BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE
Accurate antenna beam models are critical for radio observations aiming to isolate the redshifted 21 cm spectral line emission from the Dark Ages and the Epoch of Reionization (EOR) and unlock the scientific potential of 21 cm cosmology. Past work has focused on characterizing mean antenna beam mode...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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iop
2016
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| Online Access: | http://hdl.handle.net/1721.1/102669 https://orcid.org/0000-0002-4117-570X https://orcid.org/0000-0001-7776-7240 https://orcid.org/0000-0001-7130-208X https://orcid.org/0000-0003-3336-9958 |
| _version_ | 1826216018836455424 |
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| author | Neben, Abraham Richard Lonsdale, Colin John McWhirter, Stephen R. Williams, Christopher Leigh Hewitt, Jacqueline N Dillon, Joshua Shane Cappallo, Roger J Corey, Brian E Goeke, Robert F Morgan, Edward H |
| author2 | Haystack Observatory |
| author_facet | Haystack Observatory Neben, Abraham Richard Lonsdale, Colin John McWhirter, Stephen R. Williams, Christopher Leigh Hewitt, Jacqueline N Dillon, Joshua Shane Cappallo, Roger J Corey, Brian E Goeke, Robert F Morgan, Edward H |
| author_sort | Neben, Abraham Richard |
| collection | MIT |
| description | Accurate antenna beam models are critical for radio observations aiming to isolate the redshifted 21 cm spectral line emission from the Dark Ages and the Epoch of Reionization (EOR) and unlock the scientific potential of 21 cm cosmology. Past work has focused on characterizing mean antenna beam models using either satellite signals or astronomical sources as calibrators, but antenna-to-antenna variation due to imperfect instrumentation has remained unexplored. We characterize this variation for the Murchison Widefield Array (MWA) through laboratory measurements and simulations, finding typical deviations of the order of ±10%–20% near the edges of the main lobe and in the sidelobes. We consider the ramifications of these results for image- and power spectrum-based science. In particular, we simulate visibilities measured by a 100 m baseline and find that using an otherwise perfect foreground model, unmodeled beam-forming errors severely limit foreground subtraction accuracy within the region of Fourier space contaminated by foreground emission (the "wedge"). This region likely contains much of the cosmological signal, and accessing it will require measurement of per-antenna beam patterns. However, unmodeled beam-forming errors do not contaminate the Fourier space region expected to be free of foreground contamination (the "EOR window"), showing that foreground avoidance remains a viable strategy. |
| first_indexed | 2024-09-23T16:41:00Z |
| format | Article |
| id | mit-1721.1/102669 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:41:00Z |
| publishDate | 2016 |
| publisher | iop |
| record_format | dspace |
| spelling | mit-1721.1/1026692022-10-03T07:35:34Z BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE Neben, Abraham Richard Lonsdale, Colin John McWhirter, Stephen R. Williams, Christopher Leigh Hewitt, Jacqueline N Dillon, Joshua Shane Cappallo, Roger J Corey, Brian E Goeke, Robert F Morgan, Edward H Haystack Observatory Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Neben, Abraham Richard Hewitt, Jacqueline N. Dillon, Joshua S. Cappallo, Roger J. Corey, Brian E. Goeke, Robert F. Lonsdale, Colin John McWhirter, Stephen R. Morgan, Edward H. Williams, Christopher Leigh Accurate antenna beam models are critical for radio observations aiming to isolate the redshifted 21 cm spectral line emission from the Dark Ages and the Epoch of Reionization (EOR) and unlock the scientific potential of 21 cm cosmology. Past work has focused on characterizing mean antenna beam models using either satellite signals or astronomical sources as calibrators, but antenna-to-antenna variation due to imperfect instrumentation has remained unexplored. We characterize this variation for the Murchison Widefield Array (MWA) through laboratory measurements and simulations, finding typical deviations of the order of ±10%–20% near the edges of the main lobe and in the sidelobes. We consider the ramifications of these results for image- and power spectrum-based science. In particular, we simulate visibilities measured by a 100 m baseline and find that using an otherwise perfect foreground model, unmodeled beam-forming errors severely limit foreground subtraction accuracy within the region of Fourier space contaminated by foreground emission (the "wedge"). This region likely contains much of the cosmological signal, and accessing it will require measurement of per-antenna beam patterns. However, unmodeled beam-forming errors do not contaminate the Fourier space region expected to be free of foreground contamination (the "EOR window"), showing that foreground avoidance remains a viable strategy. National Science Foundation (U.S.) (Grant AST-0821321) Marble Astrophysics Fund Massachusetts Institute of Technology. School of Science 2016-05-24T23:44:46Z 2016-05-24T23:44:46Z 2016-03 2015-10 Article http://purl.org/eprint/type/JournalArticle 1538-4357 0004-637X http://hdl.handle.net/1721.1/102669 Neben, Abraham R., Jacqueline N. Hewitt, Richard F. Bradley, Joshua S. Dillon, G. Bernardi, J. D. Bowman, F. Briggs, et al. “BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE.” The Astrophysical Journal 820, no. 1 (March 17, 2016): 44. © 2016 The American Astronomical Society https://orcid.org/0000-0002-4117-570X https://orcid.org/0000-0001-7776-7240 https://orcid.org/0000-0001-7130-208X https://orcid.org/0000-0003-3336-9958 en_US http://dx.doi.org/10.3847/0004-637x/820/1/44 The Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf iop IOP Publishing |
| spellingShingle | Neben, Abraham Richard Lonsdale, Colin John McWhirter, Stephen R. Williams, Christopher Leigh Hewitt, Jacqueline N Dillon, Joshua Shane Cappallo, Roger J Corey, Brian E Goeke, Robert F Morgan, Edward H BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title | BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title_full | BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title_fullStr | BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title_full_unstemmed | BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title_short | BEAM-FORMING ERRORS IN MURCHISON WIDEFIELD ARRAY PHASED ARRAY ANTENNAS AND THEIR EFFECTS ON EPOCH OF REIONIZATION SCIENCE |
| title_sort | beam forming errors in murchison widefield array phased array antennas and their effects on epoch of reionization science |
| url | http://hdl.handle.net/1721.1/102669 https://orcid.org/0000-0002-4117-570X https://orcid.org/0000-0001-7776-7240 https://orcid.org/0000-0001-7130-208X https://orcid.org/0000-0003-3336-9958 |
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