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

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

doi:10.48550/arxiv.2104.09547

Cited by 2 publications

(3 citation statements)

References 50 publications

(93 reference statements)

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“…The analysis and reduction of these data are discussed in H21 and in several supporting papers in more detail (Kern et al 2020a,b;Dillon et al 2020;Tan et al 2021;Aguirre et al 2021). For the purposes of this work, the important takeaway is that, while nearly the full band is processed in the data reduction pipeline, only two portions of the band are largely free of radio frequency interference (RFI), which sets the redshift ranges studied in this work (Band 2, centered at z = 7.9, and Band 1, centered at z = 10.4).…”

Section: Observational Campaignmentioning

confidence: 99%

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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Section: Observational Campaignmentioning

confidence: 99%

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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“…To further bolster confidence in the power spectrum limits set by [89], an independent validation effort was undertaken to ensure that the HERA Phase I analysis pipeline could recover a known input signal from a realistically corrupted mock HERA data simulation [95]. This effort sought to validate many facets of the analysis pipeline, including the accurate simulation of wide-field foreground and EoR signals, the unbiased recovery of direction-independent gains, the mitigation of baseline-based systematics, and the unbiased estimation of the 21 cm power spectrum.…”

Section: Improvedmentioning

confidence: 99%

“…One of the more tangible outcomes of the validation analysis was the discovery of a ∼ 7% overall bias in the flux scale of the HERA calibration pipeline, which was then corrected. While the validation effort of [95] was ambitious in terms of the number of pipeline components tested, it also laid the framework for increasingly more comprehensive validation efforts that will be applied to future HERA results. Some of the current challenges for HERA data analysis include modeling and mitigating the impact of poorly understood diffuse foregrounds [20,96], mitigating residual antenna-based and baseline-based instrumental systematics, and identifying weak levels of radio frequency interference in the data [39,58].…”

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

Preprint

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

Abstract: We describe the validation of the HERA Phase I software pipeline by a series of modular tests, building up to an end-to-end simulation. The philosophy of this approach is to validate the software and

Cited by 2 publications

References 50 publications

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

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

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

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