A5016863125- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- SAS software applications and methods
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- GNSS positioning and interference
- Computational Physics and Python Applications
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Superconducting Materials and Applications
- Mechanics and Biomechanics Studies
- Spacecraft and Cryogenic Technologies
- Metabolism, Diabetes, and Cancer
- Adaptive optics and wavefront sensing
- Medical Imaging Techniques and Applications
International Centre for Radio Astronomy Research
2016-2025
Curtin University
2016-2025
Mesothelioma Applied Research Foundation
2022
The Centre for Health (New Zealand)
2022
University of Oxford
2014-2019
Délégation Paris 7
2019
Sorbonne Paris Cité
2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2019
Centre National de la Recherche Scientifique
2019
Université Paris Cité
2019
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in new era multi-messenger astronomy. In this paper, we present event GW170817 and its SSS17a/DLT17ck (IAU label AT2017gfo) 14 Australian telescopes partner observatories as part Australian-based Australian-led research programs. We report early- late-time multi-wavelength observations, including optical imaging spectroscopy,...
The mergers of binary compact objects such as neutron stars and black holes are central interest to several areas astrophysics, including the progenitors gamma-ray bursts (GRBs), sources high-frequency gravitational waves likely production sites for heavy element nucleosynthesis via rapid capture (the r-process). These elements include some great geophysical, biological cultural importance, thorium, iodine gold. Here we present observations exceptionally bright burst GRB 230307A. We show...
X-ray quasi-periodic eruptions (QPEs) are a novel addition to the group of extragalactic transients. With only select number known sources, and many more models published trying explain them, we so far limited in our understanding by small statistics. In this work, report discovery two further galaxies showing QPEs, hereafter named eRO-QPE3 eRO-QPE4, with eROSITA telescope on board Spectrum Roentgen Gamma observatory, followed XMM-Newton , NICER, Swift -XRT, SALT ( z = 0.024 0.044,...
The tidal disruption of a star by supermassive black hole leads to short-lived thermal flare. Despite extensive searches, radio follow-up observations known stellar flares (TDFs) have not yet produced conclusive detection. We present detection variable emission from TDF, which we interpret as originating newly-launched jet. multi-wavelength properties the source natural analogy with accretion state changes mass holes, suggesting all TDFs could be accompanied In rest frame our are an order...
Young male and female Sprague-Dawley rats were given drinking water containing 5 or 50 ppm Pb for 40 days prior to mating. Pregnant females continued on these regimens throughout gestation lactation. After weaning the offspring similarly exposed through adulthood. Reflex development, body weights, locomotor activity measured in offspring. Significant delays noted development of righting reflex at eye opening ppm. No difference was observed startle either dose. Mean weights treatment groups...
The lack of unambiguous detections atomic features in the X-ray spectra ultraluminous sources (ULXs) has proven a hindrance diagnosing nature accretion flow. possible association spectral residuals at soft energies with seen absorption and/or emission and potentially broadened by velocity dispersion could therefore hold key to understanding much about these enigmatic sources. Here we show for first time that such are several appear extremely similar shape, implying common origin. Via simple...
Context. During its all-sky survey, the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board Spectrum-Roentgen-Gamma (SRG) observatory has uncovered a growing number of X-ray transients associated nuclei quiescent galaxies. Benefitting from large field view and excellent sensitivity, eROSITA window into time-domain astrophysics yields valuable sample selected nuclear transients. Multi-wavelength follow-up enables us to gain new insights understanding nature emission...
The ROSAT-selected tidal disruption event (TDE) candidate RX J133157.6-324319.7 (J1331), was detected in 1993 as a bright (0.2-2 keV flux of $(1.0 \pm 0.1) \times 10^{-12}$ erg s$^{-1}$ cm$^{-2}$), ultra-soft ($kT=0.11 0.03$ keV) X-ray flare from quiescent galaxy ($z=0.05189$). During its fifth All-Sky survey (eRASS5) 2022, SRG/eROSITA the repeated flaring J1331, where it had rebrightened to an observed 0.2-2 $(6.0 0.7) 10^{-13}$ cm$^{-2}$, with spectral properties ($kT=0.115 0.007$...
GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves 1.4 and 4.8 GHz with Westerbork Synthesis Radio Telescope (WSRT); we obtained its most accurate position European Very Long Baseline Interferometry Network (EVN). Our flux density measurements are combined all data available radio, optical X-ray frequencies to perform broadband modeling in framework...
Abstract We have found a class of circular radio objects in the Evolutionary Map Universe Pilot Survey, using Australian Square Kilometre Array Pathfinder telescope. The appear images as edge-brightened discs, about one arcmin diameter, that are unlike other previously reported literature. explore several possible mechanisms might cause these objects, but none seems to be compelling explanation.
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 The deaths of massive stars are sometimes accompanied by the launch highly relativistic and collimated jets. If jet is pointed towards Earth, we observe a ‘prompt’ gamma-ray burst due to internal shocks or magnetic reconnection events within jet, followed long-lived broadband synchrotron afterglow as interacts with circumburst material. While there solid observational evidence that emission from multiple contributes signature, detailed studies reverse shock, which travels back into...
ABSTRACT A tidal disruption event (TDE) occurs when a star is destroyed by supermassive black hole. Broad-band radio spectral observations of TDEs trace the emission from any outflows or jets that are ejected vicinity However, detections rare, with <20 published to date, and only 11 multi-epoch broad-band coverage. Here we present detection TDE AT2020vwl our subsequent monitoring campaign outflow was produced, spanning 1.5 yr post-optical flare. We tracked evolution as it expanded...
In this letter, we present the results from subsequent X-ray and UV observations of nuclear transient eRASSt J045650.3−203750 (hereafter, J0456−20). We detected five repeating flares J0456−20, marking it as one most promising partial tidal disruption event ( p TDE) candidates. More importantly, also found rapid changes in recurrence time, T recur , by modelling long-term light curve J0456−20. that first decreased rapidly about 300 days to around 230 days. It continued decrease 190 with an...
Abstract It has been proposed that coherent radio emission could be emitted during or shortly following a gamma-ray burst (GRB). Here we present low-frequency (170–200 MHz) search for pulses associated with long-duration GRBs using the Murchison Widefield Array (MWA). The MWA, its rapid-response system, is capable of performing GRB follow-up observations within approximately 30 s. Our single pulse search, temporal and spectral resolutions 100 μ s 10 kHz, covers dispersion measures up to 5000...
We present optical, near-IR, and radio follow up of sixteen Swift bursts, including our discovery nine afterglows a redshift determination for three. These observations, supplemented by data from the literature, provide an afterglow recovery rate 60% in optical/near-IR, much higher than previous missions (BeppoSAX, HETE-2, INTEGRAL, IPN). The optical/near-IR events are on average 1.7 mag fainter at t=12 hr those missions. X-ray similarly compared to pre-Swift bursts. In limiting factor is...
We present high cadence multi-frequency radio observations of the long Gamma-Ray Burst (GRB) 190829A, which was detected at photon energies above 100 GeV by High Energy Stereoscopic System (H.E.S.S.). Observations with Meer Karoo Array Telescope (MeerKAT, 1.3 GHz), and Arcminute Microkelvin Imager - Large (AMI-LA, 15.5 GHz) began one day post-burst lasted nearly 200 days. used complementary data from Swift X-Ray (XRT), ran to days post-burst. a likely forward shock component both MeerKAT XRT...
Abstract In this paper, we present rapid follow-up observations of the short GRB 201006A, consistent with being a compact binary merger, using LOw Frequency ARray (LOFAR). We have detected candidate 5.6σ, short, coherent radio flash at 144 MHz 76.6 mins post-GRB 3σ duration 38 seconds. This is 27 arcsec offset from location, which has probability co-located ∼0.05% (3.8σ) when accounting for measurement uncertainties. Despite offset, show that finding an unrelated transient within 40 location...
Abstract Observations of Galactic supernova remnants (SNRs) are crucial to understanding explosion mechanisms and their impact on our Galaxy’s evolution. SNRs usually identified by searching for extended, circular structures in all-sky surveys. However, the resolution sensitivity any given survey results selection biases related brightness angular scale a subset total SNR population. As result, we have only 1/3 expected number Galaxy. We used data collected Murchison Widefield Array (MWA)...
Abstract Intermediate-mass black holes (10 2 < M BH 10 5 ⊙ ) are an open question in our understanding of hole evolution and growth. They have long been linked to dense star cluster environments, thanks dynamics, but there a limited number secure detections. We leverage existing X-ray observations from the Chandra Observatory optical catalogs Hubble Space Telescope (HST) as well new radio Karl G. Jansky Very Large Array search for any evidence accreting young massive clusters nearby...
It has been proposed that coherent radio emission could be emitted during or shortly following a gamma-ray burst (GRB). Here we present low-frequency ($170-200$ MHz) search for pulses associated with long-duration GRBs using the Murchison Widefield Array (MWA). The MWA, its rapid-response system, is capable of performing GRB follow-up observations within approximately $30$ seconds. Our single pulse search, temporal and spectral resolutions $100\ \mu$s $10$ kHz, covers dispersion measures up...
Abstract We present the discovery of a second radio flare from tidal disruption event (TDE) AT2020vwl via long-term monitoring observations. Late-time flares TDEs are being discovered more commonly, with many showing emission thousands days after stellar disruption, but mechanism that powers these late-time is uncertain. Here, we spectral observations first and observed TDE AT2020vwl. Through detailed monitoring, find evidence for two distinct outflow ejection episodes or period renewed...
We have detected four flares from UV Ceti at 154 MHz using the Murchison Widefield Array. The flux densities between 10--65 mJy --- a factor of 100 fainter than most in literature these frequencies and are only polarization. circular polarized fractions limited to $>27$% 3$\sigma$ confidence two exhibit polarity reversal. suggest that occur periodically on time scale consistent with rotational period Ceti. During brightest observed flare, we also detect significant linear polarization...