Modelling and peeling extended sources with shapelets: A Fornax A case study
To make a power spectrum (PS) detection of the 21-cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with mu...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
CAMBRIDGE UNIV PRESS
2020
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| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/CE170100013 http://hdl.handle.net/20.500.11937/91569 |
| _version_ | 1848765550521483264 |
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| author | Line, Jack Mitchell, D.A. Pindor, B. Riding, J.L. McKinley, Ben Webster, R.L. Trott, Cathryn Hurley-Walker, Natasha Offringa, A.R. |
| author_facet | Line, Jack Mitchell, D.A. Pindor, B. Riding, J.L. McKinley, Ben Webster, R.L. Trott, Cathryn Hurley-Walker, Natasha Offringa, A.R. |
| author_sort | Line, Jack |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | To make a power spectrum (PS) detection of the 21-cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to 'shapelets', an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular resolution of the data is changed. We find that when increasing the angular resolution of the data, the MS CLEAN model worsens at large angular scales. When testing on real Murchison Widefield Array data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation, we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed. |
| first_indexed | 2025-11-14T11:37:02Z |
| format | Journal Article |
| id | curtin-20.500.11937-91569 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:37:02Z |
| publishDate | 2020 |
| publisher | CAMBRIDGE UNIV PRESS |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-915692023-05-16T03:34:59Z Modelling and peeling extended sources with shapelets: A Fornax A case study Line, Jack Mitchell, D.A. Pindor, B. Riding, J.L. McKinley, Ben Webster, R.L. Trott, Cathryn Hurley-Walker, Natasha Offringa, A.R. Science & Technology Physical Sciences Astronomy & Astrophysics astronomy data analysis giant radio galaxies GPU computing reionisation COSMIC DAWN RADIO REIONIZATION CALIBRATION SKY DECONVOLUTION SIMULATIONS EPOCH ARRAY astro-ph.IM astro-ph.IM astro-ph.CO To make a power spectrum (PS) detection of the 21-cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to 'shapelets', an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular resolution of the data is changed. We find that when increasing the angular resolution of the data, the MS CLEAN model worsens at large angular scales. When testing on real Murchison Widefield Array data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation, we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed. 2020 Journal Article http://hdl.handle.net/20.500.11937/91569 10.1017/pasa.2020.18 English http://purl.org/au-research/grants/arc/CE170100013 http://purl.org/au-research/grants/arc/FT180100321 http://creativecommons.org/licenses/by-nc-nd/4.0/ CAMBRIDGE UNIV PRESS fulltext |
| spellingShingle | Science & Technology Physical Sciences Astronomy & Astrophysics astronomy data analysis giant radio galaxies GPU computing reionisation COSMIC DAWN RADIO REIONIZATION CALIBRATION SKY DECONVOLUTION SIMULATIONS EPOCH ARRAY astro-ph.IM astro-ph.IM astro-ph.CO Line, Jack Mitchell, D.A. Pindor, B. Riding, J.L. McKinley, Ben Webster, R.L. Trott, Cathryn Hurley-Walker, Natasha Offringa, A.R. Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title | Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title_full | Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title_fullStr | Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title_full_unstemmed | Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title_short | Modelling and peeling extended sources with shapelets: A Fornax A case study |
| title_sort | modelling and peeling extended sources with shapelets: a fornax a case study |
| topic | Science & Technology Physical Sciences Astronomy & Astrophysics astronomy data analysis giant radio galaxies GPU computing reionisation COSMIC DAWN RADIO REIONIZATION CALIBRATION SKY DECONVOLUTION SIMULATIONS EPOCH ARRAY 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/20.500.11937/91569 |