ORCID Profile
0000-0001-7402-3836
Current Organisation
University of Tasmania
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Astronomical and Space Sciences | Cosmology and Extragalactic Astronomy | Stellar Astronomy and Planetary Systems | General Relativity and Gravitational Waves | Galactic Astronomy
ANZSRC Socio-Economic Objective (SEO)
Related Links
Publications
Intermediate homogenization of the Universe and the problem of gravitational entropy
Publisher: American Physical Society (APS)
Date: 25-09-2013
The Taipan Galaxy Survey: Scientific Goals and Observing Strategy
Publisher: Cambridge University Press (CUP)
Date: 2017
DOI: 10.1017/PASA.2017.41
Abstract: The Taipan galaxy survey (hereafter simply ‘Taipan’) is a multi-object spectroscopic survey starting in 2017 that will cover 2π steradians over the southern sky (δ ≲ 10°, | b | ≳ 10°), and obtain optical spectra for about two million galaxies out to z 0.4. Taipan will use the newly refurbished 1.2-m UK Schmidt Telescope at Siding Spring Observatory with the new TAIPAN instrument, which includes an innovative ‘Starbugs’ positioning system capable of rapidly and simultaneously deploying up to 150 spectroscopic fibres (and up to 300 with a proposed upgrade) over the 6° diameter focal plane, and a purpose-built spectrograph operating in the range from 370 to 870 nm with resolving power R ≳ 2000. The main scientific goals of Taipan are (i) to measure the distance scale of the Universe (primarily governed by the local expansion rate, H 0 ) to 1% precision, and the growth rate of structure to 5% (ii) to make the most extensive map yet constructed of the total mass distribution and motions in the local Universe, using peculiar velocities based on improved Fundamental Plane distances, which will enable sensitive tests of gravitational physics and (iii) to deliver a legacy s le of low-redshift galaxies as a unique laboratory for studying galaxy evolution as a function of dark matter halo and stellar mass and environment. The final survey, which will be completed within 5 yrs, will consist of a complete magnitude-limited s le ( i ⩽ 17) of about 1.2 × 10 6 galaxies supplemented by an extension to higher redshifts and fainter magnitudes ( i ⩽ 18.1) of a luminous red galaxy s le of about 0.8 × 10 6 galaxies. Observations and data processing will be carried out remotely and in a fully automated way, using a purpose-built automated ‘virtual observer’ software and an automated data reduction pipeline. The Taipan survey is deliberately designed to maximise its legacy value by complementing and enhancing current and planned surveys of the southern sky at wavelengths from the optical to the radio it will become the primary redshift and optical spectroscopic reference catalogue for the local extragalactic Universe in the southern sky for the coming decade.
Geometry of the quasihyperbolic Szekeres models
Publisher: American Physical Society (APS)
Date: 15-11-2012
Conceptual problems in detecting the evolution of dark energy when using distance measurements
Publisher: EDP Sciences
Date: 30-11-2010
Inhomogeneous cosmological models: exact solutions and their applications
Publisher: IOP Publishing
Date: 02-08-2011
Testing the copernican principle via cosmological observations
Publisher: IOP Publishing
Date: 13-02-2009
The Great Attractor and the Shapley Concentration
Publisher: Springer Science and Business Media LLC
Date: 09-01-2008
Bayesian analysis of the backreaction models
Publisher: American Physical Society (APS)
Date: 12-03-2010
New Test of the Friedmann-Lemaître-Robertson-Walker Metric Using the Distance Sum Rule
Publisher: American Physical Society (APS)
Date: 09-2015
Cosmological backreaction within the Szekeres model and emergence of spatial curvature
Publisher: IOP Publishing
Date: 12-06-2017
Probing spatial homogeneity with LTB models: a detailed discussion
Publisher: EDP Sciences
Date: 10-2014
Cosmological signatures of torsion and how to distinguish torsion from the dark sector
Publisher: American Physical Society (APS)
Date: 27-05-2020
Volume averaging in the quasispherical Szekeres model
Publisher: Springer Science and Business Media LLC
Date: 11-12-2008
Influence of the local Universe on weak gravitational lensing surveys
Publisher: Oxford University Press (OUP)
Date: 03-04-2019
DOI: 10.1093/MNRAS/STZ944
Around the hybrid conference world in the COVID-19 era
Publisher: Springer Science and Business Media LLC
Date: 13-10-2022
Szekeres Swiss-cheese model and supernova observations
Publisher: American Physical Society (APS)
Date: 08-11-2010
Light propagation through large-scale inhomogeneities in the Universe and its impact on cosmological observations
Publisher: EDP Sciences
Date: 2008
DOI: 10.1051/EAS:0830059
Can a charged dust ball be sent through the Reissner-Nordström wormhole?
Publisher: American Physical Society (APS)
Date: 17-12-2007
Apparent horizons in the quasispherical Szekeres models
Publisher: American Physical Society (APS)
Date: 11-06-2012
Antilensing: The Bright Side of Voids
Publisher: American Physical Society (APS)
Date: 10-01-2013
OzDES multi-object fibre spectroscopy for the Dark Energy Survey: results and second data release
Publisher: Oxford University Press (OUP)
Date: 30-05-3202
Abstract: We present a description of the Australian Dark Energy Survey (OzDES) and summarize the results from its 6 years of operations. Using the 2dF fibre positioner and AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope, OzDES has monitored 771 active galactic nuclei, classified hundreds of supernovae, and obtained redshifts for thousands of galaxies that hosted a transient within the 10 deep fields of the Dark Energy Survey. We also present the second OzDES data release, containing the redshifts of almost 30 000 sources, some as faint as rAB = 24 mag, and 375 000 in idual spectra. These data, in combination with the time-series photometry from the Dark Energy Survey, will be used to measure the expansion history of the Universe out to z ∼ 1.2 and the masses of hundreds of black holes out to z ∼ 4. OzDES is a template for future surveys that combine simultaneous monitoring of targets with wide-field imaging cameras and wide-field multi-object spectrographs.
A (giant) void is not mandatory to explain away dark energy with a Lemaître-Tolman model
Publisher: EDP Sciences
Date: 07-2010
Environment dependence of the growth of the most massive objects in the Universe
Publisher: American Physical Society (APS)
Date: 25-06-2019
Structure formation in the quasispherical Szekeres model
Publisher: American Physical Society (APS)
Date: 05-06-2006
Relativistic numerical cosmology with Silent Universes
Publisher: IOP Publishing
Date: 21-12-2017
Differential cosmic expansion and the Hubble flow anisotropy
Publisher: IOP Publishing
Date: 20-06-2016
Ricci focusing, shearing, and the expansion rate in an almost homogeneous Universe
Publisher: IOP Publishing
Date: 03-05-2012
Cosmology with Doppler lensing
Publisher: Oxford University Press (OUP)
Date: 25-07-2014
NONSINGULAR COLLAPSE OF SPHERICALLY SYMMETRIC CHARGED DUST
Publisher: World Scientific Publishing Company
Date: 09-2008
EVOLUTION OF A VOID AND AN ADJACENT GALAXY SUPERCLUSTER IN THE QUASISPHERICAL SZEKERES MODEL
Publisher: World Scientific Publishing Company
Date: 09-2008
Avoidance of singularities in spherically symmetric charged dust
Publisher: American Physical Society (APS)
Date: 22-06-2006
Supernova Ia observations in the Lemaître-Tolman model
Publisher: Springer Science and Business Media LLC
Date: 12-02-2008
Erratum: Avoidance of singularities in spherically symmetric charged dust [Phys. Rev. D73, 124033 (2006)]
Publisher: American Physical Society (APS)
Date: 20-03-2007
Weak lensing and the Dyer-Roeder approximation
Publisher: Oxford University Press (OUP)
Date: 11-01-2011
Inhomogeneous cosmology and backreaction: Current status and future prospects
Publisher: World Scientific Pub Co Pte Lt
Date: 09-02-2017
DOI: 10.1142/S0218271817300117
Abstract: Astronomical observations reveal hierarchical structures in the universe, from galaxies, groups of galaxies, clusters and superclusters, to filaments and voids. On the largest scales, it seems that some kind of statistical homogeneity can be observed. As a result, modern cosmological models are based on spatially homogeneous and isotropic solutions of the Einstein equations, and the evolution of the universe is approximated by the Friedmann equations. In parallel to standard homogeneous cosmology, the field of inhomogeneous cosmology and backreaction is being developed. This field investigates whether small scale inhomogeneities via nonlinear effects can backreact and alter the properties of the universe on its largest scales, leading to a non-Friedmannian evolution. This paper presents the current status of inhomogeneous cosmology and backreaction. It also discusses future prospects of the field of inhomogeneous cosmology, which is based on a survey of 50 academics working in the field of inhomogeneous cosmology.
Imitating accelerated expansion of the Universe by matter inhomogeneities: corrections of some misunderstandings
Publisher: Springer Science and Business Media LLC
Date: 12-06-2010
Cosmic spherical void via coarse-graining and averaging non-spherical structures
Publisher: Elsevier BV
Date: 03-2011
Conditions for spontaneous homogenization of the Universe
Publisher: Springer Science and Business Media LLC
Date: 22-06-2010
Multi-carbohydrase effects on energy utilization depend on soluble non-starch polysaccharides-to-total non-starch polysaccharides in broiler diets
Publisher: Elsevier BV
Date: 02-2021
A full pipeline for modelling low surface brightness galaxies
Publisher: Cambridge University Press (CUP)
Date: 06-2019
DOI: 10.1017/S1743921319008548
Abstract: Cosmological simulations are a powerful tool to test various cosmological and galaxy formation scenarios. The discovery of low surface brightness objects has been a challenge for both of these fields. Our work aims to create a fully reproducible pipeline to generate a realistic dark matter halo catalog with corresponding information on galaxy formation and evolution.
The effect of pressure gradients on luminosity distance-redshift relations
Publisher: IOP Publishing
Date: 15-01-2010
Redshift propagation equations in theβ ′ ≠ 0
Publisher:
American Physical Society (APS)
Date:
04-04-2011
Publisher: American Physical Society (APS)
Date: 04-04-2011
Nonlinear Chaplygin gas cosmologies
Publisher: American Physical Society (APS)
Date: 07-05-2014
The effect of inhomogeneities on the distance to the last scattering surface and the accuracy of the CMB analysis
Publisher: IOP Publishing
Date: 22-02-2011
Imprints of decaying dark matter on cosmic voids
Publisher: American Physical Society (APS)
Date: 17-12-2021
Evolution of cosmic structures in different environments in the quasispherical Szekeres model
Publisher: American Physical Society (APS)
Date: 12-02-2007
Radiation in the process of the formation of voids
Publisher: Oxford University Press (OUP)
Date: 08-2006
A novel approach to the dynamics of Szekeres dust models
Publisher: IOP Publishing
Date: 03-2012
The metric of the cosmos from luminosity and age data
Publisher: IOP Publishing
Date: 06-09-2011
Redshift and distance in the inhomogeneous universe
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4817031
The Szekeres Swiss Cheese model and the CMB observations
Publisher: Springer Science and Business Media LLC
Date: 07-01-2009
The Instantaneous Redshift Difference of Gravitationally Lensed Images: Theory and Observational Prospects
Publisher: American Astronomical Society
Date: 11-2022
Abstract: Due to the expansion of our universe, the redshift of distant objects changes with time. Although the litude of this redshift drift is small, it will be measurable with decade-long c aigns by the next generation of telescopes. Here we present an alternative view of the redshift drift which captures the expansion of the universe in single-epoch observations of the multiple images of gravitationally lensed sources. Considering a sufficiently massive lens, with an associated time delay of order decades, simultaneous photons arriving at a detector would have been emitted decades earlier in one image compared to another, leading to an instantaneous redshift difference between the images. We also investigated the peculiar velocity which may influence the redshift difference in observation. While still requiring the observational power of the next generation of telescopes and instruments, the advantage of such a single-epoch detection over other redshift drift measurements is that it will be less susceptible to systematic effects that result from requiring instrument stability over decade-long c aigns.
Pressure gradients, shell-crossing singularities and acoustic oscillations--application to inhomogeneous cosmological models
Publisher: Oxford University Press (OUP)
Date: 10-2008
Apparent and average accelerations of the Universe
Publisher: IOP Publishing
Date: 03-10-2008
Formation of voids in the Universe within the Lemaître-Tolman model
Publisher: Oxford University Press (OUP)
Date: 09-2005
EXACT INHOMOGENEOUS MODELS AND THE DRIFT OF LIGHT RAYS INDUCED BY NONSYMMETRIC FLOW OF THE COSMIC MEDIUM
Publisher: World Scientific Pub Co Pte Lt
Date: 28-04-2013
DOI: 10.1142/S0218271813300139
Abstract: After introducing the Szekeres and Lemaître–Tolman cosmological models, the real-time cosmology program is briefly mentioned. Then, a few widespread misconceptions about the cosmological models are pointed out and corrected. Investigation of null geodesic equations in the Szekeres models shows that observers in favorable positions would see galaxies drift across the sky at a rate of up to 10 -6 arc s per year. Such a drift would be possible to measure using devices that are under construction the required time of monitoring would be ≈10 years. This effect is zero in the FLRW models, so it provides a measure of inhomogeneity of the Universe. In the Szekeres models, the condition for zero drift is zero shear. But in the shearfree normal models, the condition for zero drift is that, in the comoving coordinates, the time dependence of the metric completely factors out.
CONDITIONS FOR SPONTANEOUS HOMOGENIZATION OF THE UNIVERSE
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2010
DOI: 10.1142/S0218271810018566
Abstract: The present-day universe appears to be homogeneous on very-large scales. Yet when the casual structure of the early universe is considered, it becomes apparent that the early universe must have been highly inhomogeneous. The current paradigm attempts to answer this problem by postulating the inflation mechanism. However, inflation in order to start requires a homogeneous patch of at least the horizon size. This paper examines if dynamical processes of the early universe could lead to homogenization. In the past similar studies seem to imply that the set of initial conditions that leads to homogenization is of measure zero. This essay proves the contrary: a set of initial conditions for spontaneous homogenization of cosmological models can form a set of nonzero measure.
Emerging spatial curvature can resolve the tension between high-redshift CMB and low-redshift distance ladder measurements of the Hubble constant
Publisher: American Physical Society (APS)
Date: 29-05-2018
Gravitational entropy and the cosmological no-hair conjecture
Publisher: American Physical Society (APS)
Date: 23-04-2018
Structures in the Universe by Exact Methods
Publisher: Cambridge University Press
Date: 22-10-2009
Abstract: As the structures in our Universe are mapped out on ever larger scales, and with increasing detail, the use of inhomogeneous models is becoming an essential tool for analyzing and understanding them. This book reviews a number of important developments in the application of inhomogeneous solutions of Einstein's field equations to cosmology. It shows how inhomogeneous models can be employed to study the evolution of structures such as galaxy clusters and galaxies with central black holes, and to account for cosmological observations like supernovae dimming, the cosmic microwave background, baryon acoustic oscillations or the dependence of the Hubble parameter on redshift within classical general relativity. Whatever `dark matter' and `dark energy' turn out to be, inhomogeneities exist on many scales and need to be investigated with all appropriate methods. This book is of great value to all astrophysicists and researchers working in cosmology, from graduate students to academic researchers.
The redshift difference in gravitational lensed systems: a novel probe of cosmology
Publisher: Oxford University Press (OUP)
Date: 17-08-2023
Abstract: The exploration of the redshift drift, a direct measurement of cosmological expansion, is expected to take several decades of observation with stable, sensitive instruments. We introduced a new method to probe cosmology that bypasses the long-period observation by observing the redshift difference, an accumulation of the redshift drift, in multiple-image gravitational lens systems. With this, the photons observed in each image will have traversed through different paths between the source and the observer, and so the lensed images will show different redshifts when observed at the same instance. Here, we consider the impact of the underlying cosmology on the observed redshift difference in gravitational lens systems, generating synthetic data for realistic lens models and exploring the accuracy of determined cosmological parameters. We show that, while the redshift difference is sensitive to the densities of matter and dark energy within a universe, it is independent of the Hubble constant. Finally, we determine the observational considerations for using the redshift difference as a cosmological probe, finding that one thousand lensed sources are enough to make robust determinations of the underlying cosmological parameters. Upcoming cluster lens surveys, such as the Euclid, are expected to detect a sufficient number of such systems.
Related Organisations
Related Funding Activities
ARC Future Fellowships - Grant ID: FT140101270
Start Date: 2015
End Date: 06-2022
Amount: $654,777.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE220100007
Start Date: 07-2024
End Date: 06-2027
Amount: $1,275,295.00
Funder: Australian Research Council
View Funded Activity