Gerard Henri de Vaucouleurs

Gerard de Vaucouleurs was born on April 25, 1918 in Paris, France. From an early age he was interested in astronomy, observing the moon from the balcony of his family's apartment using a marine telescope he had borrowed. A few years later his mother purchased a telescope for him and he used it to observe various stellar occulations, planetary conjunctions, an eclipse and with his small telescope he photographed close approaches by Mars to the Moon and the Pleiades star cluster.

De Vaucouleurs received a B.Sc. in 1936 from the Lycee Charlemagne in Paris and went to the Sorbonne from 1937-1939 for training in physics, astronomy and physics. Starting in 1939 de Vaucouleurs worked briefly at the private observatory of Julien Peridir, but after two months their association was interrupted by the outbreak of World War II. During the war De Vaucouleurs served as an artillery officer. In 1943 de Vaucouleurs re-enrolled at the Sorbonne to work on his doctoral degree, graduating 1949 after completing a dissertation on the molecular (Rayleigh) scattering of light in gases and liquids. In 1944 he married his first wife Antionette, who was also interested in astronomy.

De Vaucouleurs, interested in extragalactic astronomy did not see a future for himself in France, emigrated first to England where he ran a weekly science radio program for the BBC. The frequently cloudy skies of England led de Vaucouleurs to Australia, where he went to Australian National University in Canberra and in 1951 he got an appointment to the Mt. Stromlo observatory where he became the first research fellow at ANU to preform radial velocity studies of galaxies in the unexplored southern sky. He received a D.Sc. degree from ANU in 1957 for research in molecular physics, optics, photography, astronomy and astrophysics. In 1957 de Vaucouleurs emigrated to the United States where he took a position working at the Lowell Observatory, continuing his observations of galaxies and Mars. In 1958 he moved to Harvard where he planned a program of precise observations of Mars which were used for NASA's Mariner 9 program.

In 1960 de Vaucouleurs moved to the University of Texas at Austin, where he spent the next 35 years observing galaxies at the McDonald Observatory. It was after his move to Texas that de Vaucouleurs began producing his Reference Catalog of Bright Galaxies, the first in 1964, the second in 1976, and the third in 1991. These catalogs were a monumental effort to collect and homogenize all the basic data on 2599 bright galaxies. The observations used to produce these works led de Voucouleurs to believe that the value of the Hubble constant was about 100 km/s/mpc.

The Hubble constant (Ho) is a constant that relates the velocity (v) of a receding galaxy to the distance (d) from an observer. The Hubble law equation is: v=Hod. The law was first published in 1929 by Edwin Hubble who had noticed a relationship between the doppler redshift of spectrum lines and estimated distances from the Milky Way of receding galaxies. This law is an expression of the expansion of the universe. At the time of de Voucouleurs pronouncement, Allan Sandage and Gustav Tammann had presented a value for Ho of about 50. This dispute was unresolved for years and remained at the time of de Vaucouleurs death. Various methods have been used to estimate Ho and it is currently believed to be about 70.

De Vaucouleurs received many awards for his work, including the Herschel Medal from the Royal Astronomical Society in 1980 and the Henry Norris Russel Prize from the American Astronomical Society in 1988. He was became a member of the U. S. National Academy of Sciences in 1986.

De Vaucouleurs died on October 7, 1995.

References:

Burbidge, Margaret; "Gerard de Vaucouleurs"; in Biographical Memoirs, Vol. 82, National Academy Press; 2003

Buta, Ronald; "Gerard Henri de Vaucouleurs, 1918-1995"; Bulletin of the American Astronomical Society(1996)28:1449-1450

"In Memoriam Gerard de Vaoucouleurs" at www.utexas.edu

Hubble's Law Wikipedia Entry