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Inferring Cosmology and Astrophysics from the High-redshift 21cm Signal with SKA-Low
Anshuman Acharya, Satadru Bag, Sabrina Berger +29
The Square Kilometre Array's low frequency telescope (SKA-Low) will enable inference of astrophysical and cosmological parameters from the redshifted 21 cm signal, probing the Cosm…
First Results from HERA Phase II
The HERA Collaboration, Zuhra Abdurashidova, Tyrone Adams +83
We report the first upper limits on the power spectrum of 21-cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Ar…
Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-Point Statistics
Honggeun Kim, Jacqueline N. Hewitt, Nicholas S. Kern +61
Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early universe. We assess the impact of instrumental…
Impacts and Statistical Mitigation of Missing Data on the 21cm Power Spectrum: A Case Study with the Hydrogen Epoch of Reionization Array
Kai-Feng Chen, Michael J. Wilensky, Adrian Liu +66
The precise characterization and mitigation of systematic effects is one of the biggest roadblocks impeding the detection of the fluctuations of cosmological 21cm signals. Missing…
A Generalized Method for Characterizing 21-cm Power Spectrum Signal Loss from Temporal Filtering of Drift-scanning Visibilities
Robert Pascua, Zachary E. Martinot, Adrian Liu +7
A successful detection of the cosmological 21-cm signal from intensity mapping experiments (for example, during the Epoch of Reioinization or Cosmic Dawn) is contingent on the supp…
Investigating Mutual Coupling in the Hydrogen Epoch of Reionization Array and Mitigating its Effects on the 21-cm Power Spectrum
E. Rath, R. Pascua, A. T. Josaitis +78
Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on the 21-cm power spectrum…
A demonstration of the effect of fringe-rate filtering in the Hydrogen Epoch of Reionization Array delay power spectrum pipeline
Hugh Garsden, Philip Bull, Mike Wilensky +94
Radio interferometers targeting the 21cm brightness temperature fluctuations at high redshift are subject to systematic effects that operate over a range of different timescales. T…
The Impact of Beam Variations on Power Spectrum Estimation for 21 cm Cosmology II: Mitigation of Foreground Systematics for HERA
Honggeun Kim, Nicholas S. Kern, Jacqueline N. Hewitt +7
One key challenge in detecting 21 cm cosmological signal at z > 6 is to separate the cosmological signal from foreground emission. This can be studied in a power spectrum space whe…
Search for the Epoch of Reionisation with HERA: Upper Limits on the Closure Phase Delay Power Spectrum
Pascal M. Keller, Bojan Nikolic, Nithyanandan Thyagarajan +80
Radio interferometers aiming to measure the power spectrum of the redshifted 21 cm line during the Epoch of Reionisation (EoR) need to achieve an unprecedented dynamic range to sep…
On the use of temporal filtering for mitigating galactic synchrotron calibration bias in 21 cm reionization observations
Ntsikelelo Charles, Nicholas Kern, Gianni Bernardi +4
Precision antenna calibration is required for mitigating the impact of foreground contamination in 21 cm cosmological radio surveys. One widely studied source of error is the effec…
Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
The HERA Collaboration, Zara Abdurashidova, Tyrone Adams +92
We report the most sensitive upper limits to date on the 21 cm epoch of reionization power spectrum using 94 nights of observing with Phase I of the Hydrogen Epoch of Reionization…
Impact of instrument and data characteristics in the interferometric reconstruction of the 21 cm power spectrum
Adélie Gorce, Samskruthi Ganjam, Adrian Liu +75
Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process. In a delay-based analysis, the mapping between instrumental…
Direct Optimal Mapping for 21cm Cosmology: A Demonstration with the Hydrogen Epoch of Reionization Array
Zhilei Xu, Jacqueline N. Hewitt, Kai-Feng Chen +78
Motivated by the desire for wide-field images with well-defined statistical properties for 21cm cosmology, we implement an optimal mapping pipeline that computes a maximum likeliho…
Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array
N. Charles, G. Bernardi, H. L. Bester +9
The 21~cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation. The main difficulty in measuring the 21 cm signal is the presen…
SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks
Nichole Barry, Gianni Bernardi, Bradley Greig +2
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 o…
First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
The HERA Collaboration, Zara Abdurashidova, James E. Aguirre +74
We report upper-limits on the Epoch of Reionization (EoR) 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data ( hours of integration) from Phase I of the…
HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
The HERA Collaboration, Zara Abdurashidova, James E. Aguirre +81
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 at z~8 and 10.…
Effects of model incompleteness on the drift-scan calibration of radio telescopes
Bharat K. Gehlot, Daniel C. Jacobs, Judd D. Bowman +76
Precision calibration poses challenges to experiments probing the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn and Epoch of Reionization (z~30-6). In both inter…
Gaussian Process Foreground Subtraction and Power Spectrum Estimation for 21 cm Cosmology
Nicholas Kern, Adrian Liu
One of the primary challenges in enabling the scientific potential of 21 cm intensity mapping at the Epoch of Reionization (EoR) is the separation of astrophysical foreground conta…
Detection of Cosmic Structures using the Bispectrum Phase. II. First Results from Application to Cosmic Reionization Using the Hydrogen Epoch of Reionization Array
Nithyanandan Thyagarajan, Chris L. Carilli, Bojan Nikolic +69
Characterizing the epoch of reionization (EoR) at via the redshifted 21 cm line of neutral Hydrogen (HI) is critical to modern astrophysics and cosmology, and thus a k…
Foreground modelling via Gaussian process regression: an application to HERA data
Abhik Ghosh, Florent Mertens, Gianni Bernardi +70
The key challenge in the observation of the redshifted 21-cm signal from cosmic reionization is its separation from the much brighter foreground emission. Such separation relies on…
DAYENU: A Simple Filter of Smooth Foregrounds for Intensity Mapping Power Spectra
Aaron Ewall-Wice, Nicholas Kern, Joshua S. Dillon +14
We introduce DAYENU, a linear, spectral filter for HI intensity mapping that achieves the desirable foreground mitigation and error minimization properties of inverse co-variance w…
Results from EDGES High-Band: II. Constraints on Parameters of Early Galaxies
Raul A. Monsalve, Bradley Greig, Judd D. Bowman +5
We use the sky-average spectrum measured by EDGES High-Band ( MHz) to constrain parameters of early galaxies independent of the absorption feature at ~MHz reported by B…
Emulating Simulations of Cosmic Dawn for 21cm Power Spectrum Constraints on Cosmology, Reionization, and X-ray Heating
Nicholas S. Kern, Adrian Liu, Aaron R. Parsons +2
Current and upcoming radio interferometric experiments are aiming to make a statistical characterization of the high-redshift 21cm fluctuation signal spanning the hydrogen reioniza…