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Title: Planck Dust Polarization Power Spectra Are Consistent with Strongly Supersonic Turbulence
The polarization of the cosmic microwave background is rich in information but obscured by foreground emission from the Milky Way's interstellar medium (ISM). To uncover relationships between the underlying turbulent ISM and the foreground power spectra, we simulated a suite of driven, magnetized, turbulent models of the ISM, varying the fluid properties via the sonic Mach number and magnetic (Alfvén) Mach number, . We measure the power spectra of density (ρ), velocity (v), magnetic field (H), total projected intensity (T), parity-even polarization (E), and parity-odd polarization (B). We find that the slopes of all six quantities increase with sonic Mach number. Most increase with Alfven Mach number, while the magnetic field spectrum steepens with Alfven Mach number. By comparing spectral slopes of E and B to those measured by Planck, we infer typical values of sonic and Alfven Mach numbers for the ISM. As the fluid velocity increases and the sonic Mach number exceed 4, the ratio of BB power to EE power increases to approach a constant value near the Planck-observed value of ~0.5, regardless of the magnetic field strength. We also examine correlation coefficients between projected quantities, and find that the TE cross-correlation is ~0.3, in agreement with Planck, for appropriate combinations of Mach numbers. Finally, we consider parity-violating correlations..  more » « less
Award ID(s):
2009870
PAR ID:
10557337
Author(s) / Creator(s):
; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
972
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
26
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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