Gérard de Vaucouleurs

Gérard Henri de Vaucouleurs (25 April 1918 – 7 October 1995) was a French astronomer.

Gérard de Vaucouleurs
Gérard de Vaucouleurs00
Born
Gérard Henri de Vaucouleurs

25 April 1918
Died7 October 1995 (aged 77)
Nationality France
Alma materLycee Charlemagne (BSc, 1936)[1]
Sorbonne (PhD, 1949)
Known forDe Vaucouleurs' law
Spouse(s)
Antoinette de Vaucouleurs
(m. 1944; her death 1988)
AwardsHenry Norris Russell Lectureship (1988)
Prix Jules Janssen (1988)
Scientific career
FieldsAstronomy
InstitutionsYale University Observatory
Lowell Observatory
Harvard College Observatory
University of Texas at Austin

Life and career

Born in Paris, he had an early interest in amateur astronomy and received his undergraduate degree in 1939 at the Sorbonne in that city. After military service in World War II, he resumed his pursuit of astronomy.

Fluent in English, he spent 1949–51 in England, 1951–57 in Australia, the latter at Mount Stromlo Observatory, 1957–58 at Lowell Observatory in Arizona and 1958–60 at Harvard. In, 1960 he was appointed to the University of Texas at Austin, where he spent the rest of his career. He died of a heart attack in his home in Austin at the age of 77.[2]

His earliest work had concerned the planet Mars and while at Harvard he used telescope observations from 1909 to 1958 to study the areographic coordinates of features on the surface of Mars.[3] His later work focused on the study of galaxies and he co-authored the Third Reference Catalogue of Bright Galaxies with his wife Antoinette (1921-1987), a fellow UT Austin astronomer and lifelong collaborator.[4] His specialty included reanalyzing Hubble and Sandage's galaxy atlas and recomputing the distance measurements utilizing a method of averaging many different kinds of metrics such as luminosity, the diameters of ring galaxies, brightest star clusters, etc., in a method he called "spreading the risks." During the 1950s he promoted the idea that galactic clusters are grouped into superclusters.[2]

The de Vaucouleurs modified Hubble sequence is a widely used variant of the standard Hubble sequence.

De Vaucouleurs was awarded the Henry Norris Russell Lectureship by the American Astronomical Society in 1988. He was awarded the Prix Jules Janssen of the Société astronomique de France (Astronomical Society of France) in the same year. He and his wife and longtime collaborator, Antoinette de Vaucouleurs, together produced 400 research and technical papers, 20 books and 100 articles for laymen.[2]

See also

References

  1. ^ "Gerard Henri de Vaucouleurs (1918 - 1995)". American Astronomical Society. Retrieved 29 June 2017.
  2. ^ a b c Thomas Jr., Robert McG. (October 11, 1995), "Gerard de Vaucouleurs, 77, Galactic Astronomer, Is Dead", The New York Times, retrieved 2012-02-21
  3. ^ de Vaucouleurs, Gerard (1963), "La Physique des Planetes; Communications Presentees au Onzieme Colloque International d'Astrophysique tenu a Liège, les 9, 10 et 11 Juillet 1962.", Liege International Astrophysical Colloquia, 11: 369–385, Bibcode:1963LIACo..11..369D |chapter= ignored (help)
  4. ^ Memoriam to Antoinette de Vaucouleurs from University of Texas Austin

External links

1918 in France

Events from the year 1918 in France.

1918 in science

The year 1918 in science and technology involved some significant events, listed below.

1995 in France

Events from the year 1995 in France.

Antlia Dwarf

The Antlia Dwarf is a dwarf spheroidal/irregular galaxy. It lies about 1.3 Mpc (4.3 million light-years) from Earth in the constellation Antlia. It is the fourth and faintest member of the nearby Antlia Group of galaxies. The galaxy contains stars of all ages, contains significant amounts of gas, and has experienced recent star formation. The Antlia Dwarf is believed to be tidally interacting with the small barred spiral galaxy NGC 3109.

Belogradchik Observatory

The Astronomical Observatory of Belogradchik or Belogradchik Observatory is an astronomical observatory owned and operated by the Institute of Astronomy of the Bulgarian Academy of Sciences. It is located near the town of Belogradchik in northwestern Bulgaria, at the foot of the Western Balkan Mountains. The other observatory operated by the same institute is the Rozhen Observatory.

Davies (crater)

Davies is a crater on Mars located at 46°N 0°E on the fringe of Acidalia Planitia near Arabia Terra. It is approximately 48 km in diameter. The crater's name was formally approved by the IAU in 2006.It was named in honor of Merton Davies (1917-2001), a pioneer in the cartography of planetary bodies. An employee of the RAND Corporation, he assisted NASA in mapping Mars with colleagues Gérard de Vaucouleurs and Harold Masursky and defined the prime meridian of Mars as passing through the crater Airy-0. Davies Crater lies on the prime meridian, appropriate because Davies was responsible for its delineation.

De Vaucouleurs' law

de Vaucouleurs' law, also known as the de Vaucouleurs profile or de Vaucouleurs model, describes how the surface brightness of an elliptical galaxy varies as a function of apparent distance from the center of the galaxy:

By defining Re as the radius of the isophote containing half of the total luminosity, de Vaucouleurs' profile may be expressed as:

or

where Ie is the surface brightness at Re. This can be confirmed by noting

de Vaucouleurs' model is a special case of Sersic's model, with Sersic index n=4. A number of (internal) density profiles that approximately reproduce de Vaucouleurs' law after projection onto the plane of the sky include Jaffe's model and Dehnen's model.

The model is named after Gérard de Vaucouleurs who first formulated it in 1948. Although an empirical model rather than a law of physics, it was so entrenched in astronomy during the 20th century that it was referred to as a "law".

Dorado Group

The Dorado Group is a loose concentration of galaxies containing both spirals and ellipticals. It is generally considered a 'galaxy group' but may approach the size of a 'galaxy cluster'. It lies primarily in the southern constellation Dorado and is one of the richest galaxy groups of the Southern Hemisphere. Gérard de Vaucouleurs was the first to identify it in 1975 as a large complex nebulae II in the Dorado region, designating it as G16.

Galaxy morphological classification

Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence, devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage.

Herschel Medal

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. The medal has been shared twice, in 1977 and 1986. It has been awarded 18 times to a total of 20 people (19 men, one woman), mostly from the UK.

John Reynolds (astronomer)

John Henry Reynolds (1874–1949) was a British astronomer who served as the president of the Royal Astronomical Society between 1935 and 1937 and is known for his work on the classification of stellar bodies. An amateur, he was the son of Alfred John Reynolds, the Lord Mayor of Birmingham, who owned a company which cut nails. In 1899, at age 25, he was elected a Fellow of the Royal Astronomical Society and in 1907, he financed the construction of a 30-inch reflecting telescope in Helwan, Egypt, the first large telescope to study objects in the such southerly skies. He also hand-constructed a 28-inch telescope in Harborne. Images from the Reynolds telescope was later used by Gérard de Vaucouleurs in his system of classifying galaxies; Reynolds also published his own classification for spiral galaxies in 1920. Edwin Hubble frequently corresponded with Reynolds, and some of his findings into the classification of stellar bodies seems at least inspired by his work. The Hubble–Reynolds law, a formula for measuring the surface brightness of elliptical galaxies, is named after them.

Julien Peridier

Julien Péridier (1882 – April 19, 1967) was a French electrical engineer and amateur astronomer. For his work he was made an Officer of the Legion of Honour. In 1933 he founded a private observatory at Le Houga (Gers), France. After his death, his library and instruments were acquired by the McDonald Observatory at the University of Texas for use in teaching astronomy.

The double 8-inch (200 mm) refracting telescope at Le Houga was used extensively for studies of the planets and the teaching of young astronomers.

In 1959 his observatory was part of an observational campaign regarding an occultation of Regulus by Venus. The team of Harvard observers at Le Houga was led by Gérard de Vaucouleurs, who had previously collaborated with Mr. Péridier on studies at the observatory. The success of the 1959 work started a five-year collaboration with NASA on photometry of the Moon and planets using a 12-inch (300 mm) reflector.

He was married to Adrienne Blanc-Péridier, who was an accomplished author of one-act plays, romantic novels, and biographies.

A crater on Mars is named in his honor.

Ken Freeman (astronomer)

Kenneth Charles Freeman (born 27 August 1940) 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, 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.His research interests are in the formation and dynamics of galaxies and globular clusters, and he is particularly interested in the problem of dark matter in galaxies: he was one of the first to point out that spiral galaxies contain a large fraction of dark matter. He regularly visits the Space Telescope Science Institute as Distinguished Visiting Scientist.He is very active in supporting graduate students and has acted as primary supervisor for 59 PhD students and 12 postdocs. Five of his students have won Hubble Fellowships. He is active in international astronomy, as a division past-president of the International Astronomical Union, and serves on visiting committees for several major astronomical institutions around the world. He has been an invited speaker at 154 international conferences since 1969. He has co-authored a book on dark matter.

List of French astronomers

The following are list of French astronomers, astrophysicists and other notable French people who have made contributions to the field of astronomy. They may have won major prizes or awards, developed or invented widely used techniques or technologies within astronomy, or are directors of major observatories or heads of space-based telescope projects.

List of craters on Mars

This is a list of craters on Mars. Impact craters on Mars larger than 1 km exist by the hundreds of thousands, but only about one thousand of them have names. Names are assigned by the International Astronomical Union after petitioning by relevant scientists, and in general, only craters that have a significant research interest are given names. Martian craters are named after famous scientists and science fiction authors, or if less than 60 km in diameter, after towns on Earth. Craters cannot be named for living people, and names for small craters are rarely intended to commemorate a specific town. Latitude and longitude are given as planetographic coordinates with west longitude.

Lucien Rudaux

Lucien Rudaux (1874–1947) was a French artist and astronomer, who created famous paintings of space themes in the 1920s and 1930s.

The Rudaux crater on Mars and the Lucien Rudaux Memorial Award are named in his honor. The asteroid 3574 Rudaux is also named for him.

Supergalactic coordinate system

Supergalactic coordinates are coordinates in a spherical coordinate system which was designed to have its equator aligned with the supergalactic plane, a major structure in the local universe formed by the preferential distribution of nearby galaxy clusters (such as the Virgo cluster, the Great Attractor and the Pisces-Perseus supercluster) towards a (two-dimensional) plane. The supergalactic plane was recognized by Gérard de Vaucouleurs in 1953 from the Shapley-Ames Catalog, although a flattened distribution of nebulae had been noted by William Herschel over 200 years earlier. Vera Rubin had also identified the supergalactic plane in the 1950s, but her data remained unpublished.By convention, supergalactic latitude and supergalactic longitude are usually denoted by SGB and SGL, respectively, by analogy to b and l conventionally used for galactic coordinates. The zero point for supergalactic longitude is defined by the intersection of this plane with the galactic plane.

William Wilson Morgan

William Wilson Morgan (January 3, 1906 – June 21, 1994) was an American astronomer and astrophysicist. The principal theme in Dr. Morgan's work was stellar and galaxy classification. He is also known for helping prove the existence of spiral arms in our galaxy. In addition to his scientific achievements he served as a professor and as astronomy director for University of Chicago, and was the managing editor for George Hale's Astrophysical Journal.

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