A5084977040- Radio Astronomy Observations and Technology
- Radio Wave Propagation Studies
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Millimeter-Wave Propagation and Modeling
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- GNSS positioning and interference
- Gyrotron and Vacuum Electronics Research
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- Geophysics and Sensor Technology
University of Groningen
2024
ARC Centre of Excellence for All-sky Astrophysics
2021-2022
ASTRO-3D
2021-2022
International Centre for Radio Astronomy Research
2021-2022
Curtin University
2021-2022
Studying the redshifted 21-cm signal from neutral hydrogen during Epoch of Reionisation and Cosmic Dawn is fundamental for understanding physics early universe. One challenges that experiments face contamination by bright foreground sources, such as Cygnus,A, which accurate spatial spectral models are needed to minimise residual after their removal. In this work, we develop a new, high-resolution model Cygnus,A using Low Frequency Array (LOFAR) observations in 110--250,MHz range, improving...
The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the direction-dependent ionospheric effects, time-varying can cause signal decorrelate. ionosphere's influence over various spatiotemporal scales introduces baseline-dependent effect interferometric array. We study impact decorrelation high-redshift observations with Low Frequency Array (LOFAR). Datasets corruptions...
One of the principal systematic constraints on Epoch Reionisation (EoR) experiment is accuracy foreground calibration model. Recent results have shown that highly accurate models extended sources, and including for sources in both primary beam its sidelobes, are necessary reducing power. To improve source EoR fields observed by Murchison Widefield Array (MWA), we conducted MWA Long Baseline Survey (LoBES). This survey consists multi-frequency observations main their eight neighbouring using...
Abstract The Epoch of Reionisation (EoR) is the period within which neutral universe transitioned to an ionised one. This remains unobserved using low-frequency radio interferometers, target 21 cm signal hydrogen emitted in this era. Murchison Widefield Array (MWA) telescope was built with detection as one its major science goals. One most significant challenges towards a successful that calibration, especially presence Earth’s ionosphere. By introducing refractive source shifts, distorting...
Abstract The redshifted cosmological 21-cm signal emitted by neutral hydrogen during the first billion years of universe is much fainter relative to other galactic and extragalactic radio emissions, posing a great challenge towards detection signal. Therefore, precise instrumental calibration vital prerequisite for success interferometers such as Murchison Widefield Array (MWA), which aim detection. Over previous years, novel techniques targeting power spectrum paradigm EoR science have been...
One of the main obstacles preventing detection redshifted 21-cm signal from neutral hydrogen in early Universe is astrophysical foreground emission, which several orders magnitude brighter than signal. The foregrounds, due to their smooth spectra, are expected predominantly occupy a region cylindrical power spectrum known as wedge. However, conventional equations describing extent wedge derived under flat-sky approximation. This assumption breaks down for tracking wide-field instruments,...
Context. Current radio interferometers output multi-petabyte-scale volumes of data per year, making the storage, transfer, and processing these a sizeable challenge. This challenge is expected to grow with next-generation telescopes such as Square Kilometre Array (SKA), which will produce considerably larger volume than current instruments. Lossy compression interferometric post-correlation can abate this challenge, but any drawbacks from should be well understood in advance. Aims. reduces...
Neutral hydrogen serves as a crucial probe for the Cosmic Dawn and Epoch of Reionization (EoR). Actual observations 21-cm signal often encounter challenges such thermal noise various systematic effects. To overcome these challenges, we simulate SKA-Low-depth images process them with deep learning method. We utilized foreground residuals acquired by LOFAR during actual North Celestial Pole field observations, excess variances calculated via Gaussian regression, signals generated 21cmFAST...
The redshifted cosmological 21 cm signal emitted by neutral hydrogen during the first billion years of universe is much fainter relative to other galactic and extragalactic radio emissions, posing a great challenge towards detection signal. Therefore, precise instrumental calibration vital prerequisite for success interferometers such as Murchison Widefield Array (MWA), which aim detection. Over previous years, novel techniques targeting power spectrum paradigm EoR science have been actively...