Predictions of Cosmic Microwave Background Foregrounds Dust Polarization Using Velocity Gradients. (arXiv:1910.05637v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Hu_Y/0/1/0/all/0/1">Yue Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuen_K/0/1/0/all/0/1">Ka Ho Yuen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazarian_A/0/1/0/all/0/1">Alex Lazarian</a>
The observations of fluctuations in the cosmic microwave background provide
information about primordial inhomogeneities in the universe. However, the
B-mode polarization of the inflationary gravitational wave is contaminated by
the Galactic foreground polarization arising from complicated interstellar
magnetic fields. Based on the modern theory of magneto-hydrodynamics
turbulence, the Velocity Gradient Technique (VGT) is developed as a new tool
for studying magnetic fields and the interstellar medium. In this paper, we
extend the VGT technique by using the Principal Component Analysis (PCA) and
use the technique to characterizing the Galactic foreground polarization from
aligned dust. We apply our technique to all high-resolution neutral hydrogen
data from the GALFA-HI survey and find the predicted polarization agrees with
Planck 353GHz polarized dust emission. We show that our results statistically
agree with the Planck polarization in terms of magnetic field tracing. We find
that the variation of dust emission efficiency across the sky is small. We
calculate the angular power spectrum of HI derived polarization maps and show
BB/EE~0.53, which coincides with the result from Plank polarization.
The observations of fluctuations in the cosmic microwave background provide
information about primordial inhomogeneities in the universe. However, the
B-mode polarization of the inflationary gravitational wave is contaminated by
the Galactic foreground polarization arising from complicated interstellar
magnetic fields. Based on the modern theory of magneto-hydrodynamics
turbulence, the Velocity Gradient Technique (VGT) is developed as a new tool
for studying magnetic fields and the interstellar medium. In this paper, we
extend the VGT technique by using the Principal Component Analysis (PCA) and
use the technique to characterizing the Galactic foreground polarization from
aligned dust. We apply our technique to all high-resolution neutral hydrogen
data from the GALFA-HI survey and find the predicted polarization agrees with
Planck 353GHz polarized dust emission. We show that our results statistically
agree with the Planck polarization in terms of magnetic field tracing. We find
that the variation of dust emission efficiency across the sky is small. We
calculate the angular power spectrum of HI derived polarization maps and show
BB/EE~0.53, which coincides with the result from Plank polarization.
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