After his PhD, Seward joined the Lawrence Livermore National Laboratory to work on linear accelerator experiments. As part of the Livermore group, he was involved in auroral X-ray radiation experiments on the Agena aft rack of several CORONA spy satellites – including Discoverer 29 and Discoverer 31.[8][9][10] Seward then participated in the 1962 atmospheric nuclear test series in the Pacific, Operation Dominic, and launched Nike-Apache sounding rockets from Johnston Island and Kauai to measure the radiation flux from the Starfish Prime high altitude nuclear explosion.[7]
F.D. Seward and colleagues holding a recoverable rocket payload, Kauai 1962. L-R: Seward, Pete Stoering, Orville Hine, Charles Curry, Max McGee, Cal Gardner.
After the 1963 Partial Nuclear Test Ban Treaty, the Livermore team was tasked with maintaining the nation's ability to perform nuclear tests should the treaty lapse. The rockets and X-ray detectors used to measure the flux of artificial nuclear explosions were repurposed to study cosmic X-rays.[7] Seward led a research program to study extrasolar X-ray sources using sounding rockets provided by the Sandia National Laboratories, and pioneered the use of sounding rockets launched from flotation rafts in the ocean in order to study the South Atlantic Anomaly.[11]
Seward showed that the X-ray emission from the binary source Sco X-1 was thermal in nature,[12] and discovered several bright X-ray sources in the southern sky.[13][14][15] He designed detectors which operated in the soft (below 1 keV) X-ray energy band and showed that old supernova remnants emitted copiously in that energy band.[16]
In 1977 Seward moved to the Smithsonian Astrophysical Observatory to join the HEAO-B project, renamed the Einstein Observatory after its launch in 1978. Prior to Einstein, an astronomy satellite's data was reserved for the use of the developers of the satellite's instruments. With the new satellite (along with the International Ultraviolet Explorer mission which introduced the practice around the same time) any astronomer in the world could apply for observing time. Seward led the user support team and established the policies for supporting such external observers that have served as the template for subsequent missions.[17] Seward played a similar role in setting up user support for the Chandra X-ray Observatory.[18]
During the 1980s and 1990s Seward continued observing supernova remnants with the Einstein and ROSAT satellites, and discovered the remnant G13.3-1.3, as well as writing a textbook on X-ray astronomy.[19]
Seward formally retired in 2005 but as of 2024 continued to carry out active research on X-ray supernova remnants.[20] In 2024 he was awarded the biennial George Van Biesbroeck Prize, "For the establishment and implementation of the first open, peer-reviewed Guest Observer program for a Principal-Investigator-led NASA space-based observatory".[21]
Selected publications
Seward, Fred; Charles, Phil (1995). Exploring the X-ray Universe. Cambridge, UK: Cambridge University Press. ISBN0521437121.
^Seward, Frederick Whittlesey (1949). Obadiah Seward of Long Island, New York and his descendants. Goshen, NY: Privately published.
^Seward, Frederick (1958). "Inelastic Scattering of Protons by Magnesium, Chromium and Other Elements From 3.5 To 7 MeV" (Ph.D. thesis). University of Rochester.
^McCord,J (October 29, 1964). Hydra-Iris South Atlantic Program, UCRL-ID-124800 (Report). Lawrence Livermore National Laboratory.
^Toor, A.; Palmieri, T.M.; Seward, F.D. (July 1976). "Evidence for thermal X-rays from the Crab Nebula". Astrophysical Journal. 207: 96. Bibcode:1976ApJ...207...96T. doi:10.1086/154471.
^Grader, R.J.; Hill, R.W.; Seward, F.D. (1968). "Soft x-rays from a new source in the constellation Vela". Astronomical Journal. 73: 179. Bibcode:1968AJS....73R.179G.
^MacGregor, A.; Seward, F.; Turiel, I. (September 1970). "Observation of Galactic X-Ray Sources 1968 November 3". Astrophysical Journal. 161: 979. Bibcode:1970ApJ...161..979M. doi:10.1086/150598.
^Hill, R.W.; Burginyon, G.A.; Seward, F.D. (1975). "A soft X-ray survey of the Scutum-Serpens-Aquila region". Astrophysical Journal. 200: 163. Bibcode:1975ApJ...200..709H. doi:10.1086/153841.
^Hill, R.W.; Burginyon, G.A.; Seward, F.D. (1975). "The Soft X-Ray Spectra of Cassiopeia a and Tycho's Supernova Remnant". Astrophysical Journal. 200: 158. Bibcode:1975ApJ...200..158H. doi:10.1086/153772.
^Tucker, Wallace; Giacconi, Riccardo. The X-ray Universe. Harvard University Press. p. 139.
