Detection and extraction of signals from the epoch of reionization using higher-order one-point statistics |
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| Authors: | Geraint J A Harker Saleem Zaroubi Rajat M Thomas Vibor Jeli&#; Panagiotis Labropoulos Garrelt Mellema Ilian T Iliev Gianni Bernardi Michiel A Brentjens A G de Bruyn Benedetta Ciardi Leon V E Koopmans V N Pandey reas H Pawlik Joop Schaye Sarod Yatawatta |
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| Institution: | Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700AV Groningen, the Netherlands;Department of Astronomy, Alba Nova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden;Institute for Theoretical Physics, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland;ASTRON, Postbus 2, 7990AA Dwingeloo, the Netherlands;Max-Planck Institute for Astrophysics, Karl-Schwarzschild-Straße 1, 85748 Garching, Germany;Leiden Observatory, Leiden University, PO Box 9513, 2300RA Leiden, the Netherlands |
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| Abstract: | Detecting redshifted 21-cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract the cosmological signal (CS) from foregrounds and noise which are orders of magnitude larger. Fortunately, the signal has some characteristics which differentiate it from the foregrounds and noise, and we suggest that using the correct statistics may tease out signatures of reionization. We generate mock data cubes simulating the output of the Low Frequency Array (LOFAR) EoR experiment. These cubes combine realistic models for Galactic and extragalactic foregrounds and the noise with three different simulations of the CS. We fit out the foregrounds, which are smooth in the frequency direction, to produce residual images in each frequency band. We denoise these images and study the skewness of the one-point distribution in the images as a function of frequency. We find that, under sufficiently optimistic assumptions, we can recover the main features of the redshift evolution of the skewness in the 21-cm signal. We argue that some of these features – such as a dip at the onset of reionization, followed by a rise towards its later stages – may be generic, and give us a promising route to a statistical detection of reionization. |
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| Keywords: | methods: statistical cosmology: theory diffuse radiation radio lines: general |
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