A5052912810- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Antenna Design and Optimization
- Astrophysical Phenomena and Observations
- Radar Systems and Signal Processing
- Advanced SAR Imaging Techniques
- Geophysics and Gravity Measurements
- Advanced Frequency and Time Standards
- Astronomical Observations and Instrumentation
- Particle Accelerators and Free-Electron Lasers
- Soil Moisture and Remote Sensing
- Radio Wave Propagation Studies
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- High-pressure geophysics and materials
- Electromagnetic Compatibility and Measurements
- Stellar, planetary, and galactic studies
- Urban Heat Island Mitigation
- Magnetic Bearings and Levitation Dynamics
- Electric Motor Design and Analysis
- Night-time city culture
Monash Health
2024
International Centre for Radio Astronomy Research
2017-2023
Curtin University
2017-2023
The University of Western Australia
2023
University of Hull
2023
Christopher Newport University
2020-2021
Institute of Radio Astronomy
2021
California State University, Fullerton
2017-2020
Cerro Tololo Inter-American Observatory
2020
Louisiana State University
2014-2018
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 We describe the motivation and design details of ‘Phase II’ upgrade Murchison Widefield Array radio telescope. The expansion doubles to 256 number antenna tiles deployed in array. new enhance capabilities several key science areas. Seventy-two are a regular configuration near existing array core. These surface brightness sensitivity will improve ability estimate slope Epoch Reionisation power spectrum by factor ∼3.5. remaining 56 on long baselines, doubling maximum baseline...
Abstract We describe a new low-frequency wideband radio survey of the southern sky. Observations covering 72–231 MHz and Declinations south $+30^\circ$ have been performed with Murchison Widefield Array “extended” Phase II configuration over 2018–2020 will be processed to form data products including continuum polarisation images mosaics, multi-frequency catalogues, transient search data, ionospheric measurements. From pilot field described in this work, we publish an initial release 1,447...
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 The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low-frequency (80–300 MHz) southern sky. Since beginning operations in mid-2013, MWA has opened a new observational window hemisphere enabling many science areas. driving objectives of original design were observe 21 cm radiation from Epoch Reionisation (EoR), explore radio time domain, perform Galactic and extragalactic surveys, monitor solar, heliospheric, ionospheric phenomena. All together...
Abstract We present an overview of the Southern-sky MWA Rapid Two-metre (SMART) pulsar survey that exploits Murchison Widefield Array’s large field view and voltage-capture system to sky south 30 $^{\circ}$ in declination for pulsars fast transients 140–170 MHz band. The is enabled by advent Phase II MWA’s compact configuration, which offers enormous efficiency beam-forming processing costs, thereby making all-sky this magnitude tractable with MWA. Even long dwell times employed (4800 s),...
We present the results of a coordinated campaign conducted with Murchison Widefield Array (MWA) to shadow Fast Radio Bursts (FRBs) detected by Australian Square Kilometre Pathfinder (ASKAP) at 1.4 GHz, which resulted in simultaneous MWA observations seven ASKAP FRBs. de-dispersed $24$ $\times$ $1.28$ MHz images across $170-200$ band taken 0.5 second time resolution known dispersion measures (DMs) and arrival times bursts searched both within error regions (typically $\sim$ $10$ arcmin...
The design and development process for the Square Kilometre Array (SKA) radio telescope’s Low Frequency Aperture component was progressed during SKA pre-construction phase by an international consortium, with goal of meeting requirements a critical review. As part full-sized prototype ‘station’ deployed – Verification System 1 (AAVS1). We provide system overview describe commissioning results AAVS1, which is low frequency telescope 256 dual-polarisation log-periodic dipole antennas working...
In this paper we demonstrate improved techniques to extend coherent processing intervals for passive radar processing, with the Murchison Widefield Array. Specifically, apply a two stage linear range and Doppler migration compensation by utilising Keystone Formatting recent dechirping method. These methods are used further potential surveillance of space Array using radar, detecting objects orders magnitude smaller than previous work. This also demonstrates how can be extended higher order...
Abstract In Paper I, we presented an overview of the Southern-sky MWA Rapid Two-metre (SMART) survey, including survey design and search pipeline. While combination MWA’s large field-of-view voltage capture system brings a speed ${\sim} 450\, {\textrm{deg}}^{2}\,\textrm{h}^{-1}$ , progression relies on availability compact configuration Phase II array. Over past few years, by taking advantage multiple windows opportunity when was available, have advanced to 75% planned sky coverage. To date,...
We examine data from the Murchison Widefield Array (MWA) in frequency range 72 -- 102 MHz for a field-of-view that serendipitously contained interstellar object 'Oumuamua on 2017 November 28. Observations took place with time resolution of 0.5 s and 10 kHz. %This observation was undertaken another purpose but due to MWA's extremely large field-of-view, observed simultaneously. Based interesting highly unlikely suggestion is an spacecraft, some unusual orbital morphological characteristics,...
We present the Engineering Development Array 2, which is one of two instruments built as a second generation prototype station for future Square Kilometre Low-Frequency Array. The array comprised 256 dual-polarization dipole antennas that can work phased or standalone interferometer. describe design and details changes from previous instruments, well motivation changes. Using an imaging interferometer, we measure sensitivity at five frequencies ranging 70 to 320 MHz.
Recently, low frequency, broadband radio emission has been observed accompanying bright meteors by the Long Wavelength Array (LWA). The spectra between 20 and 60 MHz were captured for several events, while spectral index (dependence of flux density on with $S_\nu \propto \nu^\alpha$) was estimated to be $-4\pm1$ during peak meteor afterglows. Here we present a survey other transient events using Murchison Widefield (MWA) at 72-103 MHz. In our 322-hour survey, down $5\sigma$ detection...
Abstract We provide the first in situ measurements of antenna element beam shapes Murchison Widefield Array. Most current processing pipelines use an assumed shape, which can cause absolute and relative flux density errors polarisation ‘leakage’. Understanding primary is then paramount importance, especially for sensitive experiments such as a measurement 21-cm line from epoch reionisation, where calibration requirements are so extreme that tile to variations may affect our ability make...
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....
We describe the design and performance of Engineering Development Array (EDA), which is a low frequency radio telescope comprising 256 dual-polarisation dipole antennas working as phased-array. The EDA was conceived of, developed, deployed in just 18 months via re-use Square Kilometre (SKA) precursor technology expertise, specifically from Murchison Widefield (MWA) telescope. Using drift scans model for sky brightness temperature at frequencies, we have derived EDA's receiver function...
Rotating Radio Transients (RRATs) represent a relatively new class of pulsar, primarily characterised by their sporadic bursting emission single pulses on time scales minutes to hours. In addition the difficulty involved in detecting these objects, low-frequency ($<$300 MHz) observations RRATs are sparse, which makes understanding broadband properties context normal pulsar population problematic. Here, we present simultaneous detection RRAT J2325-0530 using Murchison Widefield Array (154 and...
Studying the gravitational-wave sky with pulsar timing arrays (PTAs) is a key science goal for Square Kilometre Array (SKA) and its pathfinder telescopes. With current PTAs reaching sub-microsecond precision, making accurate measurements of interstellar propagation effects mitigating them effectively has become increasingly important to realise PTA goals. As these are much stronger at longer wavelengths, low-frequency observations most appealing characterizing medium (ISM) along sight lines...
Abstract We report the independent discovery of PSR J0026-1955 with Murchison Widefield Array (MWA) in ongoing Southern-sky MWA Rapid Two-metre pulsar survey. has a period ∼1.306 s, dispersion measure ∼20.869 pc cm −3 , and nulling fraction ∼77%. This highlights advantages survey's long dwell times (∼80 minutes), which, when fully searched, will be sensitive to expected population similarly bright, intermittent pulsars nulls. A single-pulse analysis MWA's 140–170 MHz band also reveals...
Abstract We describe the design, validation, and commissioning of a new correlator termed ‘MWAX’ for Murchison Widefield Array (MWA) low-frequency radio telescope. MWAX replaces an earlier generation MWA correlator, extending correlation capabilities providing greater flexibility, scalability, maintainability. is designed to exploit current future Phase II/III upgrades infrastructure, most notably simultaneous all 256 MWA’s antenna tiles (and potentially more in future). fully...
Abstract Rare intermittent pulsars pose some of the most challenging questions surrounding pulsar emission mechanism, but typically have relatively minimal low-frequency (≲300 MHz) coverage. We present first detection J1107–5907 with Murchison Widefield Array (MWA) at 154 MHz and simultaneous from recently upgraded Molonglo Observatory Synthesis Telescope (UTMOST) 835 MHz, as part an ongoing observing campaign. During a 30 minute observation, we detected in its bright state for approximately...
Abstract We present a calibration component for the Murchison Widefield Array All-Sky Virtual Observatory (MWA ASVO) utilising newly developed PostgreSQL database of solutions. Since its inauguration in 2013, MWA has recorded over 34 petabytes data archived at Pawsey Supercomputing Centre. According to Data Access policy, become publicly available 18 months after collection. Therefore, most archival are now public. public was provided 2017 via ASVO interface, which allowed researchers...
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...
Abstract One of the major challenges for pulsar timing array (PTA) experiments is mitigation effects turbulent interstellar medium (ISM) from data. These can potentially lead to measurable delays and/or distortions in pulse profiles and scale strongly with inverse radio frequency. Low-frequency observations are therefore highly appealing characterizing them. However, order achieve necessary time resolution resolve profile features short-period millisecond pulsars, phase-coherent dedispersion...