scholarly journals The polarimetric multi-frequency radio sources properties

2016 ◽  
Vol 25 (11) ◽  
pp. 1640005 ◽  
Author(s):  
Vincenzo Galluzzi ◽  
Marcella Massardi
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
State Of The Art ◽  
The State ◽  
Radio Sources ◽  
Microwave Background ◽  
Complete Sample ◽  
Angular Power Spectrum ◽  
Extragalactic Radio Sources ◽  
Compact Array

The polarization properties of extragalactic radio sources at frequencies higher than [Formula: see text]GHz are still poorly constrained. However, their characterization would provide invaluable information about the physics of the emission processes and is crucial to estimate their contamination as foregrounds of the polarized Cosmic Microwave Background (CMB) angular power spectrum on scales [Formula: see text]arcmin. In this contribution, after summarizing the state-of-the-art of polarimetric observations in the millimetric wavelength bands, we present our observations of a complete sample of 53 sources with [Formula: see text]mJy carried out with the Australia Telescope Compact Array (ACTA) between [Formula: see text] and [Formula: see text]GHz. The analysis clearly shows that polarization properties cannot be simply inferred from total intensity ones, as the spectral behaviors of the two signals are typically different.

A Measurement by BOOMERANG of Multiple Peaks in the Angular Power Spectrum of the Cosmic Microwave Background

2002 ◽  
Vol 571 (2) ◽  
pp. 604-614 ◽  
Author(s):  
C. B. Netterfield ◽  
P. A. R. Ade ◽  
J. J. Bock ◽  
J. R. Bond ◽  
J. Borrill ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Microwave Background ◽  
Angular Power Spectrum ◽  
Multiple Peaks

A Measurement of the Angular Power Spectrum of the Cosmic Microwave Background from [CLC][ITAL]l[/ITAL][/CLC] = 100 to 400

1999 ◽  
Vol 524 (1) ◽  
pp. L1-L4 ◽  
Author(s):  
A. D. Miller ◽  
R. Caldwell ◽  
M. J. Devlin ◽  
W. B. Dorwart ◽  
T. Herbig ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Microwave Background ◽  
Angular Power Spectrum

scholarly journals Cosmic Strings and Their Induced Non-Gaussianities in the Cosmic Microwave Background

2010 ◽  
Vol 2010 ◽  
pp. 1-28 ◽  
Author(s):  
Christophe Ringeval
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Cosmic Strings ◽  
Point Function ◽  
Microwave Background ◽  
Angular Power Spectrum ◽  
Gravitational Perturbations ◽  
The One ◽  
Non Gaussian

Motivated by the fact that cosmological perturbations of inflationary quantum origin were born Gaussian, the search for non-Gaussianities in the cosmic microwave background (CMB) anisotropies is considered as the privileged probe of nonlinear physics in the early universe. Cosmic strings are active sources of gravitational perturbations and incessantly produce non-Gaussian distortions in the CMB. Even if, on the currently observed angular scales, they can only contribute a small fraction of the CMB angular power spectrum, cosmic strings could actually be the main source of its non-Gaussianities. In this paper, after having reviewed the basic cosmological properties of a string network, we present the signatures Nambu-Goto cosmic strings would induce in various observables ranging from the one-point function of the temperature anisotropies to the bispectrum and trispectrum. It is shown that string imprints are significantly different than those expected from the primordial type of non-Gaussianity and could therefore be easily distinguished.

Polarization of extragalactic radio sources: CMB foregrounds and telescope calibration issues

2016 ◽  
Vol 25 (11) ◽  
pp. 1640009 ◽  
Author(s):  
Marcella Massardi ◽  
Vincenzo Galluzzi ◽  
Rosita Paladino ◽  
Carlo Burigana
Keyword(s):  
Cosmic Microwave Background ◽  
Radio Source ◽  
High Redshift ◽  
The Other ◽  
Radio Sources ◽  
Polarization Rotation ◽  
Microwave Background ◽  
Extragalactic Radio Sources ◽  
Systematic Effects ◽  
The One

Radio source observations play important roles in polarimetric cosmological studies. On the one hand, they constitute the main foregrounds for cosmic microwave background (CMB) radiation on scales smaller than 30 arcmin up to 100 GHz, on the other they can be used as targets for validation of products of polarimetric experiments dedicated to cosmology. Furthermore, extragalactic high-redshift sources have been used for cosmic polarization rotation (CPR) investigation. In this paper, we will discuss the support to cosmological studies from ground-based polarimetric observations in the radio and millimetric wavelength bands. Most of the limits to accuracy improvements arise from systematic effects and low calibration quality. We will discuss some details of interferometric calibration procedures and show some of the perspectives that the Atacama large millimeter array (ALMA) could offer for CPR studies.

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