Search for: All records

Abstract We present evidence for scale-independent misalignment of interstellar dust filaments and magnetic fields. We estimate the misalignment by comparing millimeter-wave dust-polarization measurements from Planck with filamentary structures identified in neutral-hydrogen (Hi) measurements from Hi4PI. We find that the misalignment angle displays a scale independence (harmonic coherence) for features larger than the Hi4PI beamwidth (16.′2). We additionally find a spatial coherence on angular scales of $\mathit{}(1°)$. We present several misalignment estimators formed from the auto- and cross-spectra of dust-polarization and Hi-based maps, and we also introduce a map-space estimator. Applied to large regions of the high-Galactic-latitude sky, we find a global misalignment angle of ∼2°, which is robust to a variety of masking choices. By dividing the sky into small regions, we show that the misalignment angle correlates with the parity-violatingTBcross-spectrum measured in the Planck dust maps. The misalignment paradigm also predicts a dustEBsignal, which is of relevance in the search for cosmic birefringence but as yet undetected; the measurements ofEBare noisier than those ofTB, and our correlations ofEBwith misalignment angle are found to be weaker and less robust to masking choices. We also introduce an Hi-based dust-polarization template constructed from the Hessian matrix of the Hiintensity, which is found to correlate more strongly than previous templates with Planck dustBmodes. 

Observations of the Cosmic Microwave Background rely on cryogenic instrumentation with cold detectors, readout, and optics providing the low noise performance and instrumental stability required to make more sensitive measurements. It is therefore critical to optimize all aspects of the cryogenic design to achieve the necessary performance, with low temperature components and acceptable system cooling requirements. In particular, we will focus on our use of thermal filters and cold optics, which reduce the thermal load passed along to the cryogenic stages. To test their performance, we have made a series of in situ measurements while integrating the third receiver for the BICEP Array telescope. In addition to characterizing the behavior of this receiver, these measurements continue to refine the models that are being used to inform design choices being made for future instruments.