Maxwell, a solar radio astronomer, founded the Harvard College Observatory’s Radio Astronomy Station and was co-discoverer of a new type of low-frequency solar radio burst. He was also a founding editor of the journal Astrophysical Letters.
Alan Maxwell died on Sunday, August 22, 2021. He was 94.
Alan Maxwell was born on October 21, 1926, in Auckland, New Zealand, into a prosperous merchant family. He was the only child of Arthur and Ellen Maxwell. His paternal great-grandparents emigrated from England to New Zealand in 1859. His maternal great-grandmother, a descendant of a prominent Māori family from the southern New Zealand town of Bluff, married a British sea captain named Bradshaw according to family lore. Three generations later, Alan grew up in the sedate Auckland suburb of Northcote.
Alan was a precocious musician and gave his first organ recital at the Auckland Town Hall at age 16. He played regularly during services at St. Mary’s Cathedral in Auckland. He studied physics at the University of Auckland and obtained his B.Sc. and M.Sc. degrees in 1947 and 1949, respectively. For his master’s thesis, “Enhanced Solar Radiation at 3-Metre Wavelengths,” he observed the radio emission from the Sun and attempted to correlate the radio bursts with sunspot activity. For these measurements, he adapted a war-surplus radar system with a dual five-element Yagi antenna, which he installed on the roof of a university building. He worked with his advisor, Kurt Kreielsheimer, in a department led by the distinguished physicist and radar pioneer, Percy Burbidge. His was the first thesis written in the nascent field of radio astronomy.
In 1950, Alan enrolled in the graduate program in physics at Manchester University, U.K., and immediately began helping Francis Graham-Smith, C. Gordon Little, and Bernard Lovell in their experiments that proved that the rapid fluctuations, known as scintillations, of the radio source Cygnus A were not intrinsic but were caused by plasma irregularities in the F layer of the Earth’s ionosphere. Alan’s Ph.D. thesis, “A Radio Astronomical Investigation of the Upper Atmosphere,” was completed in 1953 under the direction of Lovell and Little. For that work, he set up spaced antennas to study scintillations of cosmic radio sources in detail, and he was able to measure wind speeds in the ionosphere.
Alan stayed on at Manchester as a lecturer until 1955, when Donald Menzel of Harvard University hired him to help further his plan for increasing the US involvement in solar radio astronomy in preparation for the International Geophysical Year (1957–58). Alan founded the Harvard Radio Astronomy Station in southwest Texas near the town of Fort Davis. He located and leased land on the Sproul family ranch that offered good isolation from radio interference as well as proximity to McDonald Observatory. He equipped it with a 28-foot radio telescope built by the D. S. Kennedy Corporation to monitor solar radio emission.
In 1958, Alan and his young assistant, Govind Swarup, discovered a new type of radio burst, which they called the “U burst” based on its signature in plots of intensity vs. time and frequency. Alan enlarged the facility by securing funds to build an 85-foot antenna for solar and general radio astronomy. Erected in 1963, it was a copy of the 85-foot antenna built for the National Radio Astronomy Observatory in 1958 by the Blaw-Knox Corporation of Pittsburgh, a manufacturer of steel structures. The solar monitoring program was carried out continuously until 1982. Alan’s observations helped establish the link between solar flares and geophysical phenomena. All of the data, recorded on 35-mm film, were sent to the archives of the National Oceanographic and Atmospheric Administration. Because of Fort Davis’s mid-continental location, in 1976, it became a critical node in the U.S. Very Long Baseline Network (VLBN), the predecessor of the Very Long Baseline Array (VLBA). The VLBN program ended in 1991, and operations were transferred to a new VLBA antenna at the same location.
Alan’s most notable students were Dennis Downes and Joseph Taylor. Downes (Ph.D. 1970) made surveys of radio sources in the Galactic plane. Taylor (Ph.D. 1968 and Nobel laureate 1993) studied the structure of radio sources via lunar occultation. In a 2001 oral history interview for the American Institute of Physics, Taylor said, “Alan Maxwell was a great advisor … He opened doors, helped me gain access to big telescopes, and introduced me to the right people … We talked almost every day.” However, some of his colleagues found Alan irascible at times and challenging to work with.
Alan and Evry Schatzman were the founding editors of Astrophysical Letters, “an international express journal,” published by Gordon & Breach Science Publishers. Conceived to rapidly publish short articles of significance, it fulfilled an unmet need at the time. It had a distinguished publications board that included Jesse Greenstein, Jan Oort, Martin Ryle, and Josif Shklovsky. Maxwell and Schatzman edited the journal from 1967 to 1973 (volumes 1–15). They were followed by Stephen Maran and Richard Henry. In 1988, the scope of the journal was expanded, and it was renamed Astrophysical Letters and Communications, under the editorship of Giorgio Palumbo. It ceased publication in 2000, about the time when Gordon & Breach was acquired by the Taylor & Francis Group.
Alan was a fellow of both the Royal Astronomical Society and the Physical Society of London (now the Institute of Physics) and a member of the International Astronomical Union, the International Union of Radio Science, the American Astronomical Society, the Australian Astronomical Society, and the Institute of Electrical and Electronic Engineers.
Having retired in 1983 from his positions as a senior research associate at Harvard College Observatory (which had the become part of the Harvard-Smithsonian Center for Astrophysics) and a lecturer in Harvard’s Astronomy Department, Alan continued to come to the Observatory most days thereafter when he was residing in Cambridge. He traveled extensively, never married or put down roots, and lived in the Hotel Commander and other local hotels while in Cambridge. He died in San Diego, in transit between Auckland and Cambridge, where he was “stranded” for 18 months during the COVID-19 pandemic. He died peacefully after a brief, non-COVID-19 related illness. A relative gathered his possessions into two small suitcases. He never used a computer or owned a cell phone.
Alan Maxwell’s legacy includes his scientific discoveries and the substantial achievements of his students. Three of his alma maters — the University of Auckland, the University of Manchester, and Harvard University — will benefit from his bequests for graduate education in physics and astronomy.