Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure

Understand

21 cm cosmology is a promising new probe of the evolution of visible matter in our universe, especially during the poorly-constrained Cosmic Dawn and Epoch of Reionization.

• However, in order to separate the 21 cm signal from bright astrophysical foregrounds, we need an exquisite understanding of our telescopes so as to avoid adding spectral structure to spectrally-smooth foregrounds.
• One powerful calibration method relies on repeated simultaneous measurements of the same interferometric baseline to solve for the sky signal and for instrumental parameters simultaneously.
• However, certain degrees of freedom are not constrained by asserting internal consistency between redundant measurements.