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The first power spe...
The first power spectrum limit on the 21-cm signal of neutral hydrogen during the Cosmic Dawn at z=20-25 from LOFAR
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Gehlot, B. K. (author)
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Mertens, F. G. (author)
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Koopmans, L. V. E. (author)
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Brentjens, M. A. (author)
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Zaroubi, S. (author)
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Ciardi, B. (author)
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Ghosh, A. (author)
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Hatef, M. (author)
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Iliev, I. T. (author)
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Jelić, V. (author)
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Kooistra, R. (author)
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Krause, F. (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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Mitra, M. (author)
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Offringa, A. R. (author)
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Pandey, V. N. (author)
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Sardarabadi, A. M. (author)
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Schaye, J. (author)
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Silva, M. B. (author)
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Vedantham, H. K. (author)
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Yatawatta, S. (author)
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(creator_code:org_t)
- 2019-07-12
- 2019
- English.
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 488:3, s. 4271-4287
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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
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- Observations of the redshifted 21-cm hyperfine line of neutral hydrogen from early phases of the Universe such as Cosmic Dawn and the Epoch of Reionization promise to open a new window onto the early formation of stars and galaxies. We present the first upper limits on the power spectrum of redshifted 21-cm brightness temperature fluctuations in the redshift range z = 19.8-25.2 (54-68 MHz frequency range) using 14 h of data obtained with the LOFAR-Low Band Antenna (LBA) array. We also demonstrate the application of a multiple pointing calibration technique to calibrate the LOFAR-LBA dual-pointing observations centred on the North Celestial Pole and the radio galaxy 3C220.3, We observe an unexplained excess of similar to 30-50 per cent in Stokes / noise compared to Stokes V for the two observed fields, which decorrelates on greater than or similar to 12 s and might have a physical origin. We show that enforcing smoothness of gain errors along frequency direction during calibration reduces the additional variance in Stokes I compared Stokes V introduced by the calibration on sub-band level. After subtraction of smooth foregrounds, we achieve a 2 sigma upper limit on the 21-cm power spectrum of Delta(2)(21) < (14561 mK)(2) at k similar to 0.038 h cMpc(-1) and Delta(2)(21) < (14886 mK)(2) at k 0.038 h cMpc(-1) for the 3C220 and NCP fields respectively and both upper limits are consistent with each other. The upper limits for the two fields are still dominated by systematics on most k modes.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Keyword
- methods: data analysis
- methods: statistical
- techniques: interferometric
- dark ages
- reionization
- first stars
- diffuse radiation
- radio lines: general
Publication and Content Type
- ref (subject category)
- art (subject category)
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- By the author/editor
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Gehlot, B. K.
-
Mertens, F. G.
-
Koopmans, L. V. ...
-
Brentjens, M. A.
-
Zaroubi, S.
-
Ciardi, B.
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show more...
-
Ghosh, A.
-
Hatef, M.
-
Iliev, I. T.
-
Jelić, V.
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Kooistra, R.
-
Krause, F.
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Mellema, Garrelt
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Mevius, M.
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Mitra, M.
-
Offringa, A. R.
-
Pandey, V. N.
-
Sardarabadi, A. ...
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Schaye, J.
-
Silva, M. B.
-
Vedantham, H. K.
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Yatawatta, S.
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show less...
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Stockholm University