Methods of Error Estimation for Delay Power Spectra in $21\,\textrm{cm}$ Cosmology

Tan, Jianrong; Liu, Adrian; Kern, Nicholas S.; Abdurashidova, Zara; Aguirre, James E.; Alexander, Paul; Ali, Zaki S.; Balfour, Yanga; Beardsley, Adam P.; Bernardi, Gianni; Billings, Tashalee S.; Bowman, Judd D.; Bradley, Richard F.; Bull, Philip; Burba, Jacob; Carey, Steven; Carilli, Christopher L.; Cheng, Carina; DeBoer, David R.; Dexter, Matt; Acedo, Eloy de Lera; Dillon, Joshua S.; Ely, John; Ewall-Wice, Aaron; Fagnoni, Nicolas; Fritz, Randall; Furlanetto, Steve R.; Gale-Sides, Kingsley; Glendenning, Brian; Gorthi, Deepthi; Greig, Bradley; Grobbelaar, Jasper; Halday, Ziyaad; Hazelton, Bryna J.; Hewitt, Jacqueline N.; Hickish, Jack; Jacobs, Daniel C.; Julius, Austin; Kerrigan, Joshua; Kittiwisit, Piyanat; Kohn, Saul A.; Kolopanis, Matthew; Lanman, Adam; La Plante, Paul; Lekalake, Telalo; MacMahon, David; Malan, Lourence; Malgas, Cresshim; Maree, Matthys; Martinot, Zachary E.; Matsetela, Eunice; Mesinger, Andrei; Molewa, Mathakane; Morales, Miguel F.; Mosiane, Tshegofalang; Murray, Steven G.; Neben, Abraham R.; Nikolic, Bojan; Nunhokee, Chuneeta D.; Parsons, Aaron R.; Patra, Nipanjana; Pieterse, Samantha; Pober, Jonathan C.; Razavi-Ghods, Nima; Ringuette, Jon; Robnett, James; Rosie, Kathryn; Sims, Peter; Singh, Saurabh; Smith, Craig; Syce, Angelo; Thyagarajan, Nithyanandan; Williams, Peter K. G.; Zheng, Haoxuan

doi:10.48550/arxiv.2103.09941

Cited by 3 publications

(8 citation statements)

References 83 publications

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“…The first check on our power spectra is to ensure that our noise estimates agree with the data at different stages of integration. This has recently been studied and validated for HERA simulations and real data (Kern et al 2020b;Tan et al 2021), but we repeat the exercise here for completeness. Fig.…”

Section: Power Spectrum Recoverymentioning

confidence: 97%

“…(In some cases it was not possible to completely simulate what was done in HC20 and we have noted this.) Our key metric for this validation is the recovery of a known power spectrum, without significant bias in the recovered signal, at the level of error bars that are consistent with the known level of thermal noise and its coupling to the signal, following the error analysis in Tan et al (2021).…”

Section: Overview Of Validation Effortmentioning

confidence: 99%

“…We then calculate two sets of errorbars: a theoretical noise RMS given the measured system temperature (P N ), and a semi-empirical errorbar that accounts for the signal-and-noise cross terms in the power spectrum, PSN (cf. Table 3 of Tan et al 2021). All incoherent averaging (i.e.…”

Section: Power Spectrum Recoverymentioning

confidence: 99%

“…averaging after forming the power spectra) is weighted inversely by P 2 N , but the final quoted errorbars come from PSN . The justification for using these errorbars is outlined in the discussion (Section 5) of Tan et al (2021). HC20 outline three broad LST ranges (or "fields") that are used for forming an averaged power spectrum.…”

Section: Power Spectrum Recoverymentioning

confidence: 99%

See 3 more Smart Citations

Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

Aguirre,

Murray,

Pascua

et al. 2021

Preprint

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Section: Power Spectrum Recoverymentioning

confidence: 97%

Section: Overview Of Validation Effortmentioning

confidence: 99%

Section: Power Spectrum Recoverymentioning

confidence: 99%

Section: Power Spectrum Recoverymentioning

confidence: 99%

See 2 more Smart Citations

Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

Aguirre,

Murray,

Pascua

et al. 2021

Preprint

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“…The results presented by [89] also benefited from a detailed quantification of the uncertainty on the measured power spectrum. [94] provides an overview of the different error-bar methodologies explored by HERA, examining the strengths and weaknesses of various analytic and empirical methods. The chosen methodology for reporting upper limits in [89] is able to both robustly estimate the thermal noise floor of the data, and can also account for boosted noise fluctuations sourced by residual systematic cross terms.…”

Section: Improvedmentioning

confidence: 99%

SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks

Barry¹,

Bernardi²,

Greig³

et al. 2021

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The Square Kilometre Array (SKA) is a planned radio interferometer of unprecedented scale that will revolutionize low-frequency radio astronomy when completed. In particular, one of its core science drivers is the systematic mapping of the Cosmic Dawn and Epoch of Reionization, which mark the birth of the first stars and galaxies in the Universe and their subsequent ionization of primordial intergalactic hydrogen, respectively. The SKA will offer the most sensitive view of these poorly understood epochs using the redshifted 21 cm hyperfine signal from intergalactic hydrogen. However, significant technical challenges stand in the way of realizing this scientific promise. These mainly involve the mitigation of systematics coming from astrophysical foregrounds, terrestrial radio interference, and the instrumental response. The Low Frequency Array, the Murchison Widefield Array and the Hydrogen Epoch of Reionization Array are SKA pathfinder experiments that have developed a variety of strategies for addressing these challenges, each with unique characteristics that stem largely from their different instrumental designs. We outline these various directions, highlighting key differences and synergies, and discuss how these relate to the future of lowfrequency intensity mapping with the SKA. We also briefly summarize the challenges associated with modeling the 21 cm signal and discuss the methodologies being proposed for inferring constraints on astrophysical models.

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HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization

Abdurashidova,

Aguirre,

Alexander

et al. 2021

Preprint

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The HERA Collaboration Recently, the Hydrogen Epoch of Reionization Array (HERA) collaboration has produced the experiment's first upper limits on the power spectrum of 21-cm fluctuations in the early Universe, with measurements at z ∼ 8 and 10. Here, we use several independent theoretical models to infer constraints on the intergalactic medium (IGM) and galaxies during the epoch of reionization (EoR) from these limits. The new constraints require the IGM to have been heated above the adiabatic cooling threshold by z ∼ 8, independent of uncertainties about the IGM ionization state and the nature of the radio background. Combining HERA limits with galaxy and EoR observations constrains the spin temperature of the z ∼ 8 neutral IGM to 27 K < T S < 630 K (2.3 K < T S < 640 K) at 68% (95%) confidence. They therefore also place limits on previously unconstrained aspects of early galaxies, limiting models with low X-ray heating, especially in the presence of strong radio emission. For example, if the z ∼ 8 radio background is dominated by the CMB, the new HERA limits imply that the first galaxies were more efficient in producing X-rays than local ones (with soft band X-ray luminosities per star formation rate constrained to L X /SFR = {10 40.2 , 10 41.9 } erg s −1 M −1 yr at 68% confidence), consistent with expectations of X-ray binaries in low-metallicity environments. The z ∼ 10 limits require even earlier heating if dark-matter interactions (e.g., through millicharges) cool down the hydrogen gas. Using a model in which an extra radio background is produced by galaxies, we rule out (at 95% confidence) the combination of high radio and low X-ray luminosities of L r,ν /SFR> 3.9 × 10 24 W Hz −1 M −1 yr and L X /SFR< 10 40 erg s −1 M −1 yr. The new HERA upper limits neither support nor disfavor a cosmological interpretation of the recent EDGES detection. The analysis framework described here provides a foundation for the interpretation of future HERA results.

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Methods of Error Estimation for Delay Power Spectra in $21\,\textrm{cm}$ Cosmology

Cited by 3 publications

References 83 publications

Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline

SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks

HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization

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