Identification of Spinning Dust in Halpha-Correlated Microwave Emission
arXiv:0712.2238 · doi:10.1086/587863
Abstract
CMB experiments commonly use maps of Halpha intensity as a spatial template for Galactic free-free emission, assuming a power law I_nu \propto nu^-0.15 for the spectrum. Any departure from the assumed free-free spectrum could have a detrimental effect on determination of the primary CMB anisotropy. We show that the Halpha-correlated emission spectrum in the diffuse warm ionized medium (WIM) is not the expected free-free spectrum at WMAP frequencies. Instead, there is a broad bump in the spectrum at ~50 GHz which is consistent with emission from spinning dust grains. Spectra from both the full sky and smaller regions of interest are well fit by a superposition of a free-free and WIM Draine & Lazarian (1998) spinning dust model, shifted in frequency. The spinning dust emission is ~5 times weaker than the free-free component at 50 GHz, with the null hypothesis that the Halpha-correlated spectrum is pure free-free, ruled out at >8 sigma in all regions and >100 sigma for the full sky fit.
arXiv comment8 pages, 5 figures; submitted to ApJ; LaTeX modified slightly to reveal missing Figure 5
References in corpus (28)
- Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
- HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
- Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission
- Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature Analysis
- Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS
- A Full-Sky H-alpha Template for Microwave Foreground Prediction
- Electric Dipole Radiation from Spinning Dust Grains
- A Robotic Wide-Angle H-Alpha Survey of the Southern Sky
- The Wisconsin H-Alpha Mapper Northern Sky Survey
- Microwave ISM Emission Observed by WMAP
- An Anomalous Component of Galactic Emission
- Microwave Emission at High Galactic Latitudes
- Towards a free-free template for CMB foregrounds
- Extended Anomalous Foreground Emission in the WMAP 3-Year Data
- Magnetic Dipole Microwave Emission from Dust Grains
- Galactic microwave emission at degree angular scales
- Cross-correlation of Tenerife data with Galactic templates - evidence for spinning dust?
- Tentative Detection of Electric Dipole Emission from Rapidly Rotating Dust Grains
- Microwave ISM Emission in the Green Bank Galactic Plane Survey: Evidence for Spinning Dust
- The Quest for Microwave Foreground X
- Galactic emission at 19 GHz
- A New Spin on Galactic Dust
- Radio Emitting Dust in the Free-Electron Layer of Spiral Galaxies: Testing the Disk/Halo Interface
- 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
- Galactic contamination in the QMAP experiment
- Evidence for Inverted Spectrum 20 GHz Emission in the Galactic Plane
Cited by in corpus (25)
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission
- Extended Anomalous Foreground Emission in the WMAP 3-Year Data
- The Galactic Center GeV Excess from a Series of Leptonic Cosmic-Ray Outbursts
- Submillimeter to centimeter excess emission from the Magellanic Clouds. II. On the nature of the excess
- Spinning dust emission: the effect of rotation around a non-principal axis
- Planck 2015 results. XXV. Diffuse low-frequency Galactic foregrounds
- Planck Intermediate Results. IX. Detection of the Galactic haze with Planck
- Observation of the Far-ultraviolet Continuum Background with SPEAR/FIMS
- Parity Asymmetry in the CMBR Temperature Power Spectrum
- Constraining Spinning Dust Parameters with the WMAP Five-Year Data
- H-alpha and Free-Free Emission from the WIM
- A Last Look at the Microwave Haze/Bubbles with WMAP
- On the origins of the diffuse H-alpha emission: Ionized gas or dust-scattered H-alpha halos?
- Bayesian component separation and CMB estimation for the 5-year WMAP temperature data
- The Fermi Gamma-Ray Haze from Dark Matter Annihilations and Anisotropic Diffusion
- Foreground Analysis Using Cross-Correlations of External Templates on the 7-year WMAP data
- Comparison of the Diffuse Halpha and FUV Continuum Backgrounds: On the Origins of the Diffuse Halpha Background
- Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt System
- The C-Band All-Sky Survey (C-BASS): Template Fitting of Diffuse Galactic Microwave Emission in the Northern Sky
- New insights into foreground analysis of the WMAP five-year data using FASTICA
- Analysis of WMAP 7-year Temperature Data: Astrophysics of the Galactic Haze
- Effect of Foregrounds on the CMBR Multipole Alignment
- Cosmic ray backgrounds for dark matter indirect detection
- Evidence for anomalous dust-correlated emission at 8 GHz
- The character of the warm ionised medium