Jacob Burba
A5015248597- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Radio Wave Propagation Studies
- Electromagnetic Compatibility and Measurements
- Telecommunications and Broadcasting Technologies
- Astronomical Observations and Instrumentation
- Millimeter-Wave Propagation and Modeling
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Soil Moisture and Remote Sensing
- Superconducting and THz Device Technology
- Satellite Communication Systems
- Microwave Engineering and Waveguides
- Stellar, planetary, and galactic studies
- Speech and Audio Processing
- Direction-of-Arrival Estimation Techniques
- Optical measurement and interference techniques
- Calibration and Measurement Techniques
- Pulsed Power Technology Applications
- Advanced Wireless Communication Techniques
- Control Systems and Identification
- Adaptive optics and wavefront sensing
University of Manchester
2023-2025
Winona State University
2024
Brown University
2017-2023
John Brown University
2021
Arizona State University
2016
Abstract We report upper limits on the Epoch of Reionization 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights data (∼36 hr integration) from Phase I Hydrogen Array (HERA). The show evidence for systematics that can be largely suppressed systematic models down to a dynamic range ∼10 9 respect peak foreground power. This yields 95% confidence limit <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi...
Abstract Recently, the Hydrogen Epoch of Reionization Array (HERA) has produced experiment’s first upper limits on power spectrum 21 cm fluctuations at z ∼ 8 and 10. Here, we use several independent theoretical models to infer constraints intergalactic medium (IGM) galaxies during epoch reionization from these limits. We find that IGM must have been heated above adiabatic-cooling threshold by 8, uncertainties about ionization radio background. Combining HERA with complementary observations...
Abstract We report the most sensitive upper limits to date on 21 cm epoch of reionization power spectrum using 94 nights observing with Phase I Hydrogen Epoch Reionization Array (HERA). Using similar analysis techniques as in previously reported limits, we find at 95% confidence that Δ 2 ( k = 0.34 h Mpc −1 ) ≤ 457 mK z 7.9 and 0.36 3496 10.4, an improvement by a factor 2.1 2.6, respectively. These are mostly consistent thermal noise over wide range after our data quality cuts, despite...
Abstract This paper presents the design and deployment of Hydrogen Epoch Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements Reionization. First results from I array are published early 2022, system nearing completion. We describe discuss progress on commissioning future upgrades. As designated Square Kilometre pathfinder instrument, we also show number “case studies” that investigate systematics seen while system, which...
We present a study of internal reflection and cross coupling systematics in Phase I the Hydrogen Epoch Reionization Array (HERA). In companion paper, we outlined mathematical formalism for such presented algorithms modeling removing them from data. this work, apply these techniques to data HERA's first observing season as method demonstration. The show evidence that, without removal, would hinder detection 21 cm power spectrum targeted EoR line-of-sight modes range 0.2 < k_parallel 0.5\ h^-1...
ABSTRACT In 21-cm cosmology, precision calibration is key to the separation of neutral hydrogen signal from very bright but spectrally smooth astrophysical foregrounds. The Hydrogen Epoch Reionization Array (HERA), an interferometer specialized for cosmology and now under construction in South Africa, was designed be largely calibrated using self-consistency repeated measurements same interferometric modes. This technique, known as redundant-baseline resolves most internal degrees freedom...
Abstract We discuss absolute calibration strategies for Phase I of the Hydrogen Epoch Reionization Array (HERA), which aims to measure cosmological 21 cm signal from Reionization. HERA is a drift-scan array with 10° wide field view, meaning bright, well-characterized point-source transits are scarce. This, combined HERA’s redundant sampling uv plane and modest angular resolution instrument, make traditional sky-based self-calibration techniques difficult implement high dynamic range....
Radio Frequency Interference (RFI) is an ever-present limiting factor among radio telescopes even in the most remote observing locations. When looking to retain maximum amount of sensitivity and reduce contamination for Epoch Reionization studies, identification removal RFI especially important. In addition improved identification, we must also take into account computational efficiency RFI-Identification algorithm as interferometer arrays such Hydrogen Array grow larger number receivers. To...
ABSTRACT The detection of the Epoch Reionization (EoR) delay power spectrum using a ‘foreground avoidance method’ highly depends on instrument chromaticity. systematic effects induced by radio telescope spread foreground signal in domain, which contaminates EoR window theoretically observable. Applied to Hydrogen Array (HERA), this paper combines detailed electromagnetic and electrical simulations order model chromatic instrument, quantify its frequency time responses. In particular,...
We describe the validation of HERA Phase I software pipeline by a series modular tests, building up to an end-to-end simulation. The philosophy this approach is validate and algorithms used in upper limit analysis on wholly synthetic data satisfying assumptions that analysis, not addressing whether actual meet these assumptions. discuss organization approach, specific tests performed, construction simulations. explicitly limitations scope current simulation effort. With mock visibility...
Abstract The precise characterization and mitigation of systematic effects is one the biggest roadblocks impeding detection fluctuations cosmological 21 cm signals. Missing data in radio experiments, often due to frequency interference (RFI), pose a particular challenge power spectrum analysis as this could lead ringing bright foreground modes Fourier space, heavily contaminating Here we show that problem missing becomes even more arduous presence effects. Using realistic numerical...
ABSTRACT Detection of the faint 21 cm line emission from Cosmic Dawn and Epoch Reionization will require not only exquisite control over instrumental calibration systematics to achieve necessary dynamic range observations but also validation analysis techniques demonstrate their statistical properties signal loss characteristics. A key ingredient in achieving this is ability perform high-fidelity simulations kinds data that are produced by large, many-element, radio interferometric arrays...
Abstract Radio interferometers designed to probe the 21 cm signal from Cosmic Dawn and Epoch of Reionization must contend with systematic effects that make it difficult achieve sufficient dynamic range separate foreground emission other effects. For instance, instrument’s chromatic response modulates otherwise spectrally smooth foregrounds, making them model, while a significant fraction data be excised due presence radio-frequency interference, leaving gaps in data. Errors modeling...
ABSTRACT Power spectrum estimators are an important tool in efforts to detect the 21 cm brightness temperature fluctuations from neutral hydrogen at early times. An initial detection will likely be statistical nature, meaning that it not possible make a coherent map of fluctuations; instead, only their variance measured against background noise and residual systematic effects. Optimal quadratic estimator-based methods often apply inverse covariance weighting data. However, inaccurate...
Radio Frequency Interference (RFI) is one of the systematic challenges preventing 21cm interferometric instruments from detecting Epoch Reionization. To mitigate effects RFI on data analysis pipelines, numerous inpaint techniques have been developed to restore corrupted data. We examine qualitative and quantitative errors introduced into visibilities power spectrum due inpainting. perform our simulated as well real Hydrogen Reionization Array (HERA) Phase 1 upper limits. also introduce a...
Multiple instruments are pursuing constraints on dark energy, observing reionization and opening a window the ages through detection characterization of 21 cm hydrogen line for redshifts ranging from ∼1 to 25. These instruments, including CHIME in sub-meter HERA meter bands, wide-field arrays with multiple-degree beams, typically operating transit mode. Accurate knowledge their primary beams is critical separation bright foregrounds desired cosmological signals, but difficult achieve...
Characterizing the epoch of reionization (EoR) at z≳6 via redshifted 21 cm line neutral Hydrogen (H i) is critical to modern astrophysics and cosmology, thus a key science goal many current planned low-frequency radio telescopes. The primary challenge detecting this signal overwhelmingly bright foreground emission these frequencies, placing stringent requirements on knowledge instruments inaccuracies in analyses. Results from experiments have largely been limited not by thermal sensitivity...
Interferometric experiments designed to detect the highly redshifted 21-cm signal from neutral hydrogen are producing increasingly stringent constraints on power spectrum, but some k-modes remain systematics-dominated. Mutual coupling is a major systematic that must be overcome in order signal, and simulations reproduce effects seen data can guide strategies for mitigating mutual coupling. In this paper, we analyse 12 nights of Hydrogen Epoch Reionization Array compare against include...
The 21 cm transition from neutral Hydrogen promises to be the best observational probe of Epoch Reionisation (EoR). This has led construction low-frequency radio interferometric arrays, such as Reionization Array (HERA), aimed at systematically mapping this emission for first time. Precision calibration, however, is a requirement in observations. Due spatial compactness HERA, array prone effects mutual coupling, which inevitably lead non-smooth calibration errors that contaminate data. When...
Combining the visibilities measured by an interferometer to form a cosmological power spectrum is complicated process. In delay-based analysis, mapping between instrumental and space not one-to-one relation. Instead, neighbouring modes contribute at one point, with their respective contributions encoded in window functions. To better understand interferometer, we assess impact of instrument characteristics analysis choices on these Focusing Hydrogen Epoch Reionization Array (HERA) as case...
We present a comprehensive simulation-based study of the BayesEoR code for 21 cm power spectrum recovery when analytically marginalizing over foreground parameters. To account covariance between signal and contaminating emission, jointly constructs models both signals within Bayesian framework. Due to computational constraints, forward model is constructed using restricted field-of-view (FoV) in image domain. When only EoR contaminants are noise foregrounds, we demonstrate that can...
Precise measurements of the 21 cm power spectrum are crucial for understanding physical processes hydrogen reionization. Currently, this probe is being pursued by low-frequency radio interferometer arrays. As these experiments come closer to making a first detection signal, error estimation will play an increasingly important role in setting robust measurements. Using delay approach, we have produced critical examination different ways that one can estimate bars on spectrum. We do through...
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 conceptual computational challenges, their long-term storage archiving is scientifically essential for generating reliable, reproducible results. We present here the real-time processing (RTP) system Hydrogen Epoch Reionization Array (HERA), a radio interferometer endeavoring to provide first detection highly redshifted 21...
This paper presents the design and deployment of Hydrogen Epoch Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements Reionization. First results from I array are published early 2022, system nearing completion. We describe discuss progress on commissioning future upgrades. As designated Square Kilometer (SKA) pathfinder instrument, we also show number "case studies" that investigate systematics seen while system, which may...