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Polarization leakag...
Polarization leakage in epoch of reionization windows - I. Low Frequency Array observations of the 3C196 field
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Asad, K. M. B. (author)
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Koopmans, L. V. E. (author)
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Jelic, V. (author)
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Pandey, V. N. (author)
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Ghosh, A. (author)
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Abdalla, F. B. (author)
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Bernardi, G. (author)
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Brentjens, M. A. (author)
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de Bruyn, A. G. (author)
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Bus, S. (author)
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Ciardi, B. (author)
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Chapman, E. (author)
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Daiboo, S. (author)
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Fernandez, E. R. (author)
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Harker, G. (author)
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Iliev, I. T. (author)
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- Jensen, Hannes (author)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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Martinez-Rubi, O. (author)
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- Mellema, Garrelt (author)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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Mevius, M. (author)
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Offringa, A. R. (author)
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Patil, A. H. (author)
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Schaye, J. (author)
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Thomas, R. M. (author)
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van der Tol, S. (author)
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Vedantham, H. K. (author)
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Yatawatta, S. (author)
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Zaroubi, S. (author)
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(creator_code:org_t)
- 2015-06-29
- 2015
- English.
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 451:4, s. 3709-3727
- Related links:
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https://academic.oup...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
Close
- Detection of the 21-cm signal coming from the epoch of reionization (EoR) is challenging especially because, even after removing the foregrounds, the residual Stokes I maps contain leakage from polarized emission that can mimic the signal. Here, we discuss the instrumental polarization of Low Frequency Array (LOFAR) and present realistic simulations of the leakages between Stokes parameters. From the LOFAR observations of polarized emission in the 3C196 field, we have quantified the level of polarization leakage caused by the nominal model beam of LOFAR, and compared it with the EoR signal using power spectrum analysis. We found that at 134-166 MHz, within the central 4A degrees of the field the (Q, U) -> I leakage power is lower than the EoR signal at k < 0.3 Mpc(-1). The leakage was found to be localized around a Faraday depth of 0, and the rms of the leakage as a fraction of the rms of the polarized emission was shown to vary between 0.2 and 0.3 per cent, both of which could be utilized in the removal of leakage. Moreover, we could define an 'EoR window' in terms of the polarization leakage in the cylindrical power spectrum above the point spread function (PSF)-induced wedge and below k(ayen) similar to 0.5 Mpc(-1), and the window extended up to k(ayen) similar to 1 Mpc(-1) at all k(aSyen) when 70 per cent of the leakage had been removed. These LOFAR results show that even a modest polarimetric calibration over a field of view of a parts per thousand(2) 4A degrees in the future arrays like Square Kilometre Array will ensure that the polarization leakage remains well below the expected EoR signal at the scales of 0.02-1 Mpc(-1).
Subject headings
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Keyword
- polarization
- instrumentation: polarimeters
- intergalactic medium
- cosmology: observations
- dark ages
- reionization
- first stars
Publication and Content Type
- ref (subject category)
- art (subject category)
Find in a library
To the university's database
- By the author/editor
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Asad, K. M. B.
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Koopmans, L. V. ...
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Jelic, V.
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Pandey, V. N.
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Ghosh, A.
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Abdalla, F. B.
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show more...
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Bernardi, G.
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Brentjens, M. A.
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de Bruyn, A. G.
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Bus, S.
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Ciardi, B.
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Chapman, E.
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Daiboo, S.
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Fernandez, E. R.
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Harker, G.
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Iliev, I. T.
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Jensen, Hannes
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Martinez-Rubi, O ...
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Mellema, Garrelt
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Mevius, M.
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Offringa, A. R.
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Patil, A. H.
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Schaye, J.
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Thomas, R. M.
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van der Tol, S.
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Vedantham, H. K.
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Yatawatta, S.
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Zaroubi, S.
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show less...
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- NATURAL SCIENCES
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NATURAL SCIENCES
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Stockholm University