A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 billion stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall 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.
Sandra Moore Faber is an American astrophysicist known for her research on the evolution of galaxies. She is the University Professor of Astronomy and Astrophysics at the University of California, Santa Cruz, and works at the Lick Observatory. She has made discoveries linking the brightness of galaxies to the speed of stars within them and was the co-discoverer of the Faber–Jackson relation. Faber was also instrumental in designing the Keck telescopes in Hawaii.
Marc Aaronson was an American astronomer.
The Royal Astronomical Society (RAS) is a learned society and charity that encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. Its headquarters are in Burlington House, on Piccadilly in London. The society has over 4,000 members, known as fellows, most of whom are professional researchers or postgraduate students. Around a quarter of Fellows live outside the UK.
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.
Bohdan Paczyński or Bohdan Paczynski was a Polish astronomer notable for his theories and work in the fields of stellar evolution, accretion discs, and gamma ray bursts. He is the recipient of the Eddington Medal (1987), the Henry Draper Medal (1997), the Gold Medal of the Royal Astronomical Society (1999), and the Order of Polonia Restituta (2007).
Vera Florence Cooper Rubin was an American astronomer who pioneered work on galaxy rotation rates. She uncovered the discrepancy between the predicted and observed angular motion of galaxies by studying galactic rotation curves. By identifying the galaxy rotation problem, her work provided evidence for the existence of dark matter. These results were later confirmed over subsequent decades.
Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical models. It is the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments.
Eleanor Margaret Burbidge, FRS (née Peachey; 12 August 1919 – 5 April 2020) was a British-American observational astronomer and astrophysicist. In the 1950s, she was one of the founders of stellar nucleosynthesis and was first author of the influential B2FH paper. During the 1960s and 1970s she worked on galaxy rotation curves and quasars, discovering the most distant astronomical object then known. In the 1980s and 1990s she helped develop and utilise the Faint Object Spectrograph on the Hubble Space Telescope. Burbidge was also well known for her work opposing discrimination against women in astronomy.
Willem de Sitter was a Dutch mathematician, physicist, and astronomer.
Donald Lynden-Bell CBE FRS was a British theoretical astrophysicist. He was the first to determine that galaxies contain supermassive black holes at their centres, and that such black holes power quasars. Lynden-Bell was President of the Royal Astronomical Society (1985–1987) and received numerous awards for his work, including the inaugural Kavli Prize for Astrophysics. He worked at the University of Cambridge for his entire career, where he was the first director of its Institute of Astronomy.
The Jackson-Gwilt Medal is an award that has been issued by the Royal Astronomical Society (RAS) since 1897. The original criteria were for the invention, improvement, or development of astronomical instrumentation or techniques; for achievement in observational astronomy; or for achievement in research into the history of astronomy. In 2017, the history of astronomy category was removed for subsequent awards and was transferred to a new award, the Agnes Mary Clerke Medal.
Eric E. Becklin is an American astrophysicist. The primary focus of Becklin's research is infrared imaging and spectroscopy, including the search for brown dwarfs, the detection of circumstellar dust rings, the dynamics and composition of the center of the Milky Way galaxy, and the nature of luminous infrared galaxies.
The Herschel Medal is awarded by the Royal Astronomical Society (RAS) for "investigations of outstanding merit in observational astrophysics". It is awarded for a single piece of work so that younger scientists can be candidates for the award. It is named after the RAS's first president, William Herschel. The medal was first awarded in 1974. From 1974 to 2004 the Herschel Medal was only awarded every three years. From 2004 the frequency was shortened to two years and from 2012 it will be awarded annually. The medal has been shared twice, in 1977 and 1986. It has been awarded 23 times to a total of 25 people, mostly from the UK.
Catherine Heymans is a British astrophysicist, the Astronomer Royal for Scotland, and a professor at the University of Edinburgh based at the Royal Observatory, Edinburgh.
James Scott Dunlop is a Scottish astronomer and academic. He is Professor of Extragalactic Astronomy at the Institute for Astronomy, an institute within the School of Physics and Astronomy at the University of Edinburgh.
Giovanni Fazio is an American physicist at Center for Astrophysics | Harvard & Smithsonian. He is an astrophysicist who has initiated and participated in multiple observation programs.
Stephen Eales is a professor of astrophysics at Cardiff University, where he is currently head of the Astronomy Group. In 2015, he was awarded the Herschel Medal from the Royal Astronomical Society for outstanding contributions to observational astrophysics. He also writes articles and books about astronomy.
