The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations

In this paper we present observations, simulations, and analysis demonstrating the direct connection between the location of foreground emission on the sky and its location in cosmological power spectra from interferometric redshifted 21 cm experiments. We begin with a heuristic formalism for unders...

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Main Authors:	Pober, J., Hazelton, B., Beardsley, A., Barry, N., Martinot, Z., Sullivan, I., Morales, M., Bell, M., Bernardi, G., Bhat, N., Bowman, J., Briggs, F., Cappall, R., Carroll, P., Corey, B., de Oliveira-Costar, A., Deshpande, A., Dillon, J., Emrich, D., Ewall-Wice, A., Feng, L., Goeke, R., Greenhill, L., Hewitt, J., Hindson, L., Hurley-Walker, N., Jacobs, D., Johnston-Hollitt, M., Kaplan, D., Kasper, J., Kim, H., Kittiwisit, P., Kratzenberg, E., Kudryavtseva, N., Lenc, E., Line, J., Loeb, A., Lonsdale, C., Lynch, M., McKinley, B., McWhirter, S., Mitchell, D., Morgan, E., Neben, A., Oberoi, D., Offringa, A., Ord, S., Paul, S., Pindor, B., Prabu, T., Procopio, P., Riding, J., Rogers, A., Roshi, A., Sethi, S., Shankar, N., Srivani, K., Subrahmanyan, R., Tegmark, M., Thyagarajan, N., Tingay, Steven, Trott, C., Waterson, M., Wayth, Randall, Webster, R., Whitney, A., Williams, A., Williams, C., Wyithe, J.
Format:	Journal Article
Published:	Institute of Physics Publishing 2016
Online Access:	http://hdl.handle.net/20.500.11937/16690

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author	Pober, J. Hazelton, B. Beardsley, A. Barry, N. Martinot, Z. Sullivan, I. Morales, M. Bell, M. Bernardi, G. Bhat, N. Bowman, J. Briggs, F. Cappall, R. Carroll, P. Corey, B. de Oliveira-Costar, A. Deshpande, A. Dillon, J. Emrich, D. Ewall-Wice, A. Feng, L. Goeke, R. Greenhill, L. Hewitt, J. Hindson, L. Hurley-Walker, N. Jacobs, D. Johnston-Hollitt, M. Kaplan, D. Kasper, J. Kim, H. Kittiwisit, P. Kratzenberg, E. Kudryavtseva, N. Lenc, E. Line, J. Loeb, A. Lonsdale, C. Lynch, M. McKinley, B. McWhirter, S. Mitchell, D. Morgan, E. Neben, A. Oberoi, D. Offringa, A. Ord, S. Paul, S. Pindor, B. Prabu, T. Procopio, P. Riding, J. Rogers, A. Roshi, A. Sethi, S. Shankar, N. Srivani, K. Subrahmanyan, R. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, C. Waterson, M. Wayth, Randall Webster, R. Whitney, A. Williams, A. Williams, C. Wyithe, J.
author_facet	Pober, J. Hazelton, B. Beardsley, A. Barry, N. Martinot, Z. Sullivan, I. Morales, M. Bell, M. Bernardi, G. Bhat, N. Bowman, J. Briggs, F. Cappall, R. Carroll, P. Corey, B. de Oliveira-Costar, A. Deshpande, A. Dillon, J. Emrich, D. Ewall-Wice, A. Feng, L. Goeke, R. Greenhill, L. Hewitt, J. Hindson, L. Hurley-Walker, N. Jacobs, D. Johnston-Hollitt, M. Kaplan, D. Kasper, J. Kim, H. Kittiwisit, P. Kratzenberg, E. Kudryavtseva, N. Lenc, E. Line, J. Loeb, A. Lonsdale, C. Lynch, M. McKinley, B. McWhirter, S. Mitchell, D. Morgan, E. Neben, A. Oberoi, D. Offringa, A. Ord, S. Paul, S. Pindor, B. Prabu, T. Procopio, P. Riding, J. Rogers, A. Roshi, A. Sethi, S. Shankar, N. Srivani, K. Subrahmanyan, R. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, C. Waterson, M. Wayth, Randall Webster, R. Whitney, A. Williams, A. Williams, C. Wyithe, J.
author_sort	Pober, J.
building	Curtin Institutional Repository
collection	Online Access
description	In this paper we present observations, simulations, and analysis demonstrating the direct connection between the location of foreground emission on the sky and its location in cosmological power spectra from interferometric redshifted 21 cm experiments. We begin with a heuristic formalism for understanding the mapping of sky coordinates into the cylindrically averaged power spectra measurements used by 21 cm experiments, with a focus on the effects of the instrument beam response and the associated sidelobes. We then demonstrate this mapping by analyzing power spectra with both simulated and observed data from the Murchison Widefield Array. We find that removing a foreground model which includes sources in both the main field-of-view and the first sidelobes reduces the contamination in high k_parallel modes by several percent relative to a model which only includes sources in the main field-of-view, with the completeness of the foreground model setting the principal limitation on the amount of power removed. While small, a percent-level amount of foreground power is in itself more than enough to prevent recovery of any EoR signal from these modes. This result demonstrates that foreground subtraction for redshifted 21 cm experiments is truly a wide-field problem, and algorithms and simulations must extend beyond the main instrument field-of-view to potentially recover the full 21 cm power spectrum.
first_indexed	2025-11-14T07:17:55Z
format	Journal Article
id	curtin-20.500.11937-16690
institution	Curtin University Malaysia
institution_category	Local University
last_indexed	2025-11-14T07:17:55Z
publishDate	2016
publisher	Institute of Physics Publishing
recordtype	eprints
repository_type	Digital Repository
spelling	curtin-20.500.11937-166902023-02-22T06:24:16Z The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations Pober, J. Hazelton, B. Beardsley, A. Barry, N. Martinot, Z. Sullivan, I. Morales, M. Bell, M. Bernardi, G. Bhat, N. Bowman, J. Briggs, F. Cappall, R. Carroll, P. Corey, B. de Oliveira-Costar, A. Deshpande, A. Dillon, J. Emrich, D. Ewall-Wice, A. Feng, L. Goeke, R. Greenhill, L. Hewitt, J. Hindson, L. Hurley-Walker, N. Jacobs, D. Johnston-Hollitt, M. Kaplan, D. Kasper, J. Kim, H. Kittiwisit, P. Kratzenberg, E. Kudryavtseva, N. Lenc, E. Line, J. Loeb, A. Lonsdale, C. Lynch, M. McKinley, B. McWhirter, S. Mitchell, D. Morgan, E. Neben, A. Oberoi, D. Offringa, A. Ord, S. Paul, S. Pindor, B. Prabu, T. Procopio, P. Riding, J. Rogers, A. Roshi, A. Sethi, S. Shankar, N. Srivani, K. Subrahmanyan, R. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, C. Waterson, M. Wayth, Randall Webster, R. Whitney, A. Williams, A. Williams, C. Wyithe, J. In this paper we present observations, simulations, and analysis demonstrating the direct connection between the location of foreground emission on the sky and its location in cosmological power spectra from interferometric redshifted 21 cm experiments. We begin with a heuristic formalism for understanding the mapping of sky coordinates into the cylindrically averaged power spectra measurements used by 21 cm experiments, with a focus on the effects of the instrument beam response and the associated sidelobes. We then demonstrate this mapping by analyzing power spectra with both simulated and observed data from the Murchison Widefield Array. We find that removing a foreground model which includes sources in both the main field-of-view and the first sidelobes reduces the contamination in high k_parallel modes by several percent relative to a model which only includes sources in the main field-of-view, with the completeness of the foreground model setting the principal limitation on the amount of power removed. While small, a percent-level amount of foreground power is in itself more than enough to prevent recovery of any EoR signal from these modes. This result demonstrates that foreground subtraction for redshifted 21 cm experiments is truly a wide-field problem, and algorithms and simulations must extend beyond the main instrument field-of-view to potentially recover the full 21 cm power spectrum. 2016 Journal Article http://hdl.handle.net/20.500.11937/16690 10.3847/0004-637X/819/1/8 Institute of Physics Publishing unknown
spellingShingle	Pober, J. Hazelton, B. Beardsley, A. Barry, N. Martinot, Z. Sullivan, I. Morales, M. Bell, M. Bernardi, G. Bhat, N. Bowman, J. Briggs, F. Cappall, R. Carroll, P. Corey, B. de Oliveira-Costar, A. Deshpande, A. Dillon, J. Emrich, D. Ewall-Wice, A. Feng, L. Goeke, R. Greenhill, L. Hewitt, J. Hindson, L. Hurley-Walker, N. Jacobs, D. Johnston-Hollitt, M. Kaplan, D. Kasper, J. Kim, H. Kittiwisit, P. Kratzenberg, E. Kudryavtseva, N. Lenc, E. Line, J. Loeb, A. Lonsdale, C. Lynch, M. McKinley, B. McWhirter, S. Mitchell, D. Morgan, E. Neben, A. Oberoi, D. Offringa, A. Ord, S. Paul, S. Pindor, B. Prabu, T. Procopio, P. Riding, J. Rogers, A. Roshi, A. Sethi, S. Shankar, N. Srivani, K. Subrahmanyan, R. Tegmark, M. Thyagarajan, N. Tingay, Steven Trott, C. Waterson, M. Wayth, Randall Webster, R. Whitney, A. Williams, A. Williams, C. Wyithe, J. The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title	The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title_full	The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title_fullStr	The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title_full_unstemmed	The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title_short	The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations
title_sort	importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early mwa epoch of reionization observations
url	http://hdl.handle.net/20.500.11937/16690

The importance of wide-field foreground removal for 21 cm cosmology: a demonstration with early MWA epoch of reionization observations

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