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Title: An improved upper limit to the CMB circular polarization at large angular scales

Circular polarization of the Cosmic Microwave Background (CMB) offers the possibility of detecting rotations of the universe and magnetic fields in the primeval universe or in distant clusters of galaxies. We used the Milano Polarimeter (MIPOL) installed at the Testa Grigia Observatory, on the italian Alps, to improve the existing upper limits to the CMB circular polarization at large angular scales. We obtain 95% confidence level upper limits to the degree of the CMB circular polarization ranging between 5.0⋅10{sup −4} and 0.7⋅10{sup −4} at angular scales between 8° and 24°, improving by one order of magnitude preexisting upper limits at large angular scales. Our results are still far from the nK region where today expectations place the amplitude of the V Stokes parameter used to characterize circular polarization of the CMB but improve the preexisting limit at similar angular scales. Our observations offered also the opportunity of characterizing the atmospheric emission at 33 GHz at the Testa Grigia Observatory.
Authors:
; ; ; ; ; ; ; ;  [1] ;  [2]
  1. Physics Department, University of Milano Bicocca, Milano, I20126 (Italy)
  2. Physics Department, University of Milano, Milano, I20133 (Italy)
Publication Date:
OSTI Identifier:
22282725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2013; Journal Issue: 08; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; ASTROPHYSICS; COSMOLOGY; GALAXY CLUSTERS; GHZ RANGE; MAGNETIC FIELDS; POLARIMETRY; POLARIZATION; RELICT RADIATION; ROTATION; STOKES PARAMETERS; UNIVERSE