A candidate field for deep imaging of the Epoch of Reionization observed with MWA
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arXiv
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| Autores principales: | , , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866908445762912256 |
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| author | Zhang, Xueying Zheng, Qian Wu, Linhui Guo, Quan Duchesne, Stefan W. He, Mengfan Shan, Huanyuan Wu, Xiang-ping Johnston-Hollitt, Melanie Zhao, Feiyu Ma, Qingyuan |
| author_facet | Zhang, Xueying Zheng, Qian Wu, Linhui Guo, Quan Duchesne, Stefan W. He, Mengfan Shan, Huanyuan Wu, Xiang-ping Johnston-Hollitt, Melanie Zhao, Feiyu Ma, Qingyuan |
| contents | Deep imaging of structures from the Cosmic Dawn (CD) and the Epoch of Reionization (EoR) in five targeted fields is one of the highest priority scientific objectives for the Square Kilometre Array (SKA). Selecting 'quiet' fields, which allow deep imaging, is critical for future SKA CD/EoR observations. Pre-observations using existing radio facilities will help estimate the computational capabilities required for optimal data quality and refine data reduction techniques. In this study, we utilize data from the Murchison Widefield Array (MWA) Phase II extended array for a selected field to study the properties of foregrounds. We conduct deep imaging across two frequency bands: 72-103 MHz and 200-231 MHz. We identify up to 2,576 radio sources within a 5-degree radius of the image center (at RA (J2000) $8^h$ , Dec (J2000) 5°), achieving approximately 80% completeness at 7.7 mJy and 90% at 10.4 mJy for 216 MHz, with a total integration time of 4.43 hours and an average RMS of 1.80 mJy. Additionally, we apply a foreground removal algorithm using Principal Component Analysis (PCA) and calculate the angular power spectra of the residual images. Our results indicate that nearly all resolved radio sources can be successfully removed using PCA, leading to a reduction in foreground power. However, the angular power spectra of the residual map remains over an order of magnitude higher than the theoretically predicted CD/EoR 21 cm signal. Further improvements in data reduction and foreground subtraction techniques will be necessary to enhance these results. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_08048 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A candidate field for deep imaging of the Epoch of Reionization observed with MWA Zhang, Xueying Zheng, Qian Wu, Linhui Guo, Quan Duchesne, Stefan W. He, Mengfan Shan, Huanyuan Wu, Xiang-ping Johnston-Hollitt, Melanie Zhao, Feiyu Ma, Qingyuan Instrumentation and Methods for Astrophysics Cosmology and Nongalactic Astrophysics Deep imaging of structures from the Cosmic Dawn (CD) and the Epoch of Reionization (EoR) in five targeted fields is one of the highest priority scientific objectives for the Square Kilometre Array (SKA). Selecting 'quiet' fields, which allow deep imaging, is critical for future SKA CD/EoR observations. Pre-observations using existing radio facilities will help estimate the computational capabilities required for optimal data quality and refine data reduction techniques. In this study, we utilize data from the Murchison Widefield Array (MWA) Phase II extended array for a selected field to study the properties of foregrounds. We conduct deep imaging across two frequency bands: 72-103 MHz and 200-231 MHz. We identify up to 2,576 radio sources within a 5-degree radius of the image center (at RA (J2000) $8^h$ , Dec (J2000) 5°), achieving approximately 80% completeness at 7.7 mJy and 90% at 10.4 mJy for 216 MHz, with a total integration time of 4.43 hours and an average RMS of 1.80 mJy. Additionally, we apply a foreground removal algorithm using Principal Component Analysis (PCA) and calculate the angular power spectra of the residual images. Our results indicate that nearly all resolved radio sources can be successfully removed using PCA, leading to a reduction in foreground power. However, the angular power spectra of the residual map remains over an order of magnitude higher than the theoretically predicted CD/EoR 21 cm signal. Further improvements in data reduction and foreground subtraction techniques will be necessary to enhance these results. |
| title | A candidate field for deep imaging of the Epoch of Reionization observed with MWA |
| topic | Instrumentation and Methods for Astrophysics Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2507.08048 |