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Title: Constraint on the polarization of electric dipole emission from spinning dust

Planck results have revealed that the electric dipole emission from polycyclic aromatic hydrocarbons (PAHs) is the most reliable explanation for the anomalous microwave emission that interferes with cosmic microwave background (CMB) radiation experiments. The emerging question is to what extent this emission component contaminates the polarized CMB radiation. We present constraints on polarized dust emission for the model of grain-size distribution and grain alignment that best fits the observed extinction and polarization curves. Two stars with a prominent polarization feature at λ = 2175 Å—HD 197770 and HD 147933-4—are chosen for our study. For HD 197770, we find that the model with aligned silicate grains plus weakly aligned PAHs can successfully reproduce the 2175 Å polarization feature; in contrast, for HD 147933-4, we find that the alignment of only silicate grains can account for that feature. The alignment function of PAHs for the best-fit model to the HD 197770 data is used to constrain polarized spinning dust emission. We find that the degree of polarization of spinning dust emission is about 1.6% at frequency ν ≈ 3 GHz and declines to below 0.9% for ν > 20 GHz. We also predict the degree of polarization of thermal dust emission atmore » 353 GHz to be P {sub em} ≈ 11% and 14% for the lines of sight to the HD 197770 and HD 147933-4 stars, respectively.« less
Authors:
;  [1] ;  [2]
  1. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)
  2. Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53705 (United States)
Publication Date:
OSTI Identifier:
22348429
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BACKGROUND RADIATION; DISTRIBUTION; DUSTS; ELECTRIC DIPOLES; EMISSION; GRAIN SIZE; LIMITING VALUES; POLARIZATION; POLYCYCLIC AROMATIC HYDROCARBONS; RELICT RADIATION; STARS