In astronomy, dark matter is a hypothetical form of matter that appears not to interact with light or the electromagnetic field. Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be seen. Such effects occur in the context of formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background anisotropies.
Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy.
Astronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–what they are, rather than where they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.
Richard Salisbury Ellis is Professor of Astrophysics at the University College London. He previously served as the Steele Professor of Astronomy at the California Institute of Technology (Caltech). He was awarded the 2011 Gold Medal of the Royal Astronomical Society, in 2022 the Royal Medal of the Royal Society and in 2023 the Gruber Prize in Cosmology.
Astroparticle physics, also called particle astrophysics, is a branch of particle physics that studies elementary particles of astronomical origin and their relation to astrophysics and cosmology. It is a relatively new field of research emerging at the intersection of particle physics, astronomy, astrophysics, detector physics, relativity, solid state physics, and cosmology. Partly motivated by the discovery of neutrino oscillation, the field has undergone rapid development, both theoretically and experimentally, since the early 2000s.
Lauro Moscardini is an Italian astrophysicist and cosmologist. Moscardini has studied N-body cosmological simulations with non-Gaussian initial conditions. The research activity is mainly focussed in the field of theoretical and observational cosmology, in particular with the application of numerical techniques in astrophysics and the study of the formation of large cosmic structures. Moscardini's research is a mixture of observations and building models of large scale structures in the universe.
Kenneth Charles Freeman is an Australian astronomer and astrophysicist who is currently Duffield Professor of Astronomy in the Research School of Astronomy and Astrophysics at the Mount Stromlo Observatory of the Australian National University in Canberra. He was born in Perth, Western Australia in 1940, studied mathematics and physics at the University of Western Australia, and graduated with first class honours in applied mathematics in 1962. He then went to Cambridge University for postgraduate work in theoretical astrophysics with Leon Mestel and Donald Lynden-Bell, and completed his doctorate in 1965. Following a postdoctoral appointment at the University of Texas with Gérard de Vaucouleurs, and a research fellowship at Trinity College, Cambridge, he returned to Australia in 1967 as a Queen Elizabeth Fellow at Mount Stromlo. Apart from a year in the Kapteyn Institute in Groningen in 1976 and some occasional absences overseas, he has been at Mount Stromlo ever since.
George Petros Efstathiou is a British astrophysicist who is Professor of Astrophysics (1909) at the University of Cambridge and was the first Director of the Kavli Institute for Cosmology at the University of Cambridge from 2008 to 2016. He was previously Savilian Professor of Astronomy at the University of Oxford.
The George Darwin Lectureship is an award granted by the Royal Astronomical Society to a 'distinguished and eloquent speaker' on the subject of Astronomy including astrochemistry, astrobiology and astroparticle physics. The award is named after the astronomer George Darwin and has been given annually since 1984. The speaker may be based in the UK or overseas.
Uroš Seljak is a Slovenian cosmologist and a professor of astronomy and physics at University of California, Berkeley. He is particularly well-known for his research in cosmology and approximate Bayesian statistical methods.
Macarthur Astronomical Society is an organisation of amateur astronomers, based in the Macarthur Region of outer South Western Sydney, New South Wales, Australia.
Macarthur Astronomy Forum is a monthly public forum organised by Macarthur Astronomical Society, providing leading national and international professional astronomers with a platform to address the Forum on topics of astronomical interest; also providing members of the Society and the general public with opportunities to learn and ask questions.
ARC Centre of Excellence for All-Sky Astrophysics was a collaboration of international astronomers dedicated to wide field astronomy. It was formally launched on 12 September 2011, at Sydney Observatory and ceased in 2018.
Warrick John Couch is an Australian professional astronomer. He is currently a professor at Swinburne University of Technology in Melbourne. He was previously the Director of Australia's largest optical observatory, the Australian Astronomical Observatory (AAO). He was also the president of the Australian Institute of Physics (2015–2017), and a non-executive director on the Board of the Giant Magellan Telescope Organization. He was a founding non-executive director of Astronomy Australia Limited.
Rachel Lindsey Webster, is an Australian astrophysicist who became the second female professor of physics in Australia. Her main focus areas are extragalactic astronomy and cosmology; she researches black holes and the first stars of the universe. Webster has a doctoral degree from Cambridge University and has held postdoctoral positions at the University of Toronto and University of Melbourne.
Jamie S. Farnes is a British cosmologist, astrophysicist, and radio astronomer based at the University of Oxford. He studies dark energy, dark matter, cosmic magnetic fields, and the large-scale structure of the universe. In 2018, it was announced by Oxford that Farnes may have simultaneously solved both the dark energy and dark matter problems, using a new negative mass dark fluid toy model that "brings balance to the universe".
Linda Siobhan Sparke is a British astronomer known for her research on the structure and dynamics of galaxies. She is a professor emerita of astronomy at the University of Wisconsin–Madison, and Explorers Program Scientist in the NASA Astrophysics Division.
Nathalie Palanque-Delabrouille,, is a French cosmologist. During her career as a researcher in particle physics, she has taken part in several large-scale experiments. Her work has been recognized several times including the Irène Joliot-Curie Prize, the appointment as Knight of the Legion of Honor and her election to the French Academy of Sciences.
