Frank John Kerr died on 15 September 2000 at his home in Silver Spring, MD. He is survived by his sister Valerie Kerr, son Ian Kerr, daughter Robin Lowry, and four grandchildren, Sean, Kathryn, Alyssa and Talulah, all in Australia. His first wife Kathleen Royce, his second wife Maureen Parnell and his daughter Gillian predeceased him. He was a councilor of the AAS from 1972 to 1975 and a vice-president from 1980-1982, a member of the US National Committee for the International Astronomical Union (IAU) from 1975 to 1977 and of the organizing committee for the IAU General Assembly in 1988.
Born on 8 January 1918 in St Albans, England, to a well-known Australian physician's family temporarily in England, he received his BSc in physics at the University of Melbourne, Australia, in 1938 followed by an MSc in 1940, while holding scholarships from 1935 to 1940 and winning the Ormsby Hamilton prize in 1939. His Master's research resulted in a 1941 paper on the refractive index of gases at radio frequencies. The war prevented him from going to Cambridge University in England for his PhD. He was awarded a DSc by the University of Melbourne in 1962.
In 1940 he joined the Radiophysics Laboratory of the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Sydney. Among the 12 people there at the time, he was one of the few physicists, concentrating on fundamental science, both theoretical and experimental. He wrote many reports on receivers, antennas, and fundamentals of waveguides. In 1941 he put into use the "Micropup," a lightweight air-cooled triode tube for airborne radar, with 10 kW peak pulse at 450 MHz, and later was a key person in the use of the Magnetron. From 1944 to 1946 he studied super-refraction. By then, the Radiophysics Lab had 300 employees!
In 1948, using the Radio Australia transmitting antenna with a 100 kW transmitter, pointed at the US, and a CSIRO built receiving antenna elsewhere, he obtained radio echoes of the Moon. He was the first to conclude that there are serious irregularities at the top of the F2 ionospheric layer causing long-term variations in the Moon echo, and correctly interpreted the strong short-term fluctuations due to lunar libration. In 1952 he published the classic paper on the possibilities of radar echoes from the planets and the Sun. His Moon-echo work was epoch-making. In 1951 he received a Fulbright travel grant and a research scholarship to Harvard, where he received an MA. He was the first person at the Radiophysics Lab to specifically study astronomy, even though the group was already one of the world's leading organizations in radio astronomy. While taking a course in radio astronomy from van de Hulst, who was visiting from The Netherlands, he witnessed the first detection of the 21-cm spectral line of neutral hydrogen in interstellar space. Back in Australia, he set up the Southern Hemisphere 21-cm line program and started mapping the Magellanic Clouds. This was another pioneering set of observations, the first detection of a radio spectral line in an external galaxy. According to conventional wisdom, since there is almost no dust, especially in the small cloud, there will be no gas. However, not discouraged by this, Frank found copious amounts of neutral hydrogen and an extended envelope around both clouds. He used a specially built 36-foot transit telescope, which at that time was the largest dish of its kind in Australia.
In 1954 and 1955 he went on with Hindman, Robinson, de Vaucouleurs, and others to determine the rotation of the Magellanic Clouds and their masses. It was another first. He then started mapping the Galactic disk, and shortly after the 1955 Dutch map of the Northern hemisphere, he published the Southern extension. There, he noted for the first time that the upswing of the Galactic Hydrogen layer observed in the Northern part of the Galaxy was mirrored by a downswing in the Southern part. In 1956, he coined the words "Galactic Warp" and suggested that it might be a gravitational effect due to the Magellanic Clouds. During this period, Bart Bok, who was then director of the Mt. Stromlo Observatory, was a tireless source of encouragement. Joining forces with the Dutch radio astronomers, he determined with Gum and Westerhout the precise position of the plane of the neutral hydrogen. That determination was adopted in 1958 by the IAU as the basis for the new galactic coordinate system. By 1960, in a short eight years as an astronomer, Frank Kerr had become a leading expert in the field of galactic structure. He was heavily involved in the conceptual studies for the Parkes 210-foot radio telescope and pushed for a very accurate surface (good to 10-cm wavelength) in order to make it perfect for his planned 21-cm line research programs. Observations with the telescope began in 1962 and he embarked on an extensive galactic structure program, the results of which were published in a long series of papers ending in 1971. In the meantime, Frank had organized several symposia, given many invited papers, and had held several visiting scientist positions in the US, The Netherlands and elsewhere. In 1960 he became a senior principal research officer at CSIRO.
In 1966 he made the difficult decision to leave his beloved Australia and moved to the University of Maryland, first as a visiting professor and, in 1968, as professor, which position he held until his retirement in 1987. But he did not lose his interest in the Southern hemisphere. Twice, in 1968 and 1970, he went to Argentina, where he amazed the local astronomers with his tenacious observing, and several times in the 1970s, joined by some of his students, he went back to Australia, in order to make a complete 21-cm survey along a 20-degree strip of the Southern Milky Way. During these foreign observing sessions, he was always ably assisted by his wife Maureen. Late in his career, between 1986 and 1990, he successfully searched for evidence of galaxies hidden behind the Milky Way dust layer (the zone of avoidance), opening an entirely new and very active field of research.
Frank Kerr was director of the Astronomy Program at the University of Maryland from 1973-1978, Provost of the Division of Physical and Mathematical Sciences and Engineering from 1978-1985 and director of the Division of Astronomy and Space Physics of the Universities Space Research Association (USRA) from 1983-1995. He was chairman of the National Science Foundation (NSF) advisory Panel on Astronomy from 1971-1972. He was a member of numerous working groups, advisory committees, and visiting committees, Trustee of Associated Universities Inc. (AUI) from 1981-1984, and chairman of the USRA Council of Institutions from 1984-1985. He received a Guggenheim fellowship in 1975. On the international scene, he organized six IAU Symposia, and was on the organizing committee of IAU Commission 33 on Galactic Structure from 1967-1982 and its President from 1976-1979. From 1982-1986 he chaired an IAU working group that recommended new standard values for the size and rotation properties of the Galaxy. He published 87 refereed papers, 14 invited papers and over 85 contributed papers, books and contributions to books. Upon his retirement in 1987, Frank Kerr was honored with a three-day symposium on "The Outer Galaxy" (Blitz and Lockman, 1988) which contains a 20-page biographical article by W.T. Sullivan.
Frank was truly a Renaissance man. He possessed a great love and encyclopedic knowledge of the English language—equally ready to explain the origin of an Australian colloquialism or to quote a Latin proverb. He had a great love for music and, already as a young man, used to follow a symphony with the score on his lap. At the same time, he was a real sports aficionado—from Australian rules football to cricket, baseball and American football. His students often wondered how such a gentle man could be so engrossed in violent football. When an important baseball or football game was on during an observing session, the telescope was put into automatic so he and his students could watch the game. He was a superb teacher and supervised 13 PhD theses. His many students are unanimous in calling him a great mentor and an example to be followed: honest, considerate, ambitious, literate, intelligent, precise, proud, diligent, and confident. Up until the end of his life he and those ex-students—now colleagues—in the neighborhood went out for lunch together once a month. His scientific colleagues around the world have lost a great leader in science and humanity.
Photo courtesy of the University of Maryland