A5057491630- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Advanced Frequency and Time Standards
- Geophysics and Gravity Measurements
- Seismic Waves and Analysis
- GNSS positioning and interference
- Astrophysics and Cosmic Phenomena
- demographic modeling and climate adaptation
- Low-power high-performance VLSI design
- Geophysics and Sensor Technology
- Seismology and Earthquake Studies
- Advancements in Semiconductor Devices and Circuit Design
- Radiation Effects in Electronics
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Inertial Sensor and Navigation
ARC Centre of Excellence for Gravitational Wave Discovery
2020-2025
Australian Research Council
2024-2025
Swinburne University of Technology
2020-2025
Shahid Beheshti University
2015
Abstract We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. is a high-gain ( ${\sim}2.8\,\mbox{K Jy}^{-1}$ ) low-system temperature ${\sim}18\,\mbox{K at }20\,\mbox{cm}$ array that currently operates 580–1 670 MHz can produce tied-array beams suitable observations. This paper presents MeerTime Large Survey Project commissioning with PTUSE. Highlights include...
Abstract We present the third data release from Parkes Pulsar Timing Array (PPTA) project. The contains observations of 32 pulsars obtained using 64-m ‘Murriyang’ radio telescope. span is up to 18 yr with a typical cadence 3 weeks. This formed by combining an updated version our second $\sim$ more recent primarily ultra-wide-bandwidth receiver system that operates between 704 and 4032 MHz. provide calibrated pulse profiles, flux density dynamic spectra, times arrival, initial pulsar timing...
Abstract The observation of neutron stars enables the otherwise impossible study fundamental physical processes. timing binary radio pulsars is particularly powerful, as it precise characterization their (three-dimensional) positions and orbits. PSR J0437–4715 an important millisecond pulsar for array experiments also a primary target Neutron Star Interior Composition Explorer (NICER). main aim NICER mission to constrain star equation state by inferring compactness ( M p / R ) star. Direct...
ABSTRACT The main goal of pulsar timing array experiments is to detect correlated signals such as nanohertz-frequency gravitational waves. Pulsar data collected in dense monitoring campaigns can also be used study the stars themselves, their binary companions, and intervening ionized interstellar medium. Timing observations are extraordinarily sensitive changes path-length between Earth, enabling precise measurements positions, distances velocities, shapes orbits. Here we present a analysis...
We present the first 2.5 years of data from MeerKAT Pulsar Timing Array (MPTA), part MeerTime, a Large Survey Project. The MPTA aims to precisely measure pulse arrival times an ensemble 88 pulsars visible Southern Hemisphere, with goal contributing search, detection and study nanohertz-frequency gravitational waves as International Array. This project makes use telescope, operates typical observing cadence two weeks using L-band receiver that records 856-1712 MHz. provide comprehensive...
MeerTime is a five-year Large Survey Project to time pulsars with MeerKAT, the 64-dish South African precursor Square Kilometre Array. The science goals for programme include timing millisecond (MSPs) high precision (< 1 $\mu$s) study Galactic MSP population and contribute global efforts detect nanohertz gravitational waves International Pulsar Timing Array (IPTA). In order plan remainder of use allocated most efficiently, we have conducted an initial census MeerKAT "L-band" receiver 189...
PSR J0540$-$6919 is the second-most energetic radio pulsar known and resides in Large Magellanic Cloud. Like Crab it observed to emit giant pulses (GPs). We used newly-commissioned PTUSE instrument on MeerKAT telescope search for GPs across three observations. In a total integration time of 5.7 hrs we detected 865 above our 7$\sigma$ threshold. With full polarisation information subset data, estimated Faraday rotation measure, $\rm{RM}=-245.8 \pm 1.0$ rad m$^{-2}$ toward pulsar. The...
ABSTRACT Pulsar timing arrays (PTAs) are ensembles of regularly observed millisecond pulsars timed to high precision. Each pulsar in an array could be affected by a suite noise processes, most which astrophysically motivated. Analysing them carefully can used understand these physical processes. However, the primary purpose experiments is detect signals that common all pulsars, particular associated with stochastic gravitational wave background. To this, it paramount appropriately...
ABSTRACT Precision timing of millisecond pulsars (MSPs) in binary systems enables observers to detect the relativistic Shapiro delay induced by space–time curvature. When favourably aligned, this constraints be placed on component masses and system orientation. Here, we present results campaigns seven MSPs observed with 64-antenna MeerKAT radio telescope that show evidence delay: PSRs J0101−6422, J1101−6424, J1125−6014, J1514−4946, J1614−2230, J1732−5049, J1909−3744. Evidence for was found...
ABSTRACT We have determined positions, proper motions, and parallaxes of 77 millisecond pulsars (MSPs) from ∼3 yr MeerKAT radio telescope observations. Our timing noise analyses enable us to measure 35 significant (12 them for the first time) 69 motions. Eight near ecliptic an accurate motion in longitude only. PSR J0955−6150 has a good upper limit on its very small (&lt;0.4 mas yr−1). used with study MSP velocities. This yields 39 transverse velocities, combined MSPs literature...
Millisecond pulsars (MSPs) in binary systems are precise laboratories for tests of gravity and the physics dense matter. Their orbits can show relativistic effects that provide a measurement neutron star mass included timing array experiments search gravitational waves. Neutron measurements key to eventually solving equation state these be obtained by measure Shapiro delay if orbit is viewed near edge-on. Here we report on noise analysis five MSPs observed with MeerKAT radio telescope: PSRs...
Abstract Millisecond pulsars (MSPs) in binary systems are precise laboratories for tests of gravity and the physics dense matter. Their orbits can show relativistic effects that provide a measurement neutron star mass included timing array experiments search gravitational waves. Neutron measurements key to eventually solving equation state these be obtained by measure Shapiro delay if orbit is viewed near edge-on. Here we report on noise analysis five MSPs observed with MeerKAT radio...
ABSTRACT Pulsar timing arrays search for nanohertz-frequency gravitational waves by regularly observing ensembles of millisecond pulsars over many years to look correlated residuals. Recently the first evidence a stochastic wave background has been presented major arrays, with varying levels significance (${\sim} 2\sigma \!-\! 4\sigma$). In this paper, we present results searches MeerKAT Timing Array. Although limited duration (4.5 yr), ${\sim} 250\,000$ arrival times median error just $3 \,...
ABSTRACT Pulse-to-pulse profile shape variations introduce correlations in pulsar times of arrival across radio frequency measured at the same observational epoch. This leads to a broad-band noise excess radiometer noise, which is termed as pulse jitter noise. The presence limits achievable timing precision and decreases sensitivity data sets signals interest such nanohertz-frequency gravitational waves. Current white models used analyses attempt account for this, assuming complete...
ABSTRACT We present a flux density study of 89 millisecond pulsars (MSPs) regularly monitored as part the MeerKAT Pulsar Timing Array (MPTA) using L-Band receiver with an approximately two week cadence between 2019 and 2022. For each pulsar, we have determined mean densities at epoch in eight ∼97 MHz sub-bands ranging from 944 to 1625 MHz. From these derived their modulation indices, average peak-to-median sub-band, well spectral indices across entire frequency range. find that vast majority...
This paper presents high-performance ternary buffer (STB), minimum (STMin) and maximum (STMax) circuits using carbon nanotube field effect transistors (CNTFETs). Multiple valued logic (MVL) has been introduced to overcome the complexity interconnection problems of binary integrated circuits. In addition, outstanding properties CNTFETs such as possibility adopting desired threshold voltage make them very appropriate for mode MVL design. All are examined in different conditions Synopsys HSPICE...
Pulse-to-pulse profile shape variations introduce correlations in pulsar times of arrival (TOAs) across radio frequency measured at the same observational epoch. This leads to a broadband noise excess radiometer noise, which is termed pulse jitter noise. The presence limits achievable timing precision and decreases sensitivity pulsar-timing data sets signals interest such as nanohertz-frequency gravitational waves. Current white models used analyses attempt account for this, assuming...
We have determined positions, proper motions, and parallaxes of $77$ millisecond pulsars (MSPs) from $\sim3$ years MeerKAT radio telescope observations. Our timing noise analyses enable us to measure $35$ significant ($12$ them for the first time) $69$ motions. Eight near ecliptic an accurate motion in longitude only. PSR~J0955$-$6150 has a good upper limit on its very small ($<$0.4 mas yr$^{-1}$). used with study MSP velocities. This yields $39$ transverse velocities, combined MSPs...
The observation of neutron stars enables the otherwise impossible study fundamental physical processes. Timing binary radio pulsars is particularly powerful, as it precise characterization their (three-dimensional) positions and orbits. PSR J0437$-$4715 an important millisecond pulsar for timing array experiments also a primary target Neutron Star Interior Composition ExploreR (NICER). main aim NICER mission to constrain star equation state by inferring compactness ($M_p/R$) star. Direct...
Precision timing of millisecond pulsars in binary systems enables observers to detect the relativistic Shapiro delay induced by space time curvature. When favourably aligned, this constraints be placed on component masses and system orientation. Here we present results campaigns seven observed with 64-antenna MeerKAT radio telescope that show evidence delay: PSRs~J0101$-$6422, J1101$-$6424, J1125$-$6014, J1514$-$4946, J1614$-$2230, J1732$-$5049, J1909$-$3744. Evidence for was found all...