English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Spectral measurements of the 21 cm monopole background have the promise ofrevealing the bulk energetic properties and ionization state of our universefrom z ~ 6-30. Synchrotron foregrounds are orders of magnitude larger than thecosmological signal, and are the principal challenge faced by theseexperiments. While synchrotron radiation is thought to be spectrally smooth anddescribed by relatively few degrees of freedom, the instrumental response tobright foregrounds may be much more complex. To deal with such complexities, wedevelop an approach that discovers contaminated spectral modes using spatialfluctuations of the measured data. This approach exploits the fact thatforegrounds vary across the sky while the signal does not. The discovered modesare projected out of each line-of-sight of a data cube. An angular weightingthen optimizes the cosmological signal amplitude estimate by giving preferenceto lower-noise regions. Using this method, we show that it is essential for thepassband to be stable to at least ~10^{-4}. In contrast, the constraints on thespectral smoothness of the absolute calibration are mainly aesthetic if one isable to take advantage of spatial information. To the extent it is understood,controlling polarization to intensity leakage at the ~10^{-2} level will alsobe essential to rejecting Faraday rotation of the polarized synchrotronemission.

Erasing the variable: Empirical foreground discovery for global 21 cm spectrum experiments