2013/04/30 by Joshua S. Dillon, Adrian Liu, Christopher L. Williams +16 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.89.023002
published as Phys. Rev. D 89, 023002 (2014) · 27 pages, 10 figures. Updated to match the accepted Phys. Rev. D version
arxiv created 2014/01/20 · arxiv updated 2014/01/21
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 "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 Delta(k) < 0.3 Kelvin at 95% confidence at a comoving scale k = 0.046 Mpc-1 and z = 9.5.