Contribution of Radio Halos to the Foreground for SKA EoR Experiments. (arXiv:1905.05399v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Li_W/0/1/0/all/0/1">Weitian Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_H/0/1/0/all/0/1">Haiguang Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ma_Z/0/1/0/all/0/1">Zhixian Ma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_D/0/1/0/all/0/1">Dan Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_Z/0/1/0/all/0/1">Zhenghao Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shan_C/0/1/0/all/0/1">Chenxi Shan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Jingying Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gu_J/0/1/0/all/0/1">Junhua Gu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_D/0/1/0/all/0/1">Dongchao Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lian_X/0/1/0/all/0/1">Xiaoli Lian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_Q/0/1/0/all/0/1">Qian Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Y/0/1/0/all/0/1">Yu Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_J/0/1/0/all/0/1">Jie Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_X/0/1/0/all/0/1">Xiang-Ping Wu</a>
The overwhelming foreground contamination is one of the primary impediments
to probing the EoR through measuring the redshifted 21 cm signal. Among various
foreground components, radio halos are less studied and their impacts on the
EoR observations are still poorly understood. In this work, we employ the
Press-Schechter formalism, merger-induced turbulent re-acceleration model, and
the latest SKA1-Low layout configuration to simulate the SKA “observed” images
of radio halos. We calculate the one-dimensional power spectra from simulated
images and find that radio halos can be about $10^4$, $10^3$ and $10^{2.5}$
times more luminous than the EoR signal on scales of $0.1,text{Mpc}^{-1} < k
< 2,text{Mpc}^{-1}$ in the 120-128, 154-162, and 192-200 MHz bands,
respectively. By examining the two-dimensional power spectra inside properly
defined EoR windows, we find that the power leaked by radio halos can still be
significant, as the power ratios of radio halos to the EoR signal on scales of
$0.5,text{Mpc}^{-1} lesssim k lesssim 1,text{Mpc}^{-1}$ can be up to
about 230-800%, 18-95%, and 7-40% in the three bands, when the 68%
uncertainties caused by the variation of the number density of bright radio
halos are considered. Furthermore, we find that radio halos located inside the
far side-lobes of the station beam can also impose strong contamination within
the EoR window. In conclusion, we argue that radio halos are severe foreground
sources and need serious treatments in future EoR experiments.
The overwhelming foreground contamination is one of the primary impediments
to probing the EoR through measuring the redshifted 21 cm signal. Among various
foreground components, radio halos are less studied and their impacts on the
EoR observations are still poorly understood. In this work, we employ the
Press-Schechter formalism, merger-induced turbulent re-acceleration model, and
the latest SKA1-Low layout configuration to simulate the SKA “observed” images
of radio halos. We calculate the one-dimensional power spectra from simulated
images and find that radio halos can be about $10^4$, $10^3$ and $10^{2.5}$
times more luminous than the EoR signal on scales of $0.1,text{Mpc}^{-1} < k
< 2,text{Mpc}^{-1}$ in the 120-128, 154-162, and 192-200 MHz bands,
respectively. By examining the two-dimensional power spectra inside properly
defined EoR windows, we find that the power leaked by radio halos can still be
significant, as the power ratios of radio halos to the EoR signal on scales of
$0.5,text{Mpc}^{-1} lesssim k lesssim 1,text{Mpc}^{-1}$ can be up to
about 230-800%, 18-95%, and 7-40% in the three bands, when the 68%
uncertainties caused by the variation of the number density of bright radio
halos are considered. Furthermore, we find that radio halos located inside the
far side-lobes of the station beam can also impose strong contamination within
the EoR window. In conclusion, we argue that radio halos are severe foreground
sources and need serious treatments in future EoR experiments.
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