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Multi-frequency ang...
Multi-frequency angular power spectrum of the 21 cm signal from the Epoch of Reionisation using the Murchison Widefield Array
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Trott, Cathryn M. (författare)
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- Mondal, Rajesh (författare)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC),Tel Aviv University, Israel
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- Mellema, Garrelt (författare)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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Murray, Steven G. (författare)
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Greig, Bradley (författare)
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Line, Jack L. B. (författare)
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Barry, Nichole (författare)
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Morales, Miguel F. (författare)
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(creator_code:org_t)
- 2022-10-13
- 2022
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 666
- Relaterad länk:
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Context. The Multi-frequency Angular Power Spectrum (MAPS) is an alternative to spherically averaged power spectra, and computes local fluctuations in the angular power spectrum without need for line-of-sight spectral transform.Aims. We aimed to test different approaches to MAPS and treatment of the foreground contamination, and compare with the spherically averaged power spectrum, and the single-frequency angular power spectrum.Methods. We applied the MAPS to 110 h of data in z = 6.2 − 7.5 obtained for the Murchison Widefield Array Epoch of Reionisation experiment to compute the statistical power of 21 cm brightness temperature fluctuations. In the presence of bright foregrounds, a filter was applied to remove large-scale modes prior to MAPS application, significantly reducing MAPS power due to systematics.Results. The MAPS showed a contrast of 102–103 to a simulated 21 cm cosmological signal for spectral separations of 0−4 MHz after application of the filter, reflecting results for the spherically averaged power spectrum. The single-frequency angular power spectrum was also computed. At z = 7.5 and l = 200, we found an angular power of 53 mK2, exceeding a simulated cosmological signal power by a factor of one thousand. Residual spectral structure, inherent to the calibrated data, and not spectral leakage from large-scale modes, was the dominant source of systematic power bias. The single-frequency angular power spectrum yielded slightly poorer results compared with the spherically averaged power spectrum, having applied a spectral filter to reduce foregrounds. Exploration of other filters may improve this result, along with consideration of wider bandwidths.
Ämnesord
- NATURVETENSKAP -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)
Nyckelord
- instrumentation
- interferometers
- methods
- statistical
- dark ages
- reionization
- first stars
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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