论文标题
调查扩展无线电对电源时代时期的贡献
Investigating the Contribution of Extended Radio Sources to the Epoch of Reionisation Power Spectrum
论文作者
论文摘要
我们研究了诸如Centairus A和Galactic Supernova残余（SNR）等扩展无线电来源对我们从默里森（Murchison widefield）阵列（Murchison widefield（mwa））中检测统计$ 21 \，\ rm {cm} $信号的能力的贡献。这些来源通常被忽略，因为它们位于MWA主要光束的高度减弱的部分，但是在总尺度上，这些来源的总磁通密度为$ 10 \，\ rm {jy} $，我们希望检测到$ 21 \，\ rm {cm {cm} $信号。我们为银河系和半人马座A创建定制的多组分2D高斯模型，并模拟两个MWA快照观测值的可见性。我们将这些可见性网格引发，然后傅立叶相对于频率改变它们，平均它们在球面和圆柱形上平均产生1D和2D功率谱。我们将模拟的1D功率光谱与预期的$ 21 \，\ rm {cm} $功率谱进行比较。我们发现，尽管这些扩展的来源处于MWA初级光束模式的高度减弱的部分，但它们共同具有足够的功率（$ \ sim10^4-10^5 \，\ rm {mk^2} \，\，\，\ it {h^{ - 3}}} \ leq 0.1 h \ rm {mpc}^{ - 1} $禁止检测$ 21 \，\ rm {cm {cm} $ signal（$ 10^4 \，\ rm {mk^2}} \，\，\，\，\，\，\，\ it {h^3}}}}} \，\ rmmmmm {mpc^}我们发现，必须删除$ 50-90 \％的$ $ $，以便将泄漏降低到$ 21 \，\ rm {cm} $ Power Spectrum的$ 10-20 \％$的水平。广场扩展来源的效果将对MWA的21 \，\ rm {cm} $信号的可检测性以及未来的平方公里阵列（SKA）产生影响。
We investigate the contribution of extended radio sources such as Centaurus A, and Galactic supernova remnants (SNRs) to our ability to detect the statistical $21\,\rm{cm}$ signal from the Epoch of Reionisation (EoR) with the Murchison Widefield Array (MWA). These sources are typically ignored because they are in highly attenuated parts of the MWA primary beam, however in aggregate these sources have apparent flux densities of $10\,\rm{Jy}$ on angular scales we expect to detect the $21\,\rm{cm}$ signal. We create bespoke multi-component 2D Gaussian models for Galactic SNRs and for Centaurus A, and simulate the visibilities for two MWA snapshot observations. We grid those visibilities and then Fourier transform them with respect to frequency, averaging them both spherically and cylindrically to produce the 1D and 2D power spectra. We compare the simulated 1D power spectra to the expected $21\,\rm{cm}$ power spectrum. We find that although these extended sources are in highly attenuated parts of the MWA primary beam pattern, collectively they have enough power ($\sim10^4-10^5\,\rm{mK^2}\,\it{h^{-3}} \,\rm{Mpc^{3}}$) on EoR significant modes ($|\mathbf{k}| \leq 0.1 h \rm{Mpc}^{-1}$) to prohibit detection of the $21\,\rm{cm}$ signal ($10^4\,\rm{mK^2}\,\it{h^{-3}} \,\rm{Mpc^{3}}$). We find that $50-90\%$ of sources must be removed in order to reduce leakage to a level of $10-20\%$ of the $21\,\rm{cm}$ power spectrum on EoR significant modes. The effects of widefield extended sources will have implications on the detectability of the $21\,\rm{cm}$ signal for the MWA and with the future Square Kilometre Array (SKA).
