Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data
Author(s)
Liu, Adrian Chi-Yan; Hewitt, Jacqueline N.; Morgan, Edward H.; Levine, Alan M.; Morales, Miguel F.; Tingay, Steven J.; Bernardi, G.; Bowman, Judd D.; Briggs, Frank H.; Emrich, David; Mitchell, Daniel A.; Oberoi, Divya; Prabu, Thiagaraj; Wayth, Randall; Webster, Rachel L.; Dillon, Joshua Shane; Williams, Christopher Leigh; Tegmark, Max Erik; Cappallo, Roger J.; ... Show more Show less
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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[superscript −1] and z = 9.5.
Date issued
2014-01Department
Haystack Observatory; Massachusetts Institute of Technology. Department of Physics; MIT Kavli Institute for Astrophysics and Space ResearchJournal
Physical Review D
Publisher
American Physical Society
Citation
Dillon, Joshua S. et al. “Overcoming Real-World Obstacles in 21 Cm Power Spectrum Estimation: A Method Demonstration and Results from Early Murchison Widefield Array Data.” Physical Review D 89.2 (2014): n. pag. © 2014 American Physical Society
Version: Final published version
ISSN
1550-7998
1550-2368