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On 24 May 2008, Andrew Stephen Wilson passed away at the age of 61, in his home in Silver Spring, Maryland, from complications resulting from a painful spinal illness. Andrew was arguably one of the first truly multi-wavelength astronomers of his generation. His scientific work on active galactic nuclei [AGN] spanned the entire electromagnetic spectrum from the radio to the X-rays.
Andrew was born in Doncaster, Yorkshire, England, on 26 March 1947. He was the younger of two brothers whose births were separated by the Second World War. His father, Norman, came from a relatively affluent family who were coal merchants. His mother, Mary, came from a less comfortable background, one of seven children, daughter of a skilled cabinet maker/French polisher, who went through a very hard time during the depression. As a teacher, she placed enormous value on hard work and education as a way of gaining advancement in life.
When Andrew was four, the family moved to Skipton, a nice market town in the Yorkshire dales. Andrew went to a small village school until age eleven when he entered Ermysted's Grammar School. He was an enthusiastic soccer and cricket player. He never lost his enthusiasm for soccer and supported the local soccer team, Leeds United, for all his life. Andrew also followed the Yorkshire county cricket team.
Andrew's interest in astronomy stemmed from the fact that at Ermysted's Grammar School someone donated a four-inch refracting telescope, so he and his friends used to go back in the evenings to investigate the rings of Saturn, the moons of Jupiter, and various nebulae. While an undergraduate at Cambridge, Andrew joined the astronomy club and ground an 8-inch mirror by hand as a part of a telescope that he set up in the backyard of his parents' house. Andrew spent hours observing with this telescope, and it was the wonder of the family.
At Cambridge, Andrew obtained his bachelor's degree with first-class honors in 1969. During a short visit in London with his fellow students to celebrate the end of their exams, Andrew met Finnish summer student, Kaija Kettunen, whom he married in 1975 in her home town of Lieksa, Finland. They had a son, Daniel, now living in South Riding, Virginia, and a daughter, Caroline, living in Oakland, California.
In 1973, Andrew obtained his doctorate degree in physics at the Cavendish Laboratory, working under the direction of Martin Ryle, winner of the 1974 Nobel Prize in physics. Andrew's PhD was dedicated to a study of the Crab Nebula at the highest radio frequencies at which the Cambridge One-mile Telescope could operate. This work, which included both intensity and polarization data, was a triumph of perseverance and skill in the reduction of an extremely complex data set. This experience stood him in excellent stead for his future career.
After his PhD, Andrew went on to be a postdoctoral research fellow at Sterrewacht, Leiden, Netherlands, and then at the Astronomy Centre of the University of Sussex, England. By that time, Andrew wanted to leave England, because he thought that he would be able to secure a permanent position in astronomy faster in another country. He also loved traveling and getting to know other cultures, and he learned foreign languages easily. In 1978, Andrew and his wife had two choices: One was to accept a position at the European Southern Observatory in Garching and the other was to come to the University of Maryland. Together they decided to come to the United States rather than go to Germany because of the language and culture.
Andrew remained at the University of Maryland for his entire career. He was a scientist of extraordinary productivity and impact over his lifetime: He wrote more than three-hundred scientific publications and accumulated more than 11,000 citations to this large body of work. In the 1970s and 1980s, he pioneered the use of radio telescopes for the study of active galactic nuclei, writing in collaboration with his students a number of seminal papers that are still standard references in the field today.
In the last 15 years, Andrew became an avid proponent of two of NASA's Great Observatories, the Hubble Space Telescope and Chandra X-ray Observatory. Since 1985, he was NASA Interdisciplinary Scientist and member of the Science Working Group for the Chandra X-ray Observatory. He was also an adjunct astronomer at the Space Telescope Science Institute in Baltimore since 1994.
Taking advantage of this leap in technology, Andrew used these facilities to examine the environment of black holes in unprecedented detail and led a research group that was second to none in this area of research. Over the years, Andrew trained and supervised twelve Ph.D. students and more than fifteen postdoctoral research scientists, all of whom are active members of the astronomical community today.
This group's work on nearby radio galaxies (e.g., Cygnus A, M87, and Pictor A) and Seyfert galaxies (e.g., the Circinus galaxy, NGC 1068, NGC 4151, and NGC 4258) is simply outstanding, a monument to Andrew's passion and perseverance to seek a complete physical understanding of the AGN phenomenon.
Andrew was at his best in one-on-one discussions. He did not beat around the bush. He was always direct, frank, and honest, all for the sake of better science. He also never did anything halfway. Andrew was fully devoted to his science and held himself and others to the highest intellectual standards. He inspired many by his example, his discipline, and a sense of humor that was equally charming and disarming. The twinkle in his eyes and mischievous smile were sure signs that he was about to say something provocative and witty.
Andrew will be dearly missed by the entire astronomical community.
I thank Andrew's wife and brother, Kaija and Martin Wilson, for their assistance in writing this obituary.
Obituary written by: Sylvain Veilleux (University of Maryland)
BAAS Citation: BAAS, 2009, 41, 582
SAO/NASA ADS Bibcode: 2009BAAS...41..582V