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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A number of experiments are set to measure the 21-cm signal of neutralhydrogen from the Epoch of Reionization (EoR). The common denominator of theseexperiments are the large data sets produced, contaminated by variousinstrumental effects, ionospheric distortions, RFI and strong Galactic andextragalactic foregrounds. In this paper, the first in a series, we present theData Model that will be the basis of the signal analysis for the LOFAR (LowFrequency Array) EoR Key Science Project (LOFAR EoR KSP). Using this data modelwe simulate realistic visibility data sets over a wide frequency band, takingproperly into account all currently known instrumental corruptions (e.g.direction-dependent gains, complex gains, polarization effects, noise, etc). Wethen apply primary calibration errors to the data in a statistical sense,assuming that the calibration errors are random Gaussian variates at a levelconsistent with our current knowledge based on observations with the LOFAR CoreStation 1. Our aim is to demonstrate how the systematics of an interferometricmeasurement affect the quality of the calibrated data, how errors correlate andpropagate, and in the long run how this can lead to new calibration strategies.We present results of these simulations and the inversion process andextraction procedure. We also discuss some general properties of the coherencymatrix and Jones formalism that might prove useful in solving the calibrationproblem of aperture synthesis arrays. We conclude that even in the presence ofrealistic noise and instrumental errors, the statistical signature of the EoRsignal can be detected by LOFAR with relatively small errors. A detailed studyof the statistical properties of our data model and more complex instrumentalmodels will be considered in the future.

The LOFAR EoR Data Model: (I) Effects of Noise and Instrumental Corruptions on the 21-cm Reionization Signal-Extraction Strategy