New EoR power spectrum limits from MWA Phase II using the delay spectrum method and novel systematic rejection
| Autor: | Matthew Kolopanis, Jonathan C Pober, Daniel C Jacobs, Samantha McGraw |
|---|---|
| Rok vydání: | 2023 |
| Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Space and Planetary Science FOS: Physical sciences Astronomy and Astrophysics Astrophysics - Instrumentation and Methods for Astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 521:5120-5138 |
| ISSN: | 1365-2966 0035-8711 |
| Popis: | We present an analysis of Epoch of Reionization data from Phase II of the Murchison Widefield Array using the \texttt{simpleDS} delay spectrum pipeline. Prior work analyzed the same observations using the FHD/$\varepsilon$ppsilon imaging pipeline, and so the present analysis represents the first time that both principal types of 21 cm cosmology power spectrum estimation approaches have been applied to the same data set. Our limits on the 21 cm power spectrum amplitude span a range in $k$ space of $|k| < 1~h_{100}{\rm Mpc}^{-1}$ with a lowest measurement of $\Delta^2(k) \leq$ $4.58\times10^3$ mK$^2$ at $k = 0.190 h_{100}\rm{Mpc}^{-1}$ and $z = 7.14$. In order to achieve these limits, we need to mitigate a previously unidentified common mode systematic in the data set. If not accounted for, this systematic introduces an overall \emph{negative} bias that can make foreground contaminated measurements appear as stringent, noise-limited constraints on the 21 cm signal amplitude. The identification of this systematic highlights the risk in modeling systematics as positive-definite contributions to the power spectrum and in ``conservatively'' interpreting all measurements as upper limits. Comment: 19 pages, 12 figures, Accepted by MNRAS; Updated to match published version |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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