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Foreground removal using FastICA: A Showcase of the LOFAR-Epoch of Reionization experiment

Submitter: Vibor Jelic
Description: The LOFAR-EoR key science project will use the LOFAR telescope to detect the redshifted 21cm line of neutral hydrogen coming from the Epoch of Reionization (EoR). The EoR is a pivotal period in the history of the Universe during which the all-pervasive hydrogen gas was transformed from a neutral to an ionized state. It holds the key to structure formation and evolution, but also represents a missing piece of the puzzle in our current knowledge of the Universe.

One of the major astrophysical challenges of the EoR experiments is the extraction of the EoR signal from the prominent Galactic and extragalactic foregrounds (upper left image). Currently, there is no prevailing consensus on the most effective foreground removal method. In our recent paper (Chapman et al., submitted) the LOFAR-EoR team showed that the independent component analysis (ICA) algorithm, FASTICA, successfully removes the foregrounds with average fitting error of 0.5% (bottom left image). An advantage of this method is minimal prior knowledge of the form of the foregrounds at the exact resolution and frequency range of LOFAR. We also showed that 2D and 3D power spectra of the simulated EoR signal are recovered across the LOFAR frequency range (images on the right).

For more details please go to http://arxiv.org/abs/1201.2190 (arXiv:1201.2190).
Copyright: Chapman et al, submitted to MNRAS
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