is significantly lower in others. However, this value is dependent on the dust temperature. More data, both at high frequencies (>5 GHz) and high resolution (~1 arcmin or better) is required to disentangle the emission processes in such complex regions.

Published in Advances in Astronomy. Final manuscript can be downloaded from http://www.hindawi.com/journals/aa/2013/162478/

References in corpus (5)

• Centimeter-wave continuum radiation from the rho Ophiuchi molecular cloud
• A multi-wavelength investigation of RCW175: an HII region harboring spinning dust emission
• CBI limits on 31 GHz excess emission in southern HII regions
• AMI limits on 15 GHz excess emission in northern HII regions
• An upper limit on anomalous dust emission at 31 GHz in the diffuse cloud [LPH96]201.663+1.643

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• Constraining the Anomalous Microwave Emission Mechanism in the S140 Star Forming Region with Spectroscopic Observations Between 4 and 8 GHz at the Green Bank Telescope
• Spinning Nanoparticles Impacted by C-shock: Implications for Radio-millimeter Emission from Star-forming Regions