期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 442, 期 2, 页码 1491-1506出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stu927
关键词
methods: numerical; methods: statistical; cosmology: theory; dark ages; reionization; first stars; diffuse radiation
资金
- Department of Science and Technology (DST), India [SR/FTP/PS-119/2012]
- Swedish Research Council (VR) through the Oscar Klein Centre [2007-8709]
- Swedish Research Council [2012-4144]
- ANR within the Investissements d'Avenir programme [ANR-11-IDEX-0004-02]
- US NSF [AST-0708176, AST-1009799]
- NASA [NNX07AH09G, NNX11AE09G]
- NRF
- Korean government MEST [2012R1A1A1014646]
- Science and Technology Facilities Council [ST/F002858/1 and ST/I000976/1]
- Southeast Physics Network (SEPNet)
- US NSF TeraGrid/XSEDE [AST090005]
- National Science Foundation through TACC
- National Institute for Computational Sciences (NICS)
- ICG
- SEPNet
- University of Portsmouth
- Canada Foundation for Innovation under the auspices of Compute Canada
- Government of Ontario, Ontario Research Fund - Research Excellence
- University of Toronto
- STFC [ST/I000976/1, ST/L000652/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/L000652/1, ST/I000976/1] Funding Source: researchfish
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1009799] Funding Source: National Science Foundation
- National Research Foundation of Korea [2012R1A1A1014646] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Measurements of the H i 21-cm power spectra from the reionization epoch will be influenced by the evolution of the signal along the line-of-sight direction of any observed volume. We use numerical as well as seminumerical simulations of reionization in a cubic volume of 607 Mpc across to study this so-called light-cone effect on the H i 21-cm power spectrum. We find that the light-cone effect has the largest impact at two different stages of reionization: one when reionization is similar to 20 per cent and other when it is similar to 80 per cent completed. We find a factor of similar to 4 amplification of the power spectrum at the largest scale available in our simulations. We do not find any significant anisotropy in the 21-cm power spectrum due to the light-cone effect. We argue that for the power spectrum to become anisotropic, the light-cone effect would have to make the ionized bubbles significantly elongated or compressed along the line of sight, which would require extreme reionization scenarios. We also calculate the two-point correlation functions parallel and perpendicular to the line of sight and find them to differ. Finally, we calculate an optimum frequency bandwidth below which the light-cone effect can be neglected when extracting power spectra from observations. We find that if one is willing to accept a 10 per cent error due to the light-cone effect, the optimum frequency bandwidth for k = 0.056 Mpc(-1) is similar to 7.5 MHz. For k = 0.15 and 0.41 Mpc(-1), the optimum bandwidth is similar to 11 and similar to 16 MHz, respectively.
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