Publications (125)
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…
Effective bias expansion for circumventing 21 cm foregrounds
Wenzer Qin, Kai-Feng Chen, Katelin Schutz +1
The 21 cm line of neutral hydrogen is a promising probe of the Epoch of Reionization (EoR) but suffers from contamination by spectrally smooth foregrounds, which obscure the large-…
Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]
Hannah Fronenberg, Adrian Liu
Intensity mapping -- the large-scale mapping of selected spectral lines without resolving individual sources -- is quickly emerging as an efficient way to conduct large cosmologica…
Methods of Error Estimation for Delay Power Spectra in Cosmology
Jianrong Tan, Adrian Liu, Nicholas S. Kern +71
Precise measurements of the 21 cm power spectrum are crucial for understanding the physical processes of hydrogen reionization. Currently, this probe is being pursued by low-freque…
Mapmaking for Precision 21 cm Cosmology
Joshua S. Dillon, Max Tegmark, Adrian Liu +6
In order to study the "Cosmic Dawn" and the Epoch of Reionization with 21 cm tomography, we need to statistically separate the cosmological signal from foregrounds known to be orde…
Mapping our Universe in 3D with MITEoR
Haoxuan Zheng, Max Tegmark, Victor Buza +33
Mapping our universe in 3D by imaging the redshifted 21 cm line from neutral hydrogen has the potential to overtake the cosmic microwave background as our most powerful cosmologica…
Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
Nicholas S. Kern, Aaron R. Parsons, Joshua S. Dillon +63
We present a study of internal reflection and cross coupling systematics in Phase I of the Hydrogen Epoch of Reionization Array (HERA). In a companion paper, we outlined the mathem…
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…
Global 21cm signal experiments: A designer's guide
Adrian Liu, Jonathan R. Pritchard, Max Tegmark +1
[Abridged] The spatially averaged global spectrum of the redshifted 21cm line has generated much experimental interest, for it is potentially a direct probe of the Epoch of Reioniz…
Astro2020 Science White Paper: Insights Into the Epoch of Reionization with the Highly-Redshifted 21-cm Line
Steven Furlanetto, Chris L. Carilli, Jordan Mirocha +47
The epoch of reionization, when photons from early galaxies ionized the intergalactic medium about a billion years after the Big Bang, is the last major phase transition in the Uni…
Bayesian estimation of cross-coupling and reflection systematics in 21cm array visibility data
Geoff G. Murphy, Philip Bull, Mario G. Santos +76
Observations with radio arrays that target the 21-cm signal originating from the early Universe suffer from a variety of systematic effects. An important class of these are reflect…
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…
PAPER-64 Constraints On Reionization II: The Temperature Of The z=8.4 Intergalactic Medium
Jonathan C. Pober, Zaki S. Ali, Aaron R. Parsons +24
We present constraints on both the kinetic temperature of the intergalactic medium (IGM) at z=8.4, and on models for heating the IGM at high-redshift with X-ray emission from the f…
Automated Detection of Antenna Malfunctions in Large-N Interferometers: A Case Study with the Hydrogen Epoch of Reionization Array
Dara Storer, Joshua S. Dillon, Daniel C. Jacobs +75
We present a framework for identifying and flagging malfunctioning antennas in large radio interferometers. We outline two distinct categories of metrics designed to detect outlier…
Low-redshift 21cm Cosmology in Canada
Adrian Liu, Simon Foreman, Hamsa Padmanabhan +6
Line-intensity mapping of the 21cm line is a powerful probe of large scale structure at z<6, tracing large-scale structure via neutral hydrogen content that is found within galaxie…
Spherical Harmonic Analyses of Intensity Mapping Power Spectra
Adrian Liu, Yunfan Zhang, Aaron R. Parsons
Intensity mapping is a promising technique for surveying the large scale structure of our Universe from to , using the brightness temperature field of spectral li…
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…
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…
Optimized Beam Sculpting with Generalized Fringe-Rate Filters
Aaron R. Parsons, Adrian Liu, Zaki S. Ali +1
We generalize the technique of fringe-rate filtering, whereby visibilities measured by a radio interferometer are re-weighted according to their temporal variation. As the Earth ro…
What Next-Generation 21 cm Power Spectrum Measurements Can Teach Us About the Epoch of Reionization
Jonathan C. Pober, Adrian Liu, Joshua S. Dillon +12
A number of experiments are currently working towards a measurement of the 21 cm signal from the Epoch of Reionization. Whether or not these experiments deliver a detection of cosm…
Towards Understanding How Machines Can Learn Causal Overhypotheses
Eliza Kosoy, David M. Chan, Adrian Liu +7
Recent work in machine learning and cognitive science has suggested that understanding causal information is essential to the development of intelligence. The extensive literature…
Eliminating the optical depth nuisance from the CMB with 21 cm cosmology
Adrian Liu, Jonathan R. Pritchard, Rupert Allison +3
Amongst standard model parameters that are constrained by cosmic microwave background (CMB) observations, the optical depth stands out as a nuisance parameter. While prov…
CHORD HI-Galaxy Survey Forecasts: Searching for nearby dark galaxies and high redshift giants
Akanksha Bij, Kristine Spekkens, Hans S. Hopkins +6
Population studies of gas-rich galaxies across the full range of Neutral Hydrogen (HI) masses that galaxies are known to exhibit ($10^5 \lesssim M_{\mathrm{HI}} \lesssim 10^{11} M_…
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…
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…
A Real Time Processing System for Big Data in Astronomy: Applications to HERA
Paul La Plante, Peter K. G. Williams, Matthew Kolopanis +72
As current- and next-generation astronomical instruments come online, they will generate an unprecedented deluge of data. Analyzing these data in real time presents unique conceptu…
Astro2020 Science White Paper: First Stars and Black Holes at Cosmic Dawn with Redshifted 21-cm Observations
Jordan Mirocha, Daniel Jacobs, Josh Dillon +39
The "cosmic dawn" refers to the period of the Universe's history when stars and black holes first formed and began heating and ionizing hydrogen in the intergalactic medium (IGM).…
Constraining cosmology and ionization history with combined 21 cm power spectrum and global signal measurements
Adrian Liu, Aaron R. Parsons
Improvements in current instruments and the advent of next-generation instruments will soon push observational 21 cm cosmology into a new era, with high significance measurements o…
Erasing the variable: Empirical foreground discovery for global 21 cm spectrum experiments
Eric R. Switzer, Adrian Liu
Spectral measurements of the 21 cm monopole background have the promise of revealing the bulk energetic properties and ionization state of our universe from z ~ 6-30. Synchrotron f…
Cosmology with the Highly Redshifted 21cm Line
Adrian Liu, James Aguirre, Yacine Ali-Haimoud +47
In addition to being a probe of Cosmic Dawn and Epoch of Reionization astrophysics, the 21cm line at is also a powerful way to constrain cosmology. Its power derives from sev…
A simplified, lossless re-analysis of PAPER-64
Matthew Kolopanis, Daniel C. Jacobs, Carina Cheng +20
We present limits on the 21cm power spectrum from the Epoch of Reionization (EoR) using data from the 64 antenna configuration of the Donald C. Backer Precision Array for Probing t…
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…
Clues from --A null test designed for line intensity mapping cross-correlation studies
Debanjan Sarkar, Ella Iles, Adrian Liu
Estimating the auto power spectrum of cosmological tracers from line-intensity mapping (LIM) data is often limited by instrumental noise, residual foregrounds, and systematics. Cro…
A New Probe of the High-z BAO scale: BAO tomography With CMB LIM-Nulling Convergence
Hannah Fronenberg, Abhishek S. Maniyar, Adrian Liu +1
Standard rulers such as the baryon acoustic oscillation (BAO) scale serve as workhorses for precision tests of cosmology, enabling distance measurements that probe the geometry and…
Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data
Joshua S. Dillon, Adrian Liu, Christopher L. Williams +16
We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented univers…
A galaxy-free phenomenological model for the 21-cm power spectrum during reionization
Jordan Mirocha, Julian B. Muñoz, Steven R. Furlanetto +2
Upper limits from the current generation of interferometers targeting the 21-cm signal from high redshifts have recently begun to rule out physically realistic, though still extrem…
Overview of the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD) Project
The CHORD Collaboration, Kevin Bandura, Leonid Belostotski +49
The Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) is a next-generation wideband radio interferometer currently being constructed and commissioned at the Domini…
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…
Machine Learning and the SKA for Cosmic Dawn and the Epoch of Reionization
Anshuman Acharya, Michele Bianco, Daniela Breitman +18
When operational, the SKA will generate unprecedented amounts of data and provide exquisite sensitivity for 21 cm tomography of Cosmic Dawn (CD) and the Epoch of Reionization (EoR)…
Hydrogen Epoch of Reionization Array (HERA)
David R. DeBoer, Aaron R. Parsons, James E. Aguirre +51
The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization ($z=6…
Identifying Reionization Sources from 21cm Maps using Convolutional Neural Networks
Sultan Hassan, Adrian Liu, Saul Kohn +1
Active Galactic Nuclei (AGN) and star-forming galaxies are leading candidates for being the luminous sources that reionized our Universe. Next-generation 21cm surveys are promising…
HI 21cm Cosmology and the Bi-spectrum: Closure Diagnostics in Massively Redundant Interferometric Arrays
C. L. Carilli, Bojan Nikolic, Nithyanandan Thyagarajan +62
New massively redundant low frequency arrays allow for a novel investigation of closure relations in interferometry. We employ commissioning data from the Hydrogen Epoch of Reioniz…
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…
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…
Multi-redshift limits on the 21cm power spectrum from PAPER
Daniel C. Jacobs, Jonathan C. Pober, Aaron R. Parsons +15
The epoch of reionization power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints…
Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization
Michael Pagano, Jing Liu, Adrian Liu +75
Radio Frequency Interference (RFI) is one of the systematic challenges preventing 21cm interferometric instruments from detecting the Epoch of Reionization. To mitigate the effects…
Research and Development for HI Intensity Mapping
Zeeshan Ahmed, David Alonso, Mustafa A. Amin +51
Development of the hardware, data analysis, and simulation techniques for large compact radio arrays dedicated to mapping the 21 cm line of neutral hydrogen gas has proven to be mo…
Unlocking Sensitivity for Visibility-based Estimators of the 21 cm Reionization Power Spectrum
Yunfan Gerry Zhang, Adrian Liu, Aaron R. Parsons
Radio interferometers designed to measure the cosmological 21 cm power spectrum require high sensitivity. Several modern low-frequency interferometers feature drift-scan antennas p…
Direct Optimal Mapping Image Power Spectrum and its Window Functions
Zhilei Xu, Honggeun Kim, Jacqueline N. Hewitt +79
The key to detecting neutral hydrogen during the epoch of reionization (EoR) is to separate the cosmological signal from the dominating foreground radiation. We developed direct op…
An Alcock-Paczynski Test on Reionization Bubbles for Cosmology
Emilie Thélie, Franco Del Balso, Julian B. Muñoz +1
In this paper, we propose an Alcock-PaczyÅski (AP) test to constrain cosmology using HII bubbles during the Epoch of Reionization. Similarly to cosmic voids, a stack of HII bubble…
A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
Adrian Liu, Max Tegmark
21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizi…
Data Analysis for Precision 21 cm Cosmology
Adrian Liu, J. Richard Shaw
The redshifted 21 cm line is an emerging tool in cosmology, in principle permitting three-dimensional surveys of our Universe that reach unprecedentedly large volumes, previously i…
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…
The Hydrogen Epoch of Reionization Array Dish III: Measuring Chromaticity of Prototype Element with Reflectometry
Nipanjana Patra, Aaron R. Parsons, David R. DeBoer +54
The experimental efforts to detect the redshifted 21 cm signal from the Epoch of Reionization (EoR) are limited predominantly by the chromatic instrumental systematic effect. The d…
How well can we measure and understand foregrounds with 21 cm experiments?
Adrian Liu, Max Tegmark
Before it becomes a sensitive probe of the Epoch of Reionization, the Dark Ages, and fundamental physics, 21 cm tomography must successfully contend with the issue of foreground co…
A statistical framework for recovering intensity mapping autocorrelations from crosscorrelations
Lisa McBride, Adrian Liu
Intensity mapping experiments will soon have surveyed large swathes of the sky, providing information about the underlying matter distribution of the early universe. The resulting…
A Fast Method for Power Spectrum and Foreground Analysis for 21 cm Cosmology
Joshua S. Dillon, Adrian Liu, Max Tegmark
We develop and demonstrate an acceleration of the Liu & Tegmark quadratic estimator formalism for inverse variance foreground subtraction and power spectrum estimation in 21 cm tom…
Line-Intensity Mapping: 2017 Status Report
Ely D. Kovetz, Marco P. Viero, Adam Lidz +45
Following the first two annual intensity mapping workshops at Stanford in March 2016 and Johns Hopkins in June 2017, we report on the recent advances in theory, instrumentation and…
Inflation and Early Dark Energy with a Stage II Hydrogen Intensity Mapping Experiment
Cosmic Visions 21 cm Collaboration, Réza Ansari, Evan J. Arena +29
This white paper envisions a revolutionary post-DESI, post-LSST dark energy program based on intensity mapping of the redshifted 21cm emission line from neutral hydrogen at radio f…
Packed Ultra-wideband Mapping Array (PUMA): Astro2020 RFI Response
Emanuele Castorina, Simon Foreman, Dionysios Karagiannis +13
The Packed Ultra-wideband Mapping Array (PUMA) is a proposed low-resolution transit interferometric radio telescope operating over the frequency range 200 - 1100MHz. Its rich scien…
Snowmass2021 Cosmic Frontier White Paper: 21cm Radiation as a Probe of Physics Across Cosmic Ages
Adrian Liu, Laura Newburgh, Benjamin Saliwanchik +1
The 21cm line refers to a forbidden transition in neutral hydrogen associated with alignment of spins of the proton and electron. It is a very low energy transition that is emitted…
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 Roadmap for Astrophysics and Cosmology with High-Redshift 21 cm Intensity Mapping
The Hydrogen Epoch of Reionization Array, Collaboration, James E. Aguirre +29
In this white paper, we lay out a US roadmap for high-redshift 21 cm cosmology (30 < z < 6) in the 2020s. Beginning with the currently-funded HERA and MWA Phase II projects and adv…
Measuring the Cosmological 21 cm Monopole with an Interferometer
Morgan Presley, Adrian Liu, Aaron Parsons
A measurement of the cosmological 21 cm signal remains a promising but as-of-yet unattained ambition of radio astronomy. A positive detection would provide direct observations of k…
Packed Ultra-wideband Mapping Array (PUMA): A Radio Telescope for Cosmology and Transients
Kevin Bandura, Emanuele Castorina, Liam Connor +23
PUMA is a proposal for an ultra-wideband, low-resolution and transit interferometric radio telescope operating at . Its design is driven by six science goal…
LRP2020: Astrostatistics in Canada
Gwendolyn Eadie, Arash Bahramian, Pauline Barmby +16
(Abridged from Executive Summary) This white paper focuses on the interdisciplinary fields of astrostatistics and astroinformatics, in which modern statistical and computational me…
Beyond the Power Spectrum: A New Framework for Non-Stationary Fields with Applications to Light-Cone Effects in Line Intensity Mapping
Mattéo Blamart, Adrian Liu
Modern cosmological surveys cover extremely large volumes and map fluctuations on scales reaching gigaparsecs. As a result, it is no longer a valid assumption to ignore cosmologica…
Validation of the HERA Phase I Epoch of Reionization 21 cm Power Spectrum Software Pipeline
James E. Aguirre, Steven G. Murray, Robert Pascua +73
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 valida…
The Epoch of Reionization Window: I. Mathematical Formalism
Adrian Liu, Aaron R. Parsons, Cathryn M. Trott
The 21 cm line provides a powerful probe of astrophysics and cosmology at high redshifts, but unlocking the potential of this probe requires the robust mitigation of foreground con…
High-redshift 21cm Cosmology in Canada
Adrian Liu, H. Cynthia Chiang, Abigail Crites +2
In the next few years, the 21cm line will enable direct observations of the Dark Ages, Cosmic Dawn, and Reionization, which represent previously unexplored periods in our cosmic hi…
Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum
Nicholas S. Kern, Joshua S. Dillon, Aaron R. Parsons +69
We discuss absolute calibration strategies for Phase I of the Hydrogen Epoch of Reionization Array (HERA), which aims to measure the cosmological 21 cm signal from the Epoch of Rei…
Tomography of the Cosmic Dawn and Reionization Eras with Multiple Tracers
Tzu-Ching Chang, Angus Beane, Olivier Dore +41
The Cosmic Dawn and Reionization epochs remain a fundamental but challenging frontier of astrophysics and cosmology. We advocate a large-scale, multi-tracer approach to develop a c…
Reionization Models Classifier using 21cm Map Deep Learning
Sultan Hassan, Adrian Liu, Saul Kohn +3
Next-generation 21cm observations will enable imaging of reionization on very large scales. These images will contain more astrophysical and cosmological information than the power…
matvis: A matrix-based visibility simulator for fast forward modelling of many-element 21 cm arrays
Piyanat Kittiwisit, Steven G. Murray, Hugh Garsden +95
Detection of the faint 21 cm line emission from the Cosmic Dawn and Epoch of Reionisation will require not only exquisite control over instrumental calibration and systematics to a…
UV Luminosity Functions from HST and JWST: A Possible Resolution to the High-Redshift Galaxy Abundance Puzzle and Implications for Cosmic Strings
Mattéo Blamart, Adrian Liu, Robert Brandenberger +2
Recent observations of high redshift galaxies by the James Webb Space Telescope suggest the presence of a bright population of galaxies that is more abundant than predicted by most…
A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
Michael Pagano, Peter Sims, Adrian Liu +3
Measurement of the global 21-cm signal during Cosmic Dawn (CD) and the Epoch of Reionization (EoR) is made difficult by bright foreground emission which is 2-5 orders of magnitude…
PAPER-64 Constraints on Reionization: The 21cm Power Spectrum at z=8.4
Zaki S. Ali, Aaron R. Parsons, Haoxuan Zheng +20
In this paper, we report new limits on 21cm emission from cosmic reionization based on a 135-day observing campaign with a 64-element deployment of the Donald C. Backer Precision A…
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…
The HERA-19 Commissioning Array: Direction Dependent Effects
Saul A. Kohn, James E. Aguirre, Paul La Plante +64
Foreground power dominates the measurements of interferometers that seek a statistical detection of highly-redshifted HI emission from the Epoch of Reionization (EoR). The chromati…
New Limits on Polarized Power Spectra at 126 and 164 MHz: Relevance to Epoch of Reionization Measurements
David Moore, James E. Aguirre, Saul Kohn +15
Polarized foreground emission is a potential contaminant of attempts to measure the fluctuation power spectrum of highly redshifted 21 cm HI emission from the epoch of reionization…
Characterizing Signal Loss in the 21 cm Reionization Power Spectrum: A Revised Study of PAPER-64
Carina Cheng, Aaron R. Parsons, Matthew Kolopanis +18
The Epoch of Reionization (EoR) is an uncharted era in our Universe's history during which the birth of the first stars and galaxies led to the ionization of neutral hydrogen in th…
SAGE Celer 2.6 Technical Card
SAGEA Research Team, Basab Jha, Firoj Paudel +8
We introduce SAGE Celer 2.6, the latest in our line of general-purpose Celer models from SAGEA. Celer 2.6 is available in 5B, 10B, and 27B parameter sizes and benefits from extensi…
Deep learning from 21-cm tomography of the Cosmic Dawn and Reionization
Nicolas Gillet, Andrei Mesinger, Bradley Greig +2
The 21-cm power spectrum (PS) has been shown to be a powerful discriminant of reionization and cosmic dawn astrophysical parameters. However, the 21-cm tomographic signal is highly…
Signatures of reionization feedback in the near-infrared background
Jordan Mirocha, Adrian Liu, Paul La Plante
The reionization of the intergalactic medium at redshifts is expected to have a lasting impact on galaxies residing in low-mass dark matter halos. Unable to accrete or…
Correlation Calibration: A Hybrid Calibration Technique for Radio Interferometric Arrays
Robert Pascua, Jonathan Sievers, Adrian Liu
Calibrating out per-antenna signal chain effects is an essential step in analyzing radio interferometric data. For drift-scanning arrays, robustly calibrating the data is especiall…
Astro 2020 Science White Paper: Fundamental Cosmology in the Dark Ages with 21-cm Line Fluctuations
Steven Furlanetto, Judd D. Bowman, Jordan Mirocha +43
The Dark Ages are the period between the last scattering of the cosmic microwave background and the appearance of the first luminous sources, spanning approximately 1100 < z < 30.…
Overview of 21cm Experiments at high redshift with SKAO
CD Science Working Group, Gianni Bernardi, Daniela Breitman +81
We provide an overview of the eight SKAO Science Book chapters that motivate the Epoch of Reionisation and Cosmic Dawn experiments with SKA-Low. We describe the individual SKA-Low…
Constraining Cosmology With the CMB LIM-Nulling Convergence
Hannah Fronenberg, Abhishek S. Maniyar, Anthony R. Pullen +1
Lensing reconstruction maps from the cosmic microwave background (CMB) provide direct observations of the matter distribution of the universe without the use of a biased tracer. Su…
Mapping Cosmic Dawn and Reionization: Challenges and Synergies
Marcelo A. Alvarez, Anastasia Fialkov, Paul La Plante +47
Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored observational eras in cosmology: a time at which the first galaxies and supermassive black holes formed…
The Correlation Calibration of PAPER-64 data
Tamirat G. Gogo, Yin-Zhe Ma, Piyanat Kittiwisit +21
Observation of redshifted 21-cm signal from the Epoch of Reionization (EoR) is challenging due to contamination from the bright foreground sources that exceed the signal by several…
The of Neutral Hydrogen: Increased CMB Optical Depth at Long Wavelengths
Gilbert Holder, Adrian Liu, Tzu-Ching Chang +1
At wavelengths longer than 21 cm, photons from the long-wavelength tail of the cosmic microwave background (CMB) have a non-zero probability of being absorbed by distant neutral hy…
An Improved Model of Diffuse Galactic Radio Emission from 10 MHz to 5 THz
Haoxuan Zheng, Max Tegmark, Joshua S. Dillon +6
We present an improved Global Sky Model (GSM) of diffuse galactic radio emission from 10 MHz to 5 THz, whose uses include foreground modeling for CMB and 21 cm cosmology. Our model…
Pulsar timing can constrain primordial black holes in the LIGO mass window
Katelin Schutz, Adrian Liu
The recent discovery of gravitational waves from merging black holes has generated interest in primordial black holes as a possible component of the dark matter. In this paper, we…
Recovering the Wedge Modes Lost to 21-cm Foregrounds
Samuel Gagnon-Hartman, Yue Cui, Jacob Kennedy +2
One of the critical challenges facing imaging studies of the 21-cm signal at the Epoch of Reionization (EoR) is the separation of astrophysical foreground contamination. These fore…
Improved 21 cm Epoch Of Reionization Power Spectrum Measurements with a Hybrid Foreground Subtraction and Avoidance Technique
Joshua Kerrigan, Jonathan Pober, Zaki Ali +16
Observations of the 21cm Epoch of Reionization (EoR) signal are dominated by Galactic and extragalactic foregrounds. The need for foreground removal has led to the development of t…
Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure
Joshua S. Dillon, Saul A. Kohn, Aaron R. Parsons +8
21 cm cosmology is a promising new probe of the evolution of visible matter in our universe, especially during the poorly-constrained Cosmic Dawn and Epoch of Reionization. However…
Learning Causal Overhypotheses through Exploration in Children and Computational Models
Eliza Kosoy, Adrian Liu, Jasmine Collins +7
Despite recent progress in reinforcement learning (RL), RL algorithms for exploration still remain an active area of research. Existing methods often focus on state-based metrics,…
Systematic uncertainties in models of the cosmic dawn
Jordan Mirocha, Henri Lamarre, Adrian Liu
Models of the reionization and reheating of the intergalactic medium (IGM) at redshifts continue to grow more sophisticated in anticipation of near-future 21-cm, cosm…
Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
Lindsay M. Berkhout, Daniel C. Jacobs, Zuhra Abdurashidova +93
This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission m…
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.…