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HOW TO IDENTIFY AND SEPARATE BRIGHT GALAXY CLUSTERS FROM THE LOW-FREQUENCY RADIO SKY
Wang, Jingying1; Xu, Haiguang1; Gu, Junhua1; An, Tao2; Cui, Haijuan1; Li, Jianxun3; Zhang, Zhongli4; Zheng, Qian5; Wu, Xiang-Ping5
2010-11-01
Source PublicationASTROPHYSICAL JOURNAL
Volume723Issue:1Pages:620-633
AbstractIn 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.
KeywordEarly Universe Dark Ages Galaxies: Clusters: General Reionization Radio Continuum: General First Stars Techniques: Image Processing
DOI10.1088/0004-637X/723/1/620
Indexed BySCI
Language英语
WOS IDWOS:000284090100054
Citation statistics
Cited Times:8[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/7762
Collection星系宇宙学研究部
Affiliation1.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
Recommended Citation
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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