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Time-dependent radio fine structure of the quasar 3C 345Results are reported for VLBI observations of 3C 345 at a wavelength of 3.8 cm with left circular polarization. Sixteen sets of correlated flux densities and three sets of closure phases were obtained from observations made over a three-year period with six independent interferometers formed from up to four antennas. The mathematical models employed to represent the radio brightness distribution of the source are described, and the data are analyzed on the basis of a two-component model. The results show that the compact source in 3C 345 consists of two components whose separation increased by about 0.3 milliarcsec over the observational period, that the smaller and weaker component is to the east and south of the larger and stronger one, and that the apparent expansion velocity would be about 2.5c for a redshift of 0.6, a Hubble constant of 60 km/sec per Mpc, and a deceleration parameter of unity. It is concluded that these findings are difficult to reconcile with the 'Christmas tree' model for the apparent change of separation with time over any given series of observations.
Document ID
19770033252
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wittels, J. J.
(Maryland Univ. College Park, MD, United States)
Shapiro, I. I.
(Maryland Univ. College Park, MD, United States)
Cotton, W. D.
(Maryland Univ. College Park, MD, United States)
Counselman, C. C.
(MIT Cambridge, Mass., United States)
Hinteregger, H. F.
(Maryland Univ. College Park, MD, United States)
Knight, C. A.
(Maryland Univ. College Park, MD, United States)
Rogers, A. E. E.
(Maryland Univ. College Park, MD, United States)
Whitney, A. R.
(Haystack Observatory Westford, Mass., United States)
Clark, T. A.
(Maryland Univ. College Park, MD, United States)
Hutton, L. K.
(NASA Goddard Space Flight Center; Maryland, University Greenbelt, Md., United States)
Date Acquired
August 9, 2013
Publication Date
November 1, 1976
Publication Information
Publication: Astronomical Journal
Volume: 81
Subject Category
Astrophysics
Accession Number
77A16104
Funding Number(s)
CONTRACT_GRANT: NGR-22-009-839
CONTRACT_GRANT: NSF DES-74-22712
CONTRACT_GRANT: NAS7-100
CONTRACT_GRANT: NSF MPS-71-02109-A07
Distribution Limits
Public
Copyright
Other

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