CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA

Nithyanandan Thyagarajan; Daniel Jacobs; Judd Bowman; N. Barry; A. P. Beardsley; G. Bernardi; F. Briggs; R. J. Cappallo; P. Carroll; A. A. Deshpande; A. De Oliveira-Costa; Joshua S. Dillon; A. Ewall-Wice; L. Feng; L. J. Greenhill; B. J. Hazelton; L. Hernquist; J. N. Hewitt; N. Hurley-Walker; M. Johnston-Hollitt; D. L. Kaplan; Han Seek Kim; P. Kittiwisit; E. Lenc; J. Line; A. Loeb; C. J. Lonsdale; B. McKinley; S. R. McWhirter; D. A. Mitchell; M. F. Morales; E. Morgan; A. R. Neben; D. Oberoi; A. R. Offringa; S. M. Ord; Sourabh Paul; B. Pindor; J. C. Pober; T. Prabu; P. Procopio; J. Riding; N. Udaya Shankar; Shiv K. Sethi; K. S. Srivani; R. Subrahmanyan; I. S. Sullivan; M. Tegmark; S. J. Tingay; C. M. Trott; R. B. Wayth; R. L. Webster; A. Williams; C. L. Williams; J. S B Wyithe

doi:10.1088/2041-8205/807/2/L28

CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA

Nithyanandan Thyagarajan, Daniel Jacobs, Judd Bowman, N. Barry, A. P. Beardsley, G. Bernardi, F. Briggs, R. J. Cappallo, P. Carroll, A. A. Deshpande, A. De Oliveira-Costa, Joshua S. Dillon, A. Ewall-Wice, L. Feng, L. J. Greenhill, B. J. Hazelton, L. Hernquist, J. N. Hewitt, N. Hurley-Walker, M. Johnston-HollittD. L. Kaplan, Han Seek Kim, P. Kittiwisit, E. Lenc, J. Line, A. Loeb, C. J. Lonsdale, B. McKinley, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, A. R. Neben, D. Oberoi, A. R. Offringa, S. M. Ord, Sourabh Paul, B. Pindor, J. C. Pober, T. Prabu, P. Procopio, J. Riding, N. Udaya Shankar, Shiv K. Sethi, K. S. Srivani, R. Subrahmanyan, I. S. Sullivan, M. Tegmark, S. J. Tingay, C. M. Trott, R. B. Wayth, R. L. Webster, A. Williams, C. L. Williams, J. S B Wyithe

Earth and Space Exploration, School of (SESE)

Research output: Contribution to journal › Article › peer-review

75 Scopus citations

Abstract

We confirm our recent prediction of the "pitchfork" foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio >10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ∼40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.

Original language	English (US)
Article number	L28
Journal	Astrophysical Journal Letters
Volume	807
Issue number	2
DOIs	https://doi.org/10.1088/2041-8205/807/2/L28
State	Published - Jul 10 2015

Keywords

cosmology: observations
dark ages, reionization, first stars
large-scale structure of universe
methods: statistical
radio continuum: galaxies
techniques: interferometric

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/2041-8205/807/2/L28

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Thyagarajan, N., Jacobs, D., Bowman, J., Barry, N., Beardsley, A. P., Bernardi, G., Briggs, F., Cappallo, R. J., Carroll, P., Deshpande, A. A., De Oliveira-Costa, A., Dillon, J. S., Ewall-Wice, A., Feng, L., Greenhill, L. J., Hazelton, B. J., Hernquist, L., Hewitt, J. N., Hurley-Walker, N., ... Wyithe, J. S. B. (2015). CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA. Astrophysical Journal Letters, 807(2), Article L28. https://doi.org/10.1088/2041-8205/807/2/L28

Thyagarajan, N, Jacobs, D , Bowman, J, Barry, N, Beardsley, AP, Bernardi, G, Briggs, F, Cappallo, RJ, Carroll, P, Deshpande, AA, De Oliveira-Costa, A, Dillon, JS, Ewall-Wice, A, Feng, L, Greenhill, LJ, Hazelton, BJ, Hernquist, L, Hewitt, JN, Hurley-Walker, N, Johnston-Hollitt, M, Kaplan, DL, Kim, HS, Kittiwisit, P, Lenc, E, Line, J, Loeb, A, Lonsdale, CJ, McKinley, B, McWhirter, SR, Mitchell, DA, Morales, MF, Morgan, E, Neben, AR, Oberoi, D, Offringa, AR, Ord, SM, Paul, S, Pindor, B, Pober, JC, Prabu, T, Procopio, P, Riding, J, Shankar, NU, Sethi, SK, Srivani, KS, Subrahmanyan, R, Sullivan, IS, Tegmark, M, Tingay, SJ, Trott, CM, Wayth, RB, Webster, RL, Williams, A, Williams, CL & Wyithe, JSB 2015, 'CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA', Astrophysical Journal Letters, vol. 807, no. 2, L28. https://doi.org/10.1088/2041-8205/807/2/L28

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title = "CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA",

abstract = "We confirm our recent prediction of the {"}pitchfork{"} foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio >10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ∼40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.",

keywords = "cosmology: observations, dark ages, reionization, first stars, large-scale structure of universe, methods: statistical, radio continuum: galaxies, techniques: interferometric",

author = "Nithyanandan Thyagarajan and Daniel Jacobs and Judd Bowman and N. Barry and Beardsley, {A. P.} and G. Bernardi and F. Briggs and Cappallo, {R. J.} and P. Carroll and Deshpande, {A. A.} and {De Oliveira-Costa}, A. and Dillon, {Joshua S.} and A. Ewall-Wice and L. Feng and Greenhill, {L. J.} and Hazelton, {B. J.} and L. Hernquist and Hewitt, {J. N.} and N. Hurley-Walker and M. Johnston-Hollitt and Kaplan, {D. L.} and Kim, {Han Seek} and P. Kittiwisit and E. Lenc and J. Line and A. Loeb and Lonsdale, {C. J.} and B. McKinley and McWhirter, {S. R.} and Mitchell, {D. A.} and Morales, {M. F.} and E. Morgan and Neben, {A. R.} and D. Oberoi and Offringa, {A. R.} and Ord, {S. M.} and Sourabh Paul and B. Pindor and Pober, {J. C.} and T. Prabu and P. Procopio and J. Riding and Shankar, {N. Udaya} and Sethi, {Shiv K.} and Srivani, {K. S.} and R. Subrahmanyan and Sullivan, {I. S.} and M. Tegmark and Tingay, {S. J.} and Trott, {C. M.} and Wayth, {R. B.} and Webster, {R. L.} and A. Williams and Williams, {C. L.} and Wyithe, {J. S B}",

year = "2015",

month = jul,

day = "10",

doi = "10.1088/2041-8205/807/2/L28",

language = "English (US)",

volume = "807",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

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T1 - CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA

AU - Thyagarajan, Nithyanandan

AU - Jacobs, Daniel

AU - Bowman, Judd

AU - Barry, N.

AU - Beardsley, A. P.

AU - Bernardi, G.

AU - Briggs, F.

AU - Cappallo, R. J.

AU - Carroll, P.

AU - Deshpande, A. A.

AU - De Oliveira-Costa, A.

AU - Dillon, Joshua S.

AU - Ewall-Wice, A.

AU - Feng, L.

AU - Greenhill, L. J.

AU - Hazelton, B. J.

AU - Hernquist, L.

AU - Hewitt, J. N.

AU - Hurley-Walker, N.

AU - Johnston-Hollitt, M.

AU - Kaplan, D. L.

AU - Kim, Han Seek

AU - Kittiwisit, P.

AU - Lenc, E.

AU - Line, J.

AU - Loeb, A.

AU - Lonsdale, C. J.

AU - McKinley, B.

AU - McWhirter, S. R.

AU - Mitchell, D. A.

AU - Morales, M. F.

AU - Morgan, E.

AU - Neben, A. R.

AU - Oberoi, D.

AU - Offringa, A. R.

AU - Ord, S. M.

AU - Paul, Sourabh

AU - Pindor, B.

AU - Pober, J. C.

AU - Prabu, T.

AU - Procopio, P.

AU - Riding, J.

AU - Shankar, N. Udaya

AU - Sethi, Shiv K.

AU - Srivani, K. S.

AU - Subrahmanyan, R.

AU - Sullivan, I. S.

AU - Tegmark, M.

AU - Tingay, S. J.

AU - Trott, C. M.

AU - Wayth, R. B.

AU - Webster, R. L.

AU - Williams, A.

AU - Williams, C. L.

AU - Wyithe, J. S B

PY - 2015/7/10

Y1 - 2015/7/10

N2 - We confirm our recent prediction of the "pitchfork" foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio >10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ∼40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.

AB - We confirm our recent prediction of the "pitchfork" foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H i signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio >10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ∼40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum.

KW - cosmology: observations

KW - dark ages, reionization, first stars

KW - large-scale structure of universe

KW - methods: statistical

KW - radio continuum: galaxies

KW - techniques: interferometric

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UR - http://www.scopus.com/inward/citedby.url?scp=84937032205&partnerID=8YFLogxK

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SN - 2041-8205

VL - 807

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

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ER -

CONFIRMATION OF WIDE-FIELD SIGNATURES IN REDSHIFTED 21 cm POWER SPECTRA

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