Improved 21 cm Epoch Of Reionization Power Spectrum Measurements with a Hybrid Foreground Subtraction and Avoidance Technique. (arXiv:1801.00460v2 [astro-ph.IM] UPDATED)

Improved 21 cm Epoch Of Reionization Power Spectrum Measurements with a Hybrid Foreground Subtraction and Avoidance Technique. (arXiv:1801.00460v2 [astro-ph.IM] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kerrigan_J/0/1/0/all/0/1">Joshua Kerrigan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pober_J/0/1/0/all/0/1">Jonathan Pober</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ali_Z/0/1/0/all/0/1">Zaki Ali</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_C/0/1/0/all/0/1">Carina Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parsons_A/0/1/0/all/0/1">Aaron Parsons</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aguirre_J/0/1/0/all/0/1">James Aguirre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barry_N/0/1/0/all/0/1">Nichole Barry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bradley_R/0/1/0/all/0/1">Richard Bradley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardi_G/0/1/0/all/0/1">Gianni Bernardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carilli_C/0/1/0/all/0/1">Chris Carilli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DeBoer_D/0/1/0/all/0/1">David DeBoer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dillon_J/0/1/0/all/0/1">Joshua Dillon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jacobs_D/0/1/0/all/0/1">Daniel Jacobs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kohn_S/0/1/0/all/0/1">Saul Kohn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kolopanis_M/0/1/0/all/0/1">Matthew Kolopanis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lanman_A/0/1/0/all/0/1">Adam Lanman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_W/0/1/0/all/0/1">Wenyang Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_A/0/1/0/all/0/1">Adrian Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sullivan_I/0/1/0/all/0/1">Ian Sullivan</a>

Observations of the 21cm Epoch of Reionization (EoR) signal are dominated by
Galactic and extragalactic foregrounds. The need for foreground removal has led
to the development of two main techniques, often referred to as “foreground
avoidance” and “foreground subtraction.” Avoidance is associated with filtering
foregrounds in Fourier space, while subtraction uses an explicit foreground
model that is removed. Using 1088 hours of data from the 64-element PAPER
array, we demonstrate that subtraction of a foreground model prior to
delay-space foreground filtering results in a modest but measurable improvement
of the performance of the filter. This proof-of-concept result shows that
improvement stems from the reduced dynamic range requirements needed for the
foreground filter: subtraction of a foreground model reduces the total
foreground power, so for a fixed dynamic range, the filter can push towards
fainter limits. We also find that the choice of window function used in the
foreground filter can have an appreciable affect on the performance near the
edges of the observing band. We demonstrate these effects using a smaller 3
hour sampling of data from the MWA, and find that the hybrid filtering and
subtraction removal approach provides similar improvements across the band as
seen in the case with PAPER-64.

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