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Robust Foregrounds Removal for 21-cm Experiments

Published online by Cambridge University Press:  08 May 2018

F. Mertens Open the ORCID record for F. Mertens [Opens in a new window] ,
A. Ghosh  and
L. V. E. Koopmans
F. Mertens
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, P. O. Box 800, 9700 AV Groningen, The Netherlands
A. Ghosh
Affiliation:
Department of Physics and Astronomy, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa Square Kilometre Array radio telescope (SKA) South Africa, The Park, Park Road, Cape Town 7405, South Africa
L. V. E. Koopmans
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, P. O. Box 800, 9700 AV Groningen, The Netherlands
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Abstract

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Direct detection of the Epoch of Reionization via the redshifted 21-cm line will have unprecedented implications on the study of structure formation in the early Universe. To fulfill this promise current and future 21-cm experiments will need to detect the weak 21-cm signal over foregrounds several order of magnitude greater. This requires accurate modeling of the galactic and extragalactic emission and of its contaminants due to instrument chromaticity, ionosphere and imperfect calibration. To solve for this complex modeling, we propose a new method based on Gaussian Process Regression (GPR) which is able to cleanly separate the cosmological signal from most of the foregrounds contaminants. We also propose a new imaging method based on a maximum likelihood framework which solves for the interferometric equation directly on the sphere. Using this method, chromatic effects causing the so-called “wedge” are effectively eliminated (i.e. deconvolved) in the cylindrical (k⊥, k∥) power spectrum.

Keywords

methods:data analysisstatistical; techniques:interferometric; cosmology: observationsearly universelarge-scale structure of universe
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 12 , Symposium S333: Peering towards Cosmic Dawn , October 2017 , pp. 284 - 287
Copyright
Copyright © International Astronomical Union 2018 

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