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Evaluating the QSO ...
Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn
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- Ross, Hannah E. (författare)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC),Lawrence Berkeley National Lab, USA; University of Sussex, UK
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Dixon, Keri L. (författare)
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- Ghara, Raghunath (författare)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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Iliev, Ilian T. (författare)
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- Mellema, Garrelt (författare)
- Stockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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(creator_code:org_t)
- 2019-05-04
- 2019
- Engelska.
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 487:1, s. 1101-1119
- Relaterad länk:
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http://arxiv.org/pdf...
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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
- The upcoming radio interferometer Square Kilometre Array (SKA) is expected to directly detect the redshifted 21-cm signal from the neutral hydrogen present during the Cosmic Dawn. Temperature fluctuations from X-ray heating of the neutral intergalactic medium can dominate the fluctuations in the 21-cm signal from this time. This heating depends on the abundance, clustering, and properties of the X-ray sources present, which remain highly uncertain. We present a suite of three new large-volume, 349 Mpc a side, fully numerical radiative transfer simulations including QSO-like sources, extending the work previously presented in Ross et al. (2017). The results show that our QSOs have a modest contribution to the heating budget, yet significantly impact the 21-cm signal. Initially, the power spectrum is boosted on large scales by heating from the biased QSO-like sources, before decreasing on all scales. Fluctuations from images of the 21-cm signal with resolutions corresponding to SKA1-Low at the appropriate redshifts are well above the expected noise for deep integrations, indicating that imaging could be feasible for all the X-ray source models considered. The most notable contribution of the QSOs is a dramatic increase in non-Gaussianity of the signal, as measured by the skewness and kurtosis of the 21-cm probability distribution functions. However, in the case of late Lyman-alpha saturation, this non-Gaussianity could be dramatically decreased particularly when heating occurs earlier. We conclude that increased non-Gaussianity is a promising signature of rare X-ray sources at this time, provided that Lyman-a saturation occurs before heating dominates the 21-cm signal.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- radiative transfer
- cosmology: dark ages
- reionizaion
- first stars
- galaxies: quasars: general
- intergalactic medium
- cosmology: theory
- cosmology: large-scale structure of Universe
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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