Anomalous Microwave Emission from the HII region RCW175

Abstract

We present evidence for anomalous microwave emission in the RCW175 \hii region. Motivated by 33 GHz $13\arcmin$ resolution data from the Very Small Array (VSA), we observed RCW175 at 31 GHz with the Cosmic Background Imager (CBI) at a resolution of $4\arcmin$. The region consists of two distinct components, G29.0-0.6 and G29.1-0.7, which are detected at high signal-to-noise ratio. The integrated flux density is $5.97\pm 0.30$ Jy at 31 GHz, in good agreement with the VSA. The 31 GHz flux density is $3.28\pm 0.38$ Jy ($8.6\sigma$) above the expected value from optically thin free-free emission based on lower frequency radio data and thermal dust constrained by IRAS and WMAP data. Conventional emission mechanisms such as optically thick emission from ultracompact \hii regions cannot easily account for this excess. We interpret the excess as evidence for electric dipole emission from small spinning dust grains, which does provide an adequate fit to the data.

5 pages, 2 figures, submmited to ApJ Letters

References in corpus (7)

• WMAP 3yr data with the CCA: anomalous emission and impact of component separation on the CMB power spectrum
• CBI limits on 31 GHz excess emission in southern HII regions
• AMI limits on 15 GHz excess emission in northern HII regions
• COSMOSOMAS Observations of the CMB and Galactic Foregrounds at 11 GHz: Evidence for anomalous microwave emission at high Galactic Latitude
• An upper limit on anomalous dust emission at 31 GHz in the diffuse cloud [LPH96]201.663+1.643
• Constraints on spinning dust towards Galactic targets with the VSA: a tentative detection of excess microwave emission towards 3C396
• A centimetre-wave excess over free-free emission in planetary nebulae

Cited by in corpus (48)

• Planck early results. XX. New light on anomalous microwave emission from spinning dust grains
• A refined model for spinning dust radiation
• Spinning dust emission: the effect of rotation around a non-principal axis
• The State-of-Play of Anomalous Microwave Emission (AME) Research
• The Star Formation in Radio Survey: GBT 33 GHz Observations of Nearby Galaxy Nuclei and Extranuclear Star-Forming Regions
• The Detection of Anomalous Dust Emission in the Nearby Galaxy NGC 6946
• Measurements of the Intensity and Polarization of the Anomalous Microwave Emission in the Perseus molecular complex with QUIJOTE
• QUIJOTE Scientific Results. II. Polarisation Measurements of the Microwave Emission in the Galactic molecular complexes W43 and W47 and supernova remnant W44
• COMAP Early Science: I. Overview
• The JCMT Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud
• VSA Observations of the Anomalous Microwave Emission in the Perseus Region
• Galactic foreground contributions to the WMAP5 maps
• Constraint on the Polarization of Electric Dipole Emission from Spinning Dust
• A multi-wavelength investigation of RCW175: an HII region harboring spinning dust emission
• New constraints on the Polarization of Anomalous Microwave Emission in nearby molecular clouds
• Spitzer characterisation of dust in an anomalous emission region: the Perseus cloud
• Bayesian component separation and CMB estimation for the 5-year WMAP temperature data
• 90GHz and 150GHz observations of the Orion M42 region. A sub-millimeter to radio analysis
• Dust-correlated cm-wavelength continuum emission on translucent clouds ζ Oph and LDN 1780
• Dust-correlated centimetre-wave radiation from the M 78 reflection nebula
• IR-correlated 31 GHz radio emission from Orion East
• Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt System
• Detection of Spectral Variations of Anomalous Microwave Emission with QUIJOTE and C-BASS
• An excess of emission in the dark cloud LDN 1111 with the Arcminute Microkelvin Imager
• Rotational spectroscopy of interstellar PAHs
• New radio observations of anomalous microwave emission in the HII region RCW175
• Detection of Anomalous Microwave Emission in the Pleiades Reflection Nebula with WMAP and the COSMOSOMAS Experiment
• COMAP Early Science: VI. A First Look at the COMAP Galactic Plane Survey
• AMI Observations of the Anomalous Microwave Emission in the Perseus Molecular Cloud
• The C-Band All-Sky Survey (C-BASS): Constraining diffuse Galactic radio emission in the North Celestial Pole region
• A 33 GHz VSA survey of the Galactic plane from 27 to 46 degrees
• Resolved observations at 31 GHz of spinning dust emissivity variations in $\rho$ Oph
• QUIJOTE scientific results -- X. Spatial variations of Anomalous Microwave Emission along the Galactic plane
• Observations of Free-Free and Anomalous Microwave Emission from LDN 1622 with the 100 m Green Bank Telescope
• Modelling the spinning dust emission from LDN 1780
• Anomalous Microwave Emission in HII regions: is it really anomalous? The case of RCW 49
• Where's the Dust?: The Deepening Anomaly of Microwave Emission in NGC 4725 B
• QUIJOTE scientific results -- V. The microwave intensity and polarisation spectra of the Galactic regions W49, W51 and IC443
• The Cosmic Background Imager 2
• Evidence for anomalous dust-correlated emission at 8 GHz
• Observations of Galactic star-forming regions with the Cosmic Background Imager at 31 GHz
• Large Radio Telescopes for Anomalous Microwave Emission Observations
• Observations of Anomalous Microwave Emission from HII regions
• QUIJOTE scientific results -- XVIII. New constraints on the polarization of the Anomalous Microwave Emission in bright Galactic regions: $\rho$\,Ophiuchi, Perseus and W43
• Anomalous Emission from HII regions
• Spinning Nanoparticles Impacted by C-shock: Implications for Radio-millimeter Emission from Star-forming Regions
• A characterization of the diffuse Galactic emissions in the anti-center of the Galaxy
• A characterization of the diffuse Galactic emissions at large angular scales using the Tenerife data