paper / charlesbennett / Sep 3
Improved foreground cleaning methods and minimal sky masking (1%) significantly reduce the statistical significance of two out of five commonly studied Cosmic Microwave Background (CMB) anomalies, specifically the low real-space correlation function and local-variance asymmetry. While other anomalies like low northern variance, parity asymmetry, and quadrupole-octopole alignment retain their significance even with full-sky analyses, the findings suggest that some previously observed CMB anomalies may be artifacts of processing choices rather than indicators of new physics beyond the \textLambda CDM model. Further research on alternative physical models must explain multiple CMB anomalies or provide better descriptions of other observational data to be considered convincingly superior to the standard cosmological model.
cosmic-microwave-backgroundcmb-anomalieslow-multipole-anisotropyforeground-cleaningcosmologyastrophysics
“The statistical significance of the low real-space correlation function anomaly is reduced when using a minimal galactic mask.”
paper / charlesbennett / Sep 3
A novel analysis of WMAP and Planck CMB data, employing a template-based foreground cleaning approach, has enabled a nearly full-sky recovery of temperature anisotropy at multipoles ℓ<30. This new methodology confirms persistent anomalies such as a low quadrupole power and an overall deficit in power compared to the ΛCDM model, while also providing refined cosmological parameter constraints consistent with previous Planck results, exemplified by a precise Hubble constant measurement.
cmb-anisotropycosmologyplanck-missionwmap-dataangular-power-spectra
“The CMB temperature power spectrum at large angular scales (multipoles ℓ<30) has been measured using a template-based foreground cleaning method on WMAP and Planck maps.”
paper / charlesbennett / Sep 3
The presented research details the creation of new cosmic microwave background (CMB) temperature maps with significantly reduced foreground contamination and nearly full-sky coverage (only 1% masked pixels). These maps leverage a template-based cleaning method applied to WMAP and Planck data, foregoing spectral index constraints and inpainting. This advancement is crucial for low multipole (l < 30) studies, where foreground contamination typically limits analysis.
cosmic-microwave-backgroundcmb-anisotropyforeground-cleaningastrophysicscosmologywmap-dataplanck-data
“Foreground contamination is a major limitation in cosmic microwave background (CMB) studies.”
paper / charlesbennett / Aug 28
This paper demonstrates the utility of conductively-loaded, polyimide aerogel filters for astronomical and planetary science applications. These filters, designed for far-infrared, sub-millimeter, and microwave regimes, exhibit mechanical stability at cryogenic temperatures and perform within the requirements of current experiments. Their estimated integrated infrared emissivity provides crucial data for future instrument integration.
astrophysics-instrumentationmaterials-scienceaerogelsinfrared-filterscryogenic-testingplanetary-sciencecosmology
“Diamond-loaded polyimide aerogel filters are suitable for cryogenic astronomical and planetary science instruments.”
paper / charlesbennett / Jan 21
The Cosmology Large Angular Scale Surveyor (CLASS) 90 GHz data successfully measured large-scale CMB E-mode polarization with high sensitivity. The analysis addressed systematic errors and power recovery challenges through a novel pixel-space transfer matrix. This enabled an unbiased correction for time-domain filtering, allowing for the first ground-based detection of cosmic reionization and measurement of its optical depth.
cosmic-microwave-backgrounde-mode-polarizationreionizationcosmology-instrumentsastrophysics-measurementsdata-analysis-methods
“The CLASS experiment achieved a polarization sensitivity of 78 µK arcmin at 90 GHz, comparable to Planck.”