Astrophysics Seminar: Yue Hu, University of Wisconsin-Madison


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Predictions of cosmic microwave background foreground dust polarization using velocity gradients

Yue Hu
Graduate Student, University of Wisconsin-Madison

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 polarized radiation arising from dust aligned by interstellar magnetic fields. To trace magnetic fields, we use the Velocity Gradient Technique (VGT), which employs modern understanding of the nature of magnetohydrodynamic turbulent motions. We apply the VGT to the high-resolution neutral hydrogen data from the GALFA-H I survey to predict the polarization of dust. We report that the predicted directions of dust polarization provide good correspondence with those reported by Planck 353 GHz. Using our maps of predicted polarization, we calculate the ratio of the E- and B-modes, and show that BB/EE ~ 0.53 ± 0.10, which is similar to the result from Planck polarization.

Hosted by Prof. Lan Quynh Nguyen

All interested persons are invited to attend remotely—email for information.

Originally published at

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