Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations

Barry, N.; Wilensky, Michael; Trott, Cathryn M.; Pindor, B.; Beardsley, Adam P.; Hazelton, B. J.; Sullivan, M.; Morales, M. F.; Pober, Jonathan C.; Line, J.; Greig, Bradley; Byrne, R.; Lanman, Adam; Li, W.; Jordan, C.; Joseph, R.; McKinley, B.; Rahimi, M.; Yoshiura, Shintaro; Bowman, Judd D.; Gaensler, B. M.; Hewitt, Jacqueline N.; Jacobs, Daniel; Mitchell, D. A.; Shankar, N. Udaya; Sethi, Shiv K.; Subrahmanyan, R.; Tingay, S. J.; Webster, R. L.; Wyithe, J. Stuart B.

doi:10.3847/1538-4357/ab40a8

Cited by 147 publications

(139 citation statements)

References 70 publications

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“…These findings suggest that redundant calibration can continue to play an important role in 21-cm cosmology analysis going forward. While the results from EoR0 suggest that with a good enough sky model for sky-based calibration, redundant calibration becomes ineffective, we note that the limits from Barry et al (2019b), Li et al (2019), and Trott et al (2020) are all still one to two orders of magnitude above any plausible EoR signal models. Therefore, all we can conclude is that the errors that can be mitigated by redundant calibration are not the dominant source of error in those works.…”

Section: Discussionmentioning

confidence: 62%

“…In general, when we do see consistent improvements, they are at levels of ∼10 3 to 10 4 mK 2 . Given the recent measurements of Barry et al (2019b), Li et al (2019), and Trott et al (2020), which use the MWA to achieve lowest limits of 2 < 3.9 × 10 3 mK 2 , 2 < 2.39 × 10 3 mK 2 , and 2 < 1.8 × 10 3 mK 2 , respectively, we can see improvements of this scale can be significant.…”

Section: Comparison Of Power Spectramentioning

confidence: 85%

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The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis

Zhang

Pober

et al. 2020

Publ. Astron. Soc. Aust.

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Precise instrumental calibration is of crucial importance to 21-cm cosmology experiments. The Murchison Widefield Array’s (MWA) Phase II compact configuration offers us opportunities for both redundant calibration and sky-based calibration algorithms; using the two in tandem is a potential approach to mitigate calibration errors caused by inaccurate sky models. The MWA Epoch of Reionization (EoR) experiment targets three patches of the sky (dubbed EoR0, EoR1, and EoR2) with deep observations. Previous work in Li et al. (2018) and (2019) studied the effect of tandem calibration on the EoR0 field and found that it yielded no significant improvement in the power spectrum (PS) over sky-based calibration alone. In this work, we apply similar techniques to the EoR1 field and find a distinct result: the improvements in the PS from tandem calibration are significant. To understand this result, we analyse both the calibration solutions themselves and the effects on the PS over three nights of EoR1 observations. We conclude that the presence of the bright radio galaxy Fornax A in EoR1 degrades the performance of sky-based calibration, which in turn enables redundant calibration to have a larger impact. These results suggest that redundant calibration can indeed mitigate some level of model incompleteness error.

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Section: Discussionmentioning

confidence: 62%

Section: Comparison Of Power Spectramentioning

confidence: 85%

The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis

Zhang

Pober

et al. 2020

Publ. Astron. Soc. Aust.

Self Cite

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“…This work comes after the publication of MWA EoR upper limits from 2013 Phase I EoR0 high-band data (Beardsley et al 2016;Barry et al 2019b) and 2016 Phase II EoR0 high-band data (Li et al 2019). Those works focussed on improved calibration and data analysis strategies to produce excellent results at low redshift.…”

Section: Discussion and Next Stepsmentioning

confidence: 99%

“…• Identification and flagging of low-level RFI in datasets (Wilensky et al 2019), as shown in Barry et al (2019b) to yield improved results;…”

Section: Discussion and Next Stepsmentioning

confidence: 99%

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Deep multiredshift limits on Epoch of Reionization 21 cm power spectra from four seasons of Murchison Widefield Array observations

Trott

Jordan

Midgley³

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We compute the spherically-averaged power spectrum from four seasons of data obtained for the Epoch of Reionisation (EoR) project observed with the Murchison Widefield Array (MWA). We measure the EoR power spectrum over k = 0.07 − 3.0 hMpc −1 at redshifts z = 6.5 − 8.7. The largest aggregation of 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement of (43 mK) 2 = 1.8×10 3 mK 2 at k=0.14 hMpc −1 and z = 6.5 (2σ thermal noise plus sample variance). Using the Real-Time System to calibrate and the CHIPS pipeline to estimate power spectra, we select the best observations from the central five pointings within the 2013-2016 observing seasons, observing three independent fields and in two frequency bands. This yields 13,591 2-minute snapshots (453 hours), based on a quality assurance metric that measures ionospheric activity. We perform another cut to remove poorly-calibrated data, based on power in the foreground-dominated and EoR-dominated regions of the twodimensional power spectrum, reducing the set to 12,569 observations (419 hours). These data are processed in groups of 20 observations, to retain the capacity to identify poor data, and used to analyse the evolution and structure of the data over field, frequency, and data quality. We subsequently choose the cleanest 8,935 observations (298 hours of data) to form integrated power spectra over the different fields, pointings and redshift ranges.

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Probing early Universe through redshifted 21-cm signal: Modeling and observational challenges

et al. 2023

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Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations

Cited by 147 publications

References 70 publications

The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis

The impact of tandem redundant/sky-based calibration in MWA Phase II data analysis

Deep multiredshift limits on Epoch of Reionization 21 cm power spectra from four seasons of Murchison Widefield Array observations

Probing early Universe through redshifted 21-cm signal: Modeling and observational challenges

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