Author
Philip Bull
Other affiliations: University of Oslo, University of the Western Cape, California Institute of Technology ...read more
Bio: Philip Bull is an academic researcher from Queen Mary University of London. The author has contributed to research in topics: Intensity mapping & Redshift. The author has an hindex of 34, co-authored 135 publications receiving 4715 citations. Previous affiliations of Philip Bull include University of Oslo & University of the Western Cape.
Topics: Intensity mapping, Redshift, Dark energy, Cosmology, Reionization
Papers
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University of Oslo1, Heidelberg University2, University of Geneva3, University of Oxford4, University of Barcelona5, Aix-Marseille University6, National Institute of Geophysics and Volcanology7, University of Manchester8, RWTH Aachen University9, King's College London10, Stockholm University11, Imperial College London12, ETH Zurich13, Leiden University14, Durham University15, University of Portsmouth16, Lund University17, Case Western Reserve University18, Universidade Estadual de Londrina19, Federal University of Rio de Janeiro20, University of Stavanger21, University of Szczecin22, University of Pennsylvania23, University of Cambridge24, University of Paris25, University of Lisbon26, Radcliffe Institute for Advanced Study27, Institut d'Astrophysique de Paris28
TL;DR: There is a persistent interest in extending cosmology beyond the standard model, ΛCDM, motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm as mentioned in this paper.
378 citations
TL;DR: There is a persistent interest in extending cosmology beyond the standard model, $\Lambda$CDM as discussed by the authors, motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm.
Abstract: Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, $\Lambda$CDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize the current status of $\Lambda$CDM as a physical theory, and review investigations into possible alternatives along a number of different lines, with a particular focus on highlighting the most promising directions. While the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled.
355 citations
TL;DR: In this paper, the authors present a framework for forecasting cosmological constraints from future neutral hydrogen intensity mapping experiments at low to intermediate redshifts, and establish a simple way of comparing such surveys with optical galaxy redshift surveys.
Abstract: We present a framework for forecasting cosmological constraints from future neutral hydrogen intensity mapping experiments at low to intermediate redshifts. In the process, we establish a simple way of comparing such surveys with optical galaxy redshift surveys. We explore a wide range of experimental configurations and assess how well a number of cosmological observables (the expansion rate, growth rate, and angular diameter distance) and parameters (the densities of dark energy and dark matter, spatial curvature, the dark energy equation of state, etc.) will be measured by an extensive roster of upcoming experiments. A number of potential contaminants and systematic effects are also studied in detail. The overall picture is encouraging?if autocorrelation calibration can be controlled to a sufficient level, Phase I of the Square Kilometre Array should be able to constrain the dark energy equation of state about as well as a DETF Stage IV galaxy redshift survey like Euclid, in roughly the same time frame.
347 citations
TL;DR: A detailed overview of the cosmological surveys that will be carried out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable can be found in this article.
Abstract: We present a detailed overview of the cosmological surveys that will be carried out with Phase 1 of the Square Kilometre Array (SKA1), and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5,000 sqdeg; a wide and deep continuum galaxy and HI intensity mapping survey over 20,000 sqdeg from z = 0.35 - 3; and a deep, high-redshift HI intensity mapping survey over 100 sqdeg from z = 3 - 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to z ~ 3 with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to z = 6. These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical surveys like LSST and Euclid, leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys, and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.
226 citations
University of Cape Town1, University of California, Berkeley2, University of Turin3, University of Western Australia4, University of Toronto5, ETH Zurich6, Imperial College London7, University of Barcelona8, University of Oslo9, Peking University10, University of the Western Cape11, Aix-Marseille University12, University of Portsmouth13, Tel Aviv University14, University of Amsterdam15, University of Sydney16, University of Geneva17, University of Hamburg18, University of Ferrara19, Centre national de la recherche scientifique20, Complutense University of Madrid21, Queen Mary University of London22, California Institute of Technology23, University of Padua24, University of Manchester25, Korea Astronomy and Space Science Institute26, Purple Mountain Observatory27, University of KwaZulu-Natal28, The University of Texas Rio Grande Valley29, Curtin University30, University of Queensland31, University of Zurich32, Uppsala University33, King's College London34, University of Bologna35, University of the Basque Country36, Huazhong University of Science and Technology37, University of Melbourne38, Guangzhou University39
TL;DR: The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope as mentioned in this paper.
Abstract: The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.
223 citations
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