Ruby Byrne
A5061844065- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Radio Wave Propagation Studies
- Astronomy and Astrophysical Research
- Soil Moisture and Remote Sensing
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Advanced Image and Video Retrieval Techniques
- Computational Physics and Python Applications
- Adaptive optics and wavefront sensing
- Advanced Wireless Communication Techniques
- Microwave Engineering and Waveguides
- Astronomical Observations and Instrumentation
- Electromagnetic Compatibility and Measurements
- Millimeter-Wave Propagation and Modeling
- History and Developments in Astronomy
- Superconducting and THz Device Technology
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Statistical Mechanics and Entropy
- Distributed and Parallel Computing Systems
- Geophysics and Gravity Measurements
- Genetic factors in colorectal cancer
- Gyrotron and Vacuum Electronics Research
- Solar and Space Plasma Dynamics
California Institute of Technology
2021-2025
Arizona State University
2024
University of Washington
2018-2023
We compute the spherically-averaged power spectrum from four seasons of data obtained for Epoch Reionisation (EoR) project observed with Murchison Widefield Array (MWA). measure EoR over $k= 0.07-3.0~h$Mpc$^{-1}$ at redshifts $z=6.5-8.7$. The largest aggregation 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement (43~mK)$^2$ = 1.8$\times$10$^3$ mK$^2$ $k$=0.14~$h$Mpc$^{-1}$ and $z=6.5$ (2$\sigma$ thermal noise plus sample variance). Using Real-Time System to...
Measurements of 21 cm Epoch Reionization (EoR) structure are subject to systematics originating from both the analysis and observation conditions. Using 2013 data Murchison Widefield Array (MWA), we show importance mitigating sources contamination. A direct comparison between results Beardsley et al. 2016 our updated demonstrates new precision techniques, lowering by a factor 2.8 in power. We then further lower excising observations contaminated ultra-faint RFI, reducing an additional 3.8...
Abstract The compact configuration of Phase II the Murchison Widefield Array (MWA) consists both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model interferometric calibration. highly hexagonal cores give improved power spectrum sensitivity. In this paper, we present analysis nearly 40 hr data targeting one MWA’s epoch reionization (EoR) fields observed in 2016. We use techniques presented Barry et al. several additional developed for work,...
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...
ABSTRACT Observations in the lowest Murchison Widefield Array (MWA) band between 75 and 100 MHz have potential to constrain distribution of neutral hydrogen intergalactic medium at redshift ∼13–17. Using 15 h MWA data, we analyse systematics this such as radio-frequency interference (RFI), ionospheric wide field effects. By updating position point sources, mitigate direction-independent calibration error due offsets. Our strategy is optimized for frequency bands by reducing number...
Abstract Interferometric arrays seeking to measure the 21 cm signal from epoch of reionization (EOR) must contend with overwhelmingly bright emission foreground sources. Accurate recovery will require precise calibration array, and several new avenues for have been pursued in recent years, including methods using redundancy antenna configuration. The newly upgraded Phase II Murchison Widefield Array (MWA) is first interferometer that has large numbers redundant baselines while retaining good...
Abstract Epoch of Reionisation (EoR) data analysis requires unprecedented levels accuracy in radio interferometer pipelines. We have developed an imaging power spectrum to meet these requirements and generate robust 21 cm EoR measurements. In this work, we build a signal path framework mathematically describe each step the analysis, from reduction Fast Holographic Deconvolution (FHD) package generation ε ppsilon package. particular, focus on distinguishing characteristics FHD/ ppsilon:...
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...
Precise instrument calibration is critical to the success of 21 cm Cosmology experiments. Unmitigated errors in contaminate Epoch Reionization (EoR) signal, precluding a detection. Barry et al. 2016 characterizes one class inherent that emerge from calibrating an incomplete sky model, however it has been unclear if model affect redundant arrays. In this paper, we show vulnerable incompleteness even limit perfect antenna positioning and identical beams. These are at level can overwhelm EoR...
Calibration precision is currently a limiting systematic in 21 cm cosmology experiments. While there are innumerable calibration approaches, most can be categorized as either `sky-based,' relying on an extremely accurate model of astronomical foreground emission, or `redundant,' requiring precisely regular array with near-identical antenna response patterns. Both these classes inflexible to the realities interferometric measurement. In practice, errors model, position offsets, and beam...
Abstract We present deep upper limits from the 2014 Murchison Widefield Array Phase I observing season, with a particular emphasis on identifying spectral fingerprints of extremely faint radio frequency interference (RFI) contamination in 21 cm power spectra (PS). After meticulous RFI excision involving combination SSINS flagger and series PS-based jackknife tests, our lowest limit Epoch Reionization (EoR) PS signal is Δ 2 ≤ 1.61 × 10 4 mK at k = 0.258h Mpc −1 redshift 7.1 using 14.7 hr...
Abstract Line-intensity mapping is a promising probe of the Universe’s large-scale structure. We explore sensitivity DSA-2000, forthcoming array consisting over 2000 dishes, to statistical power spectrum neutral hydrogen’s 21 cm emission line. These measurements would reveal distribution hydrogen throughout near-redshift Universe without necessitating resolving individual sources. The success these relies on instrument’s and resilience systematics. show that DSA-2000 will have needed detect...
We introduce a new pipeline for analyzing and mitigating radio frequency interference (RFI), which we call Sky-Subtracted Incoherent Noise Spectra (SSINS). SSINS is designed to identify remove faint RFI below the single baseline thermal noise by employing frequency-matched detection algorithm on baseline-averaged amplitudes of time-differenced visibilities. demonstrate capabilities using Murchison Widefield Array (MWA) in Western Australia. successfully image aircraft flying over array via...
ABSTRACT We present a broad-band map of polarized diffuse emission at 167–198 MHz developed from data the Murchison Widefield Array (MWA). The is designed to improve visibility simulation and precision calibration for 21 cm Epoch Reionization (EoR) experiments. It covers large swath – 11 000 sq. deg. Southern hemisphere sky in all four Stokes parameters captures on angular scales 1–9°. band-averaged structure pre-dominantly unpolarized but has significant linearly near RA = 0 h. evaluate...
ABSTRACT Current attempts to measure the 21 cm power spectrum of neutral hydrogen during epoch reionization (EoR) are limited by systematics that produce measured upper limits above both thermal noise and expected cosmological signal. These arise from a combination observational, instrumental, analysis effects. In order further understand mitigate these effects, it is instructive explore different aspects existing data sets. One such aspect choice observing field. To date, MWA EoR...
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...
ABSTRACT We quantify the effect of radio frequency interference (RFI) on measurements 21-cm power spectrum during Epoch Reionization (EoR). Specifically, we investigate how structure RFI source emission generates contamination in higher order wave modes, which is much more problematic than smooth-spectrum foreground sources. Using a relatively optimistic EoR model, find that even single dim can overwhelm signal $\sim 10\, {\rm mK}^2$ for modes $0.1 \ \lt k 2 \, h\, Mpc}^{-1}$. If total...
Abstract We apply two methods to estimate the 21-cm bispectrum from data taken within Epoch of Reionisation (EoR) project Murchison Widefield Array (MWA). Using acquired with Phase II compact array allows a direct be undertaken on multiple redundantly spaced triangles antenna tiles, as well an based gridded uv -plane. The and estimators are applied 21 h high-band (167–197 MHz; z = 6.2–7.5) 2016 2017 observing seasons. Analytic predictions for bias variance point-source foregrounds derived....
One of the principal challenges 21 cm cosmology experiments is overcoming calibration error. Established approaches in field require an exquisitely accurate sky model, and low-level model errors introduce that corrupt cosmological signal. We present a novel approach called Delay-Weighted Calibration, or DWCal, enables precise even presence Sky error does not affect all power spectrum modes equally, DWCal fits solutions preferentially from error-free modes. apply this technique to simulated...
Precise instrumental calibration is of crucial importance to 21-cm cosmology experiments. The Murchison Widefield Array's (MWA) Phase II compact configuration offers us opportunities for both redundant and sky-based algorithms; using the two in tandem a potential approach mitigate errors caused by inaccurate sky models. MWA Epoch Reionization (EoR) experiment targets three patches (dubbed EoR0, EoR1, EoR2) with deep observations. Previous work \cite{Li_2018} \cite{Wenyang_2019} studied...
Motivated by the desire for wide-field images with well-defined statistical properties 21cm cosmology, we implement an optimal mapping pipeline that computes a maximum likelihood estimator sky using interferometric measurement equation. We demonstrate this direct data from Hydrogen Epoch of Reionization (HERA) Phase I observations. After validating simulated data, develop figure-of-merit comparing four models at 166MHz bandwidth 100kHz. The HERA agree GLEAM catalogs to <10%. subtracting...
We explore methods for robust estimation of the 21 cm signal from Epoch Reionisation (EoR). A Kernel Density Estimator (KDE) is introduced measuring spatial temperature fluctuation power spectrum EoR. The KDE estimates underlying probability distribution function fluctuations as a scale, and contains different systematic biases errors to typical approach estimating spectrum. Extraction histograms visibilities allows moments analysis be used discriminate foregrounds thermal noise. use...