John A. Galt

Canada

1925-2012

Obituary:

John Galt, one of the pioneers of Very Long Baseline Interferometry, died on Boxing Day morning, December 26, 2012.

John was the first employee of the Dominion Radio Astrophysical Observatory (DRAO) in 1959, its Director from 1962 until 1980, and, with his many novel experiments on the 26-m Telescope across a number of fields of astrophysics, helped establish the importance of radio astronomy as a scientific endeavor in Canada and raised the international profile of DRAO.

John developed a passion for all things technical and scientific in his early years. Following service as a radio artificer in the Royal Canadian Navy Volunteer Reserve during the latter part of World War II, and a BA at University of Toronto, John spent one year in the Canadian arctic, working for the Dominion Observatory in Resolute Bay on studies of the Earth’s magnetic field, before heading back to Toronto to work on both his MA and PhD in the Physics Department. He became an expert in analyzing the properties of atoms through laboratory spectroscopy, an endeavour closely related to astronomy. He spent the summer of 1952 in British Columbia working at the Dominion Astrophysical Observatory (DAO) in Victoria, where he built an early optical photometer for the Plaskett Telescope. He participated in observations of the 1954 Total Eclipse from northern Ontario.

In 1957 John was hired by the Dominion Astronomer, C. S. Beales, as the first employee of the fledgling DRAO to be located in the White Lake basin near Penticton, British Columbia. The site for DRAO had recently been identified following site tests across Canada by Jack Locke of the Dominion Observatory and Ed Argyle of the Dominion Astrophysical Observatory. Not knowing much about radio exploration of the Universe, John was immediately posted to Jodrell Bank in the UK, then the leading radio astronomy institute in the world, to gain experience in the rapidly developing field. Two years later he joined Jack Locke in the old post office building in Penticton to start the challenging task of establishing the observatory.

The summer of 1959 was a very exciting and busy time at DRAO – John was responsible for construction of the 84 foot telescope, now known as the 26-m telescope, and its control building with offices. Jack Locke noted that “the telescope was erected, the receiving equipment delivered – to be immediately modified by John Galt” (Locke, 1988 JRASC 82, 219). This spirit of technical innovation was a hallmark of John’s work.

There is little doubt that the most influential experiment in the earliest years of the observatory was the first trans-continental Very Long Baseline Interferometry (VLBI) observations, made in collaboration with NRC, the University of Toronto, and Queen’s University using the 26m with the Algonquin Radio Observatory (Broten et al. 1967, Science 156, 1592). The scientific goal was to establish the size of the newly discovered quasars, one of the hottest topics in astrophysics in the 1960s. Today, these types of observations are made relatively easily at a number of facilities around the world, but in 1967 this was a remarkable tour-de-force that required a tremendous level of expertise, resourcefulness and determination (see Galt, 1988, JRASC 82 242, for a first-hand account that captures the challenges of these experiments). This pioneering observation helped establish the international reputation of DRAO and was recognized through the award of the Rumford Medal by the American Academy of Arts and Sciences in 1971. In 2010 the Institute of Electrical and Electronics Engineers also recognized this work with the dedication of an IEEE Milestone award presented in September of 2010. It was most fitting that John was able to participate in the dedication ceremony of the plaque attached to the 26-m Telescope.

One of John’s strengths was his ability to take on exciting new areas of research across a very broad range of astrophysics. When the discovery of pulsars was announced in 1968, he jumped into the field with a significant coordinated observation with Jodrell Bank to measure the speed of the pulsar scintillation pattern (due to the Interstellar Medium) moving across the Earth (Galt and Lyne, 1972, MNRAS 158, 281). For the 1986 transit of Comet Halley, he made a long series of measurements, integrating each day into a single spectrum for the entire period that the comet was above the horizon. This was a major achievement in receiver sensitivity and stability. As the comet's velocity relative to the Sun changes, the pumping of the OH emission changes, and the OH transition swaps from emission to absorption (Galt, 1987, AJ 93, 747). He subsequently used the same equipment and techniques for observations of comets Giacobbini-Zinner and Hale-Bopp.

John was very resourceful with a strong “can-do” spirit, a skill that was essential to the success of many of the challenging experiments he undertook at DRAO. He built many of the required components from scratch. This resourcefulness extended beyond the observatory, as exemplified by many of the “gadgets” he built. Most well-known of these are the “trick” bicycles he built just for fun – these needed to be steered or pedaled in the opposite direction to normal to be ridden successfully. Many of John’s colleagues, along with many Penticton residents, can attest that they challenged the most competent of cyclists, and provided much laughter and fun for spectators!

Well into retirement, John continued observations and science with the 26-m. His last scientific papers were published in 2004, describing a challenging 6.7 GHz observation of methanol emission in star forming regions. It was only his deteriorating health that eventually stopped him from coming “to work.”

A workshop was held at DRAO Sep 22-23 2014 to celebrate John's career and to dedicate the 26-meter telescope in his honour. A number of distinguished visitors travelled to Penticton to provide an overview of the work that was done by John during his career as well as current work that has followed in the areas of John’s observational research. Many former DRAO staff returned for the dedication ceremony to watch John’s wife, Rena, and the General Manager of NRC Herzberg, Greg Fahlman, unveil the new name of the 26-m telescope, the “John A. Galt Telescope”. The name had been hidden behind a white sheet held in place by a truly Galtian contraption of twine and paper clips.

Today the 26-m telescope continues to make pioneering and novel observations very much developed and executed in the same spirit as John’s experiments. The telescope is currently being fitted with a new receiver system and updated controls to enable a survey for Zeeman splitting of the HI line. There is no doubt John would have been very enthusiastic about the Zeeman experiment, having been the first person to attempt to make these types of observations (Galt et al., 1960, MNRAS 120, 187).

Contributed by Sean Dougherty, Tom Landecker, Tim Robishaw

Reference: https://rahist.nrao.edu/galt_bio-memoir.shtml