Paul A. Feldman
Paul started out in theory, his first paper (with Richard Epstein) identifying a trigonometric factor correction in the formulae for synchrotron radiation, followed by papers on both quasar and pulsar emission mechanisms. However, he gradually became more and more involved with observational astronomy, particularly at radio wavelengths, and later became a champion of the submm waveband, using molecular spectroscopy to study a wide range of astronomical objects. He wrote a timely review of "Infrared and Microwave Astronomy" for Nature in 1969, co-authored by Martin Rees and Mike Werner. His essay "Using Gravity to Determine the Nature of Superluminous Astronomical Objects", written with John Gribbin, won first prize in the Gravity Research Foundation competition in 1970. Around this period he was working on active stars with high mass loss and flares of magnetic origin. Soon he would describe himself as a "radio astronomer", a label he was proud to use for the rest of his career. As he wrote himself in 1999 "After postdocs at Cambridge (IOTA) and Queen's Univ. (Kingston), he taught briefly at York Univ. where Chris Purton infected him with the radio astronomy bug. He has devoted himself to feeding this illness for the past 25 years, first at DRAO, then in Ottawa, and most recently at DAO."
In 1974, along with Alan Bridle, a search was made for SETI signals in water emission at 1.35cm (the first such study) for 13 nearby stars, using the 150-foot dish at Algonquin Park. An extended survey called "Qui Appelle?" included 70 stars by 1976. Despite the null results, he was an enthusiastic supporter of the scientific search for signals of alien origin. However, he remained deeply skeptical of less scientific claims of extraterrestrial activity, delivering public lectures criticising von Daniken's books, for example, as well as being critical of his ex-supervisor Sturrock's work on UFOs.
Paul worked on a wide range of astrophysical problems. One question of lasting interest for him was the origin of the diffuse interstellar bands, particularly the possibility that carbon-chain molecules might be involved. As evidence of the breadth of his curiosity, in 1976 he helped organise a workshop discussing the causes of mass extinctions on Earth, with his own contribution dismissing the then-popular idea that a supernova may have been responsible for the death of the dinosaurs.
Paul is probably remembered best for his contributions to molecular spectroscopy at submillimetre and longer wavelengths. In 1982 he was an important member of the team that identified the molecule HC11N in the spectrum of an evolved star, with weight 147, the heaviest then known. He also used photometry to study various classes of object, including asteroids. This led to Minor Planet No. 3658 being named "Feldman", in honour of both Paul A. and his namesake Paul D. at Johns Hopkins, each of whom had studied asteroids. He was delighted to have half an asteroid named after him!
He was proud to be part of the NRC's Herzberg Institute of Astrophysics. The group in Ottawa supported Canada's involvement in the James Clerk Maxwell Telescope, which Paul used heavily from when it started operating in 1987. He relocated from Ottawa to the DAO along with the rest of the Millimetre Astronomy Group in 1996 and was included in the "Receiver B3" team, which successfully delivered an instrument to the JCMT in the midst of the move, for which they received an NRC Outstanding Achievement Award in 1998.
Paul was a member of the ODIN satellite team and was also originally a Canadian Associate Scientist on the Herschel-SPIRE team, but generously stepped aside to allow younger scientists to join. In the 1980s and 1990s his closest collaborators at the NRC were Morley Bell and Henry Matthews and through the 1990s he worked closely with Russell Redman. Along with members of the MSX satellite team, he and Redman followed up infrared-dark clouds using the JCMT.
Later in his career he became interested in the history of astronomy. He published "Grote Reber: Yesterday and Today" in Sky & Telescope in 1988. In 1998 he wrote "Interstellar Molecules from a Canadian Perspective: Part I. The Early Years" (Part II was planned, but never appeared). And in 2010, he contributed "An Epilogue to the Pre-discoveries of the Cosmic Microwave Background".
A keen gardener, this intersected with his work life when he became passionate about establishing the uniqueness of the ecology of Little Saanich Mountain. In particular he initiated and sponsored the Observatory Hill mushroom survey, a project that uncovered an astonishing number of fungal species (1450 at last count), including several described for the first time.
Paul was ever the raconteur and colleagues remember him for voluble discussions on a huge range of topics, with liberal use of hyperbole for effect. Science for him was very much a social activity - he accreted many collaborators and loved to interact with people on any scientific topic. In Ottawa he regularly gave a public talk on possible explanations for the Christmas star, and would have appreciated the irony of the planetary conjunction happening in the sky as he left us.
Paul died on the 20th of December 2020. His final resting place is appropriately in a beautiful garden, with a view of the DAO.