TY - JOUR
T1 - Overcoming real-world obstacles in 21 cm power spectrum estimation
T2 - A method demonstration and results from early Murchison Widefield Array data
AU - Dillon, Joshua S.
AU - Liu, Adrian
AU - Williams, Christopher L.
AU - Hewitt, Jacqueline N.
AU - Tegmark, Max
AU - Morgan, Edward H.
AU - Levine, Alan M.
AU - Morales, Miguel F.
AU - Tingay, Steven J.
AU - Bernardi, Gianni
AU - Bowman, Judd
AU - Briggs, Frank H.
AU - Cappallo, Roger C.
AU - Emrich, David
AU - Mitchell, Daniel A.
AU - Oberoi, Divya
AU - Prabu, Thiagaraj
AU - Wayth, Randall
AU - Webster, Rachel L.
PY - 2014/1/15
Y1 - 2014/1/15
N2 - We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented universally by interferometric observation. By carefully evaluating various estimators and adapting our techniques for large but incomplete data sets, we develop a robust power spectrum estimation framework that preserves the so-called Epoch of Reionization (EoR) window and keeps track of estimator errors and covariances. We apply our method to observations from the 32-tile prototype of the Murchinson Widefield Array to demonstrate the importance of a judicious analysis technique. Lastly, we apply our method to investigate the dependence of the clean EoR window on frequency - especially the frequency dependence of the so-called "wedge feature - and establish upper limits on the power spectrum from z=6.2 to z=11.7. Our lowest limit is Δ(k)<0.3 Kelvin at 95% confidence at a comoving scale k=0.046 Mpc-1 and z=9.5.
AB - We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented universally by interferometric observation. By carefully evaluating various estimators and adapting our techniques for large but incomplete data sets, we develop a robust power spectrum estimation framework that preserves the so-called Epoch of Reionization (EoR) window and keeps track of estimator errors and covariances. We apply our method to observations from the 32-tile prototype of the Murchinson Widefield Array to demonstrate the importance of a judicious analysis technique. Lastly, we apply our method to investigate the dependence of the clean EoR window on frequency - especially the frequency dependence of the so-called "wedge feature - and establish upper limits on the power spectrum from z=6.2 to z=11.7. Our lowest limit is Δ(k)<0.3 Kelvin at 95% confidence at a comoving scale k=0.046 Mpc-1 and z=9.5.
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U2 - 10.1103/PhysRevD.89.023002
DO - 10.1103/PhysRevD.89.023002
M3 - Article
AN - SCOPUS:84894482365
SN - 1550-7998
VL - 89
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 2
M1 - 023002
ER -