Temperature and polarization angular power spectra of Galactic dust radiation at 353 GHz as measured by Archeops

Abstract

We present the first measurement of temperature and polarization angular power spectra of the diffuse emission of Galactic dust at 353 GHz as seen by Archeops on 20% of the sky. The temperature angular power spectrum is compatible with that provided by the extrapolation to 353 GHz of IRAS and DIRBE maps using Finkbeiner et al. (1999, ApJ, 524, 867) model number 8. For Galactic latitudes |b| ≥ 5 deg we report a 4 sigma detection of large scale (3 ≤ ℓ ≤ 8) temperature-polarization cross-correlation (ℓ + 1)CℓTE/2π = 76 ± 21 μKRJ2 and set upper limits to the E and B mode polarization at 11 μKRJ2. For Galactic latitudes |b| ≥ 10 deg, on the same angular scales, we report a 2 sigma detection of temperature-polarization cross-correlation (ℓ + 1)CℓTE/2π = 24 ± 13 μKRJ2. These results are then extrapolated to 100 GHz to estimate the contamination in CMB measurements by polarized diffuse Galactic dust emission. The TE signal is then 1.7 ± 0.5 and 0.5 ± 0.3 μKCMB2 for |b| ≥ 5 and 10 deg respectively. The upper limit on E and B mode polarization becomes 0.2 μKCMB2 (2σ). If the physical properties of dust radiation on the fraction of the sky observed by Archeops are representative of the whole sky, and if the actual level of E and B mode polarization is close to this upper limit, then dust polarized radiation will be a major foreground for determining the polarization power spectra of the CMB at high frequencies above 100 GHz. © ESO 2005.