Study on 21 cm Signal of High Redshift Quasars

Q4 Physics and Astronomy

Chinese Astronomy and Astrophysics Pub Date : 2022-07-01 DOI:10.1016/j.chinastron.2022.09.005

XIANG Hong-bin , MA Qing-bo

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引用次数: 0

Abstract

We use the results of high resolution numerical simulations to fix the theoretical model of high redshift quasars (QSOs) ionizing and heating neutral gas, and predict the signal characteristics and signal/noise (S/N) ratios for Five-hundred-meter Aperture Spherical Telescope (FAST) to observe the 21 cm radiation around QSO. Our conclusions are summarized as: (1) the 21 cm frequency spectrum under the FAST field has full HII region for the QSO at $z = 8$ and with luminosity similar to ULAS J1120+0641, while has only a small trough for the QSO at $z = 10$ and with low luminosity; (2) the effect of Finite Light Travel Time (FLTT) obviously changes the 21 cm frequency spectrum of high redshift QSOs, makes the transition curve at lower frequency much steeper than that at higher frequency; (3) the FAST telescope can observe the 21 cm radiation of high redshift QSO with very high S/N ratio as high as $\sim 12$ , thus can identify the HII regions and the FLTT effect.

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高红移类星体21cm信号的研究

利用高分辨率数值模拟的结果，建立了高红移类星体电离加热中性气体的理论模型，并预测了500米口径球面望远镜(FAST)观测高红移类星体周围21 cm辐射的信号特征和信噪比。结果表明:(1)FAST场下的21 cm频谱在z=8处具有完整的HII区，亮度与ULAS J1120+0641相似，而在z=10处只有一个小波谷，亮度较低;(2)有限光行时间(FLTT)的作用明显改变了高红移qso的21 cm频谱，使得低频的跃迁曲线比高频的陡得多;(3) FAST望远镜可以观测到高红移QSO的21 cm辐射，信噪比高达~ 12，从而可以识别HII区域和FLTT效应。

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来源期刊

Chinese Astronomy and Astrophysics Physics and Astronomy-Astronomy and Astrophysics

CiteScore

0.70

自引率

0.00%

发文量

期刊介绍： The vigorous growth of astronomical and astrophysical science in China led to an increase in papers on astrophysics which Acta Astronomica Sinica could no longer absorb. Translations of papers from two new journals the Chinese Journal of Space Science and Acta Astrophysica Sinica are added to the translation of Acta Astronomica Sinica to form the new journal Chinese Astronomy and Astrophysics. Chinese Astronomy and Astrophysics brings English translations of notable articles to astronomers and astrophysicists outside China.