HOW TO IDENTIFY AND SEPARATE BRIGHT GALAXY CLUSTERS FROM THE LOW-FREQUENCY RADIO SKY
文献类型：期刊论文
| 作者 | Wang, Jingying1 ; Xu, Haiguang1; Gu, Junhua1; An, Tao2; Cui, Haijuan1; Li, Jianxun3; Zhang, Zhongli4; Zheng, Qian5; Wu, Xiang-Ping5
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| 刊名 | ASTROPHYSICAL JOURNAL
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| 出版日期 | 2010-11-01 |
| 卷号 | 723期号:1页码:620-633 |
| 关键词 | dark ages, reionization, first stars early universe galaxies: clusters: general radio continuum: general techniques: image processing |
| 英文摘要 | In this work, we simulate the 50-200 MHz radio sky that is constrained in the field of view (5 degrees radius) of the 21 Centimeter Array (21CMA), a low-frequency radio interferometric array constructed in the remote area of Xinjiang, China, by carrying out Monte Carlo simulations to model the strong contaminating foreground of the redshifted cosmological reionization signals, including emissions from our Galaxy, galaxy clusters, and extragalactic discrete sources (i.e., star-forming galaxies, radio-quiet active galactic nuclei (AGNs), and radio-loud AGNs). As an improvement over previous works, we consider in detail not only random variations of morphological and spectroscopic parameters within the ranges allowed by multi-band observations, but also the evolution of radio halos in galaxy clusters, assuming that relativistic electrons are re-accelerated in the intracluster medium (ICM) in merger events and lose energy via both synchrotron emission and inverse Compton scattering with cosmic microwave background photons. By introducing a new approach designed on the basis of independent component analysis and wavelet detection algorithm, we prove that, with a cumulative observation of one month with the 21CMA array, about 80% of galaxy clusters (37 out of 48 clusters assuming a mean magnetic field of B = 2 mu G in the ICM, or 15 out of 18 clusters assuming B = 0.2 mu G) with central brightness temperatures of > 10 K at 65 MHz can be safely identified and separated from the overwhelmingly bright foreground. By examining the brightness temperature images and spectra extracted from these identified clusters, we find that the morphological and spectroscopic distortions are extremely small compared to the input simulated clusters, and the reduced chi(2) of brightness temperature profiles and spectra are controlled to be less than or similar to 0.5 and less than or similar to 1.3, respectively. These results robustly indicate that in the near future a sample of dozens of bright galaxy clusters will be disentangled from the foreground in 21CMA observations, the study of which will greatly improve our knowledge about cluster merger rates, electron acceleration mechanisms in cluster radio halos, and magnetic field in the ICM. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000284090100054 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/7762]  |
| 专题 | 国家天文台_星系宇宙学研究部 |
| 作者单位 | 1.Shanghai Jiao Tong Univ, Dept Phys, Shanghai 200240, Peoples R China 2.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China 3.Shanghai Jiao Tong Univ, Sch Elect Informat & Elect Engn, Shanghai 200240, Peoples R China 4.Max Planck Inst Astrophys, D-85741 Munich, Germany 5.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, Jingying,Xu, Haiguang,Gu, Junhua,et al. HOW TO IDENTIFY AND SEPARATE BRIGHT GALAXY CLUSTERS FROM THE LOW-FREQUENCY RADIO SKY[J]. ASTROPHYSICAL JOURNAL,2010,723(1):620-633. |
| APA | Wang, Jingying.,Xu, Haiguang.,Gu, Junhua.,An, Tao.,Cui, Haijuan.,...&Wu, Xiang-Ping.(2010).HOW TO IDENTIFY AND SEPARATE BRIGHT GALAXY CLUSTERS FROM THE LOW-FREQUENCY RADIO SKY.ASTROPHYSICAL JOURNAL,723(1),620-633. |
| MLA | Wang, Jingying,et al."HOW TO IDENTIFY AND SEPARATE BRIGHT GALAXY CLUSTERS FROM THE LOW-FREQUENCY RADIO SKY".ASTROPHYSICAL JOURNAL 723.1(2010):620-633. |
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来源：国家天文台
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