Power spectrum of the polarized diffuse Galactic radio emission
C. Baccigalupi, C. Burigana, F. Perrotta, G. De Zotti, L. La Porta, D. Maino, M. Maris, R. Paladini;
AaA, 2001, 372, 8
ABSTRACT:We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming
experiments aimed at detecting the polarized component of Cosmic Microwave
Background (CMB) anisotropies.
Regions were identified for which independent
data consistently indicate that Faraday depolarization may be small.
The
power spectrum of the polarized emission, in terms of antenna temperature,
was found to be described by CPell =~ (1.2+/- 0.8)
10-9* (l 450)1.8+/-0.3* (nu / 2.4 GHz)-5.8
K2, from arcminute to degree scales.
Data on larger angular scales
(l<= 100) indicate a steeper slope ~ l-3.
We conclude that
polarized Galactic emission is unlikely to be a serious limitation to CMB
polarization measurements at the highest frequencies of the MAP and Planck-LFI
instruments, at least for l>= 50 and standard cosmological models.
The weak
correlation between polarization and total power and the low polarization degree
of radio emission close to the Galactic plane is interpreted as due to
large contributions to the observed intensity from unpolarized sources,
primarily strong Hii regions, concentrated on the Galactic plane.
Thus
estimates of the power spectrum of total intensity at low Galactic latitudes are
not representative of the spatial distribution of Galactic emission far
from the plane.
Both total power and polarized emissions show highly
significant deviations from a Gaussian distribution.
KEYWORDS: polarization, ism: structure, galaxy: general, cosmology: cosmic microwave background, radio continuum: ism
PERSOKEY:polarisation, RADIO CONTINUUM, component separation, ,
CODE: baccigalupi2001