Finding Aid to the Papers of Marshall H. Cohen, 1957-2002
|See also the Papers of Woodruff T. Sullivan III, which include a 40 minute oral interview with Cohen conducted in 1978.
Short description of collection: The Archives at The National Radio Astronomy Observatory is the repository for Marshall H. Cohen's papers on Very Long Baseline Interferometry (VLBI) and VLBI in the United States, as well as his materials related to the history and early development of the Very Long Baseline Array (VLBA). Other materials related to his career and activities are held by the California Institute of Technology Archives. Two different oral history interviews are held by the California Institute of Technology Archives and by the American Institute of Physics, Center for the History of Physics.
Biography: Marshall H. Cohen was born in Manchester, N.H. on 5 July 1926. As part of the Army Specialized Training Program in World War II, he studied Electrical Engineering at Lehigh University, Virginia Polytechnic Institute, and Ohio State University. After the war he completed the Electrical Engineering degree at OSU and stayed to obtain a PhD in Physics. He moved to Cornell University in 1954 to work on its solar radio astronomy program, and studied the polarization of solar bursts. In 1958 he became involved with the Arecibo project. At Arecibo he studied compact radio sources, and the solar wind, by measuring interplanetary scintillations.
In 1966 he moved to University of California San Diego and two years later to California Institute of Technology. In 1965 he with others started the Very Long Baseline Interferometry program in the US. VLBI quickly verified that compact radio sources were tiny, and a few years later found superluminal motion in the jets in active galactic nuclei. This motion was a major factor in the development of the relativistic beam theory of radio jets. Starting in 1971, in collaboration with Jet Propulsion Laboratory, he developed a VLBI processing laboratory at Caltech, which ultimately grew to have 16-station capability, and for a number of years was a world center for VLBI processing and analysis.
In 1989, spurred by the development of the Keck telescope on Mauna Kea, Cohen with postdocs and students built a polarimeter for the 5-meter Hale telescope and then an improved version for the 10-meter Keck telescope. He used these instruments to study active galactic nuclei and magnetic white dwarfs. He was an early proponent of the Very Long Baseline Array, and since 1994 he has been a collaborator in the 15GHz VLBA survey of motions in AGN; this program has now become the MOJAVE (Monitoring Of Jets in Active Galactic Nuclei with VLBA Experiments) survey. He has become interested in the history of radio astronomy, and has written two articles on the Owens Valley Radio Observatory, and one on the Arecibo Observatory.
[Biographical note written by Marshall H. Cohen.]
Preferred citation: National Radio Astronomy Observatory/Associated Universities, Inc. Archives, Papers of Marshall H. Cohen, <series/unit/subunit/box #>. After the initial citation, abbreviations may be used: NRAO/AUI Archives, Cohen Papers, <series/unit/subunit/box #>.
Processing notes: Initial inventory of this collection was done in April 2009 by Ellen N. Bouton. Final arrangement, description, indexing, foldering and boxing of this material by Evelyn Braintwain was begun in November 2009 and was completed in January 2009. During the processing, photocopies were made to replace thermofax sheets and newspaper clippings, fasteners were removed, and materials were removed from binders of various types. Duplicates were discarded. The finding aid was created by Bouton with assistance from Marshall H. Cohen and Kenneth I. Kellermann.
Very Long Baseline Interferometry (VLBI) Series: This series includes materials related to U.S. VLBI, the VLBI Consortium, the VLBI Network, and the Network Users Group (NUG), as well as one folder on the European VLBI Network (EVN). Materials include correspondence, notes, memos, reports, agendas, meeting minutes, meeting agendas, proposals, bylaws, budgets, NUG Newsletters, and view graph copies from 1967 through 1991. Primary correspondents are N.W. Broten, Marshall H. Cohen, William E. Howard III, Kenneth I. Kellermann, Alan Maxwell, and Ivan Pauliny-Toth. There is extensive correspondence between Cohen and Kellermann. Size: 1.75 linear feet. Click here for a listing of folders. Related materials: For other materials on VLBI see also the Records of the National Radio Astronomy Observatory, the Papers of Donald C. Backer and the Papers of Kenneth I. Kellermann.
Very Long Baseline Array (VLBA) Series: The Very Long Baseline Array consists of ten, 240-ton, 25-meter diameter dish antennas spread across the Western Hemisphere, from Hawaii to St. Croix, Virgin Islands; it is a facility of National Radio Astronomy Observatory. VLBA construction began in February, 1986, and was completed in May, 1993. This series includes materials on the history and development of the VLBA from 1965 through 1988. Included are proposals, correspondence, notes, reports, meeting minutes, viewgraphs, and memos. Original folder titles have been retained. Size: 1.0 linear feet. Click here for a listing of folders. Related materials: For other materials on the VLBA see also the Records of the National Radio Astronomy Observatory, the Papers of Kenneth I. Kellermann, the Papers of Paul A. Vanden Bout, and the Papers of A. Richard Thompson.
Radio Astronomy Research Series: This series includes notes, calculations, figures, charts, graphs, correspondence, drafts, manuscripts, grant materials, and reports related to Cohen’s research from 1967 through 1978. Included are materials on VLBI experiments, including 1971-1972 VLBI experiments with Russia, on interplanetary scintillation, and other topics. Cohen's original folder titles have been retained. Size: 0.5 linear feet. Click here for a listing of folders. Related materials: For other materials on the early US-USSR VLBI experiments see also the Green Bank Chronological Correspondence Subunit in the Records of the National Radio Astronomy Observatory.
NRAO Visiting Commmittee Series: Marshall Cohen served on the NRAO Visiting Committee from 1973-1975, and chaired the Committee in 1975. This series includes general correspondence, meeting information, and other materials for that period. Size: 0.25 linear feet.
Miscellaneous Meetings Series: This series includes notes, correspondence, minutes, reports, and other materials from meetings held between 1957 and 2002, including the October 1957 AUI Advisory Committee on Radio Astronomy meeting and the 2002 Radio Astronomy at the Fringe Workshop organized by Cohen to honor Kenneth I. Kellermann. Size: 0.25 linear feet plus 9 cassette tapes. Click here for a listing of folders.