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Determination of z ∼ 0.8 neutral hydrogen fluctuations using the 21 cm intensity mapping autocorrelation

Switzer, E. R. ; Masui, K. W. ; Bandura, K. ; Calin, L.-M. ; Chang, T.-C. ; Chen, X.-L. ; Li, Y.-C. ; Liao, Y.-W. ; Natarajan, A. ; Pen, U.-L. ; Peterson, J. B. ; Shaw, J. R. ; Voytek, T. C.

Monthly notices of the Royal Astronomical Society. Letters, 2013-09, Vol.434 (1), p.L46-L50 [Revista revisada por pares]

Oxford University Press

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Título:
Determination of z ∼ 0.8 neutral hydrogen fluctuations using the 21 cm intensity mapping autocorrelation
Autor: Switzer, E. R. ; Masui, K. W. ; Bandura, K. ; Calin, L.-M. ; Chang, T.-C. ; Chen, X.-L. ; Li, Y.-C. ; Liao, Y.-W. ; Natarajan, A. ; Pen, U.-L. ; Peterson, J. B. ; Shaw, J. R. ; Voytek, T. C.
Es parte de: Monthly notices of the Royal Astronomical Society. Letters, 2013-09, Vol.434 (1), p.L46-L50
Descripción: The large-scale distribution of neutral hydrogen in the Universe will be luminous through its 21 cm emission. Here, for the first time, we use the auto-power spectrum of 21 cm intensity fluctuations to constrain neutral hydrogen fluctuations at z ∼ 0.8. Our data were acquired with the Green Bank Telescope and span the redshift range 0.6 < z < 1 over two fields totalling 41 deg2 and 190 h of radio integration time. The dominant synchrotron foregrounds exceed the signal by ∼103, but have fewer degrees of freedom and can be removed efficiently. Even in the presence of residual foregrounds, the auto-power can still be interpreted as an upper bound on the 21 cm signal. Our previous measurements of the cross-correlation of 21 cm intensity and the WiggleZ galaxy survey provide a lower bound. Through a Bayesian treatment of signal and foregrounds, we can combine both fields in auto- and cross-power into a measurement of ΩHI bHI = [0.62+0.23 −0.15] × 10−3 at 68 per cent confidence with 9 per cent systematic calibration uncertainty, where ΩHI is the neutral hydrogen (H i) fraction and bHI is the H i bias parameter. We describe observational challenges with the present data set and plans to overcome them.
Editor: Oxford University Press
Idioma: Inglés

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Determination of z ∼ 0.8 neutral hydrogen fluctuations using the 21 cm intensity mapping autocorrelation

Switzer, E. R. ; Masui, K. W. ; Bandura, K. ; Calin, L.-M. ; Chang, T.-C. ; Chen, X.-L. ; Li, Y.-C. ; Liao, Y.-W. ; Natarajan, A. ; Pen, U.-L. ; Peterson, J. B. ; Shaw, J. R. ; Voytek, T. C.

Oxford University Press

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