Empirical covariance modeling for 21 cm power spectrum estimation: A method demonstration and new limits from early Murchison Widefield Array 128-tile data EMPIRICAL COVARIANCE MODELING for 21 CM POWER .. JOSHUA S. DILLON et al.

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

Research output: Contribution to journalArticle

67 Scopus citations

Abstract

The separation of the faint cosmological background signal from bright astrophysical foregrounds remains one of the most daunting challenges of mapping the high-redshift intergalactic medium with the redshifted 21 cm line of neutral hydrogen. Advances in mapping and modeling of diffuse and point source foregrounds have improved subtraction accuracy, but no subtraction scheme is perfect. Precisely quantifying the errors and error correlations due to missubtracted foregrounds allows for both the rigorous analysis of the 21 cm power spectrum and for the maximal isolation of the "EoR window" from foreground contamination. We present a method to infer the covariance of foreground residuals from the data itself in contrast to previous attempts at a priori modeling. We demonstrate our method by setting limits on the power spectrum using a 3 h integration from the 128-tile Murchison Widefield Array. Observing between 167 and 198 MHz, we find at 95% confidence a best limit of Δ2(k)<3.7×104mK2 at comoving scale k=0.18hMpc-1 and at z=6.8, consistent with existing limits.

Original languageEnglish (US)
Article number123011
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume91
Issue number12
DOIs
StatePublished - Jun 19 2015

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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    Dillon, J. S., Neben, A. R., Hewitt, J. N., Tegmark, M., Barry, N., Beardsley, A. P., Bowman, J., Briggs, F., Carroll, P., De Oliveira-Costa, A., Ewall-Wice, A., Feng, L., Greenhill, L. J., Hazelton, B. J., Hernquist, L., Hurley-Walker, N., Jacobs, D., Kim, H. S., Kittiwisit, P., ... Williams, C. L. (2015). Empirical covariance modeling for 21 cm power spectrum estimation: A method demonstration and new limits from early Murchison Widefield Array 128-tile data EMPIRICAL COVARIANCE MODELING for 21 CM POWER .. JOSHUA S. DILLON et al. Physical Review D - Particles, Fields, Gravitation and Cosmology, 91(12), [123011]. https://doi.org/10.1103/PhysRevD.91.123011