Simulations of ionospheric refraction on radio interferometric data
The Epoch of Reionisation (EoR) is the period within which the neutral universe transitioned to an ionised one. This period remains unobserved using low-frequency radio interferometers which target the 21 cm signal of neutral hydrogen emitted in this era. The Murchison Widefield Array (MWA) radio...
| Main Authors: | , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
CAMBRIDGE UNIV PRESS
2021
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2105.04215 http://hdl.handle.net/20.500.11937/91572 |
| _version_ | 1848765551510290432 |
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| author | Chege, J Kariuki Jordan, Chris Lynch, Christene Line, Jack Trott, Cathryn |
| author_facet | Chege, J Kariuki Jordan, Chris Lynch, Christene Line, Jack Trott, Cathryn |
| author_sort | Chege, J Kariuki |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The Epoch of Reionisation (EoR) is the period within which the neutral
universe transitioned to an ionised one. This period remains unobserved using
low-frequency radio interferometers which target the 21 cm signal of neutral
hydrogen emitted in this era. The Murchison Widefield Array (MWA) radio
telescope was built with the detection of this signal as one of its major
science goals. One of the most significant challenges towards a successful
detection is that of calibration, especially in the presence of the Earth's
ionosphere. By introducing refractive source shifts, distorting source shapes
and scintillating flux densities, the ionosphere is a major nuisance in
low-frequency radio astronomy. We introduce SIVIO, a software tool developed
for simulating observations of the MWA through different ionospheric conditions
estimated using thin screen approximation models and propagated into the
visibilities. This enables us to directly assess the impact of the ionosphere
on observed EoR data and the resulting power spectra. We show that the
simulated data captures the dispersive behaviour of ionospheric effects. We
show that the spatial structure of the simulated ionospheric media is
accurately reconstructed either from the resultant source positional offsets or
from parameters evaluated during the data calibration procedure. In turn, this
will inform on the best strategies of identifying and efficiently eliminating
ionospheric contamination in EoR data moving into the Square Kilometre Array
era. |
| first_indexed | 2025-11-14T11:37:03Z |
| format | Journal Article |
| id | curtin-20.500.11937-91572 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:37:03Z |
| publishDate | 2021 |
| publisher | CAMBRIDGE UNIV PRESS |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-915722023-05-16T05:18:26Z Simulations of ionospheric refraction on radio interferometric data Chege, J Kariuki Jordan, Chris Lynch, Christene Line, Jack Trott, Cathryn Science & Technology Physical Sciences Astronomy & Astrophysics atmospheric effects plasmas instrumentation interferometers Algorithms CALIBRATION EPOCH ARRAY astro-ph.IM astro-ph.IM astro-ph.GA The Epoch of Reionisation (EoR) is the period within which the neutral universe transitioned to an ionised one. This period remains unobserved using low-frequency radio interferometers which target the 21 cm signal of neutral hydrogen emitted in this era. The Murchison Widefield Array (MWA) radio telescope was built with the detection of this signal as one of its major science goals. One of the most significant challenges towards a successful detection is that of calibration, especially in the presence of the Earth's ionosphere. By introducing refractive source shifts, distorting source shapes and scintillating flux densities, the ionosphere is a major nuisance in low-frequency radio astronomy. We introduce SIVIO, a software tool developed for simulating observations of the MWA through different ionospheric conditions estimated using thin screen approximation models and propagated into the visibilities. This enables us to directly assess the impact of the ionosphere on observed EoR data and the resulting power spectra. We show that the simulated data captures the dispersive behaviour of ionospheric effects. We show that the spatial structure of the simulated ionospheric media is accurately reconstructed either from the resultant source positional offsets or from parameters evaluated during the data calibration procedure. In turn, this will inform on the best strategies of identifying and efficiently eliminating ionospheric contamination in EoR data moving into the Square Kilometre Array era. 2021 Journal Article http://hdl.handle.net/20.500.11937/91572 10.1017/pasa.2021.22 English https://arxiv.org/abs/2105.04215 http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/FT180100321 CAMBRIDGE UNIV PRESS restricted |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics atmospheric effects plasmas instrumentation interferometers Algorithms CALIBRATION EPOCH ARRAY astro-ph.IM astro-ph.IM astro-ph.GA Chege, J Kariuki Jordan, Chris Lynch, Christene Line, Jack Trott, Cathryn Simulations of ionospheric refraction on radio interferometric data |
| title | Simulations of ionospheric refraction on radio interferometric data |
| title_full | Simulations of ionospheric refraction on radio interferometric data |
| title_fullStr | Simulations of ionospheric refraction on radio interferometric data |
| title_full_unstemmed | Simulations of ionospheric refraction on radio interferometric data |
| title_short | Simulations of ionospheric refraction on radio interferometric data |
| title_sort | simulations of ionospheric refraction on radio interferometric data |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics atmospheric effects plasmas instrumentation interferometers Algorithms CALIBRATION EPOCH ARRAY astro-ph.IM astro-ph.IM astro-ph.GA |
| url | https://arxiv.org/abs/2105.04215 https://arxiv.org/abs/2105.04215 https://arxiv.org/abs/2105.04215 http://hdl.handle.net/20.500.11937/91572 |