Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations
Detecting a signal from the Epoch of Reionization (EoR) requires an exquisite understanding of Galactic and extragalactic foregrounds, low-frequency radio instruments, instrumental calibration, and data analysis pipelines. In this work, we build upon existing work that aims to understand the impact...
| Main Authors: | , , , |
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| Format: | Journal Article |
| Language: | English |
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OXFORD UNIV PRESS
2020
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| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/CE170100013 http://hdl.handle.net/20.500.11937/91567 |
| _version_ | 1848765549809500160 |
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| author | Joseph, R.C. Trott, Cathryn Wayth, Randall Nasirudin, A. |
| author_facet | Joseph, R.C. Trott, Cathryn Wayth, Randall Nasirudin, A. |
| author_sort | Joseph, R.C. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Detecting a signal from the Epoch of Reionization (EoR) requires an exquisite understanding of Galactic and extragalactic foregrounds, low-frequency radio instruments, instrumental calibration, and data analysis pipelines. In this work, we build upon existing work that aims to understand the impact of calibration errors on 21-cm power spectrum (PS) measurements. It is well established that calibration errors have the potential to inhibit EoR detections by introducing additional spectral features that mimic the structure of EoR signals. We present a straightforward way to estimate the impact of a wide variety of modelling residuals in EoR PS estimation. We apply this framework to the specific case of broken dipoles in Murchison Widefield Array (MWA) to understand its effect and estimate its impact on PS estimation. Combining an estimate of the percentage of MWA tiles that have at least one broken dipole (15-40 per cent) with an analytic description of beam errors induced by such dipoles, we compute the residuals of the foregrounds after calibration and source subtraction. We find that that incorrect beam modelling introduces bias in the 2D-PS on the order of ∼ 103 mK2 h−3 Mpc3. Although this is three orders of magnitude lower than current lowest limits, it is two orders of magnitude higher than the expected signal. Determining the accuracy of both current beam models and direction-dependent calibration pipelines is therefore crucial in our search for an EoR signal. |
| first_indexed | 2025-11-14T11:37:01Z |
| format | Journal Article |
| id | curtin-20.500.11937-91567 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:37:01Z |
| publishDate | 2020 |
| publisher | OXFORD UNIV PRESS |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-915672023-05-11T03:30:50Z Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations Joseph, R.C. Trott, Cathryn Wayth, Randall Nasirudin, A. Science & Technology Physical Sciences Astronomy & Astrophysics instrumentation: interferometers methods: statistical techniques: interferometric dark ages, reionization, first stars RADIO INTERFEROMETERS REIONIZATION SIMULATIONS EVOLUTION EPOCH ARRAY LINE astro-ph.IM astro-ph.IM astro-ph.CO Detecting a signal from the Epoch of Reionization (EoR) requires an exquisite understanding of Galactic and extragalactic foregrounds, low-frequency radio instruments, instrumental calibration, and data analysis pipelines. In this work, we build upon existing work that aims to understand the impact of calibration errors on 21-cm power spectrum (PS) measurements. It is well established that calibration errors have the potential to inhibit EoR detections by introducing additional spectral features that mimic the structure of EoR signals. We present a straightforward way to estimate the impact of a wide variety of modelling residuals in EoR PS estimation. We apply this framework to the specific case of broken dipoles in Murchison Widefield Array (MWA) to understand its effect and estimate its impact on PS estimation. Combining an estimate of the percentage of MWA tiles that have at least one broken dipole (15-40 per cent) with an analytic description of beam errors induced by such dipoles, we compute the residuals of the foregrounds after calibration and source subtraction. We find that that incorrect beam modelling introduces bias in the 2D-PS on the order of ∼ 103 mK2 h−3 Mpc3. Although this is three orders of magnitude lower than current lowest limits, it is two orders of magnitude higher than the expected signal. Determining the accuracy of both current beam models and direction-dependent calibration pipelines is therefore crucial in our search for an EoR signal. 2020 Journal Article http://hdl.handle.net/20.500.11937/91567 10.1093/mnras/stz3375 English http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/FT180100321 OXFORD UNIV PRESS fulltext |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics instrumentation: interferometers methods: statistical techniques: interferometric dark ages, reionization, first stars RADIO INTERFEROMETERS REIONIZATION SIMULATIONS EVOLUTION EPOCH ARRAY LINE astro-ph.IM astro-ph.IM astro-ph.CO Joseph, R.C. Trott, Cathryn Wayth, Randall Nasirudin, A. Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title | Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title_full | Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title_fullStr | Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title_full_unstemmed | Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title_short | Calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| title_sort | calibration and 21-cm power spectrum estimation in the presence of antenna beam variations |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics instrumentation: interferometers methods: statistical techniques: interferometric dark ages, reionization, first stars RADIO INTERFEROMETERS REIONIZATION SIMULATIONS EVOLUTION EPOCH ARRAY LINE astro-ph.IM astro-ph.IM astro-ph.CO |
| url | http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/CE170100013 http://hdl.handle.net/20.500.11937/91567 |