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Search for microarcsecond structure in low-frequency variable radio sourcesA search for interstellar scintillation (ISS) of low-frequency variable radio sources is reported. Observations of 28 confirmed or suspected low-frequency variables, 21 nonvariable sources, and two pulsars were made at 408 MHz. As expected, the pulsars showed ISS, but scintillation was not detected in any other source. A typical upper limit to the rms modulation due to ISS is 150 mJy, giving lower limits to the apparent angular diameter of about 10 to the -6th arcsec. The possibilities that a true point source is broadened to an apparent angular diameter greater than or roughly equal to 10 to the -6th arcsec by scattering local to the source or in a general intergalactic medium are discussed.
Document ID
19780026603
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Armstrong, J. W.
(California Institute of Technology, Jet Propulsion Laboratory, Pasadena, Calif.; National Radio Astronomy Observatory, Green Bank W. Va., United States)
Spangler, S. R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hardee, P. E.
(National Radio Astronomy Observatory Green Bank, W. Va., United States)
Date Acquired
August 9, 2013
Publication Date
October 1, 1977
Publication Information
Publication: Astronomical Journal
Volume: 82
Subject Category
Astrophysics
Accession Number
78A10512
Distribution Limits
Public
Copyright
Other

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