William C. Erickson
William C. “Bill” Erickson died on September 5, 2015 in Hobart, Australia. Born in Chicago, Illinois on November 21, 1930, he received undergraduate degrees in math and physics and a Ph.D. in physics (1956) from the Univ. of Minnesota.
A visit to the Dept. of Terrestrial Magnetism of the Carnegie Institution in 1955, just after the discovery of Jovian decametric emission, led to Bill’s lifelong interest in low-frequency radio astronomy. After a Carnegie fellowship (1956-7), Bill was hired by the Convair Corporation to locate a flat site to conduct low-frequency radio astronomy. He found Clark's Dry Lake, near San Diego, where from 1958 through the late ‘80s, he developed innovative low-frequency radio telescopes.
Bill came to the University of Maryland (UMD), College Park in 1961. After convincing UMD to take over the Clark Lake facility, he was hired temporarily to help develop the Benelux Cross Antenna. He recognized that the new technique of aperture synthesis enabled a simpler design than originally envisioned, giving origin to the Westerbork Synthesis Radio Telescope.
Bill resumed his UMD position in 1963 and spent 25 years developing instruments at Clark Lake and training students. His finest telescope, the TPT, was an electronically steerable broad-band array that formed images in near real time and that was used for both solar and sidereal observations. Funding for Clark Lake ended in the early 1990s, largely owing to the limitations in resolution and sensitivity imposed by the ionosphere. When self-calibration was introduced Bill recognized that these limits could be overcome. Working with a former student, he then proposed a low-frequency array based on the infrastructure of the VLA. Funding was declined and Bill, with another former student, embarked on a less expensive system that successfully overcame the “ionospheric barrier.”
Bill’s technical savvy was sought for projects worldwide, advising the group that designed the VLA and contributing to the design of the BIMA antennas. He took part in the first VLBI experiments and conducted one of the earliest searches for magnetized extra-solar planets. His observation that 4C21.53 had a steep spectrum like the Crab pulsar foreshadowed the discovery of the millisecond pulsar.
After the closure of Clark Lake Bill retired to Bruny Island, Tasmania, with his wife Hilary Cane. They spent the next 20 summers in the US, where Bill collaborated with NRL and Hilary with the NASA’s GSFC.
Bill was the first recipient of the Grote Reber Medal “for lifetime innovative contributions to radio astronomy” (2005). A workshop, organized by his students, was held on occasion of his 74th birthday. In one of his last papers he wrote “The most enduring legacy of Clark Lake is the students that were trained there;” many went on to major roles in astronomy. A modest person, Bill attributed the legacy to Clark Lake, but the merit was entirely his!
Bill is survived by his wife Hilary, three sons, and eight grandchildren.