A polarized synchrotron template for CMBP experiments after WMAP data

Abstract

We build template maps for the polarized Galactic--synchrotron emission on large angular scales (FWHM =~7${}^{\circ }$), in the 20-90 GHz microwave range, by using WMAP data. The method, presented in a recent work, requires a synchrotron total intensity survey and the {\it polarization horizon} to model the polarized intensity and a starlight polarization map to model polarization angles. The basic template is obtained directly at 23 GHz with about 94% sky--coverage by using the synchrotron map released by the WMAP team. Extrapolations to 32, 60 and 90 GHz are performed by computing a synchrotron spectral index map, which strongly reduces previous uncertainties in passing from low (1.4 GHz) to microwave frequencies. Differing from low frequency data, none of our templates presents relevant structures out of the Galactic Plane. Our map at 90 GHz suggests that the synchrotron emission at high Galactic latitudes is low enough to allow a robust detection of the $E$--mode component of the cosmological signal on large--scale, even in models with low--reionization ($\tau =0.05$). Detection of the weaker $B$--mode on the largest scales ($\ell <10$) might be jeopardized unless the value $\tau =0.17$ found by WMAP is confirmed, and $T/S>0.1$. For lower levels of the gravitational--wave background the $B$--mode seems to be accessible only at the $\ell \sim 100$ peak and in selected low--synchrotron emission areas.

13 pages, 14 figures, accepted for pubblications by MNRAS. For a version with full resolution color figures see http://sp0rt.bo.iasf.cnr.it:8080/Docs/Public/papers.php

References in corpus (13)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission
• Wilkinson Microwave Anisotropy Probe (WMAP) First Year Observations: TE Polarization
• Detection of Polarization in the Cosmic Microwave Background using DASI
• Towards a model of full-sky Galactic synchrotron intensity and linear polarisation: a re-analysis of the Parkes data
• The large-scale anomalous microwave emission revisited by WMAP
• Reappraising foreground contamination in the COBE-DMR data
• The power-law behaviours of angular spectra of polarized Galactic synchrotron
• The Sky Polarization Observatory
• Polarization observations in a low synchrotron emission field at 1.4 GHz
• An iterative destriping technique for diffuse background polarization data
• A New approach for a Galactic Synchrotron Polarized Emission Template in the Microwave Range

Cited by in corpus (15)

• DASI Three-Year Cosmic Microwave Background Polarization Results
• The non-Gaussian Cold Spot in WMAP: significance, morphology and foreground contribution
• Realistic Simulations of the Galactic Polarized Foreground: Consequences for 21-cm Reionization Detection Experiments
• Considerations in optimizing CMB polarization experiments to constrain inflationary physics
• A 189 MHz, 2400 square degree polarization survey with the Murchison Widefield Array 32-element prototype
• Limits on the detectability of the CMB B-mode polarization imposed by foregrounds
• High Galactic latitude polarized emission at 1.4 GHz and implications for cosmic microwave background observations
• The Parkes Galactic Meridian Survey (PGMS): observations and CMB polarization foreground analysis
• 1.4 GHz polarimetric observations of the two fields imaged by the DASI experiment
• Polarized Diffuse Emission at 2.3 GHz in a High Galactic Latitude Area
• Deep 1.4-GHz observations of diffuse polarized emission
• Growing Supermassive Black Holes by Chaotic Accretion
• Cosmic Microwave Background Polarization and reionization: constraining models with a double reionization
• The synchrotron foreground and CMB temperature-polarization cross correlation power spectrum from the first year WMAP data
• ForSE+: Simulating non-Gaussian CMB foregrounds at 3 arcminutes in a stochastic way based on a generative adversarial network