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The Evolution of Linear Sizes

Published online by Cambridge University Press:  14 August 2015

V. K. Kapahi  and
C. R. Subrahmanya
V. K. Kapahi
Affiliation:
Tata Institute of Fundamental Research, P.B. No. 1234, Bangalore 560012, India
C. R. Subrahmanya
Affiliation:
Tata Institute of Fundamental Research, P.B. No. 1234, Bangalore 560012, India

Extract

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Possible evidence that the linear sizes of extragalactic radio sources were smaller at earlier epochs was first provided by the angular size redshift (θ-z) relation for double radio quasars (Legg 1970, Miley 1971, Wardle and Miley 1974). But because of the strong correlation between redshift (z) and radio luminosity (P) in flux limited radio samples, it is hard to decide if the observed decrease in sizes with z is caused by an epoch dependence of linear sizes (ℓ) or by an inverse correlation between P and ℓ. Several authors (eg. Stannard and Neal 1977, Wardle and Potash 1977, Hooley ET AL. 1978, Wills 1979, Masson 1980) have attempted to separate the two effects by comparing the properties of quasars from the 3CR survey with those from the 4C and Parkes samples. Although most of these studies appear to marginally favour a P-ℓ correlation, none of them can rule out even a fairly strong evolution in ℓ with z. Apart from the small numbers involved, the difficulty is that 3C and 4C quasars do not differ a great deal in their redshifts or luminosities. A complete sample of quasars at much weaker flux levels would be quite valuable in this regard.

Type
Research Article
Information
Symposium - International Astronomical Union , Volume 97: Extragalactic Radio Sources , 1982 , pp. 401 - 410
Copyright
Copyright © Reidel 1982 

References

Downes, A.J.B., Longair, M.S. and Perryman, M.A.C. 1981, Mon. Not. R. astr. Soc., in press.Google Scholar
Gunn, J.E., Hoessel, J.G., Westphal, J.A., Perryman, M.A.C. and Longair, M.S. 1981, Mon. Not. R. astr. Soc., 194, 111.CrossRefGoogle Scholar
Hooley, T.A., Longair, M.S. and Riley, J.M. 1978, Mon. Not. R. astr. Soc., 182, 127.Google Scholar
Jenkins, C.J., Pooley, G.G. and Riley, J.M. 1977, Mem. R. astr. Soc., 84, 61.Google Scholar
Joshi, M.N. and Singal, A.K. 1980, Mem. Astron. Soc. India, 1, 49.Google Scholar
Kapahi, V.K. 1975, Mon. Not. R. astr. Soc., 172, 513.CrossRefGoogle Scholar
Kapahi, V.K. 1977, in IAU Symposium 74 “Radio Astronomy and Cosmology”, ed. Jauncey, D., p. 119.Google Scholar
Kapahi, V.K. 1981a, Astron. Astrophys. Suppl., 43, 381.Google Scholar
Kapahi, V.K. 1981b, in preparation.Google Scholar
Katgert, P. 1977, Ph. D. Thesis, University of Leiden.Google Scholar
Katgert-Merkelijn, J., Lari, C. and Padrielli, L. 1980, Astron. Astrophys. Suppl., 40, 91.Google Scholar
Legg, T.H. 1970, Nature, 226, 65.Google Scholar
Masson, C.R. 1980, Astrophys. J., 242, 8.Google Scholar
Miley, G.K. 1971, Mon. Not. R. astr. Soc., 152, 477.Google Scholar
Padrielli, L., Kapahi, V.K. and Katgert-Merkelijn, J.K. 1981, Astron. Astrophys. Suppl., in press.Google Scholar
Peacock, J.A. and Wall, J.V. 1981, Mon. Not. R. astr. Soc., in press.Google Scholar
Robertson, J.G. 1973, Austr. J. Phys., 26, 403.Google Scholar
Stannard, D. and Neal, D.S. 1977, Mon. Not. R. astr. Soc., 179, 719.Google Scholar
Swarup, G. 1975, Mon. Not. R. astr. Soc., 172, 501.Google Scholar
Swarup, G. and Subrahmanya, C.R. 1977, in IAU Symposium 74 “Radio Astronomy and Cosmology”, ed. Jauncey, D., p. 125.Google Scholar
Swarup, G., Subrahmanya, C.R. and Venkatakrishna, K.L. 1981, Astron. Astrophys., submitted.Google Scholar
Véron, P. 1977, Astron. Astrophys. Suppl., 30, 131.Google Scholar
Wall, J.V., Pearson, T.J. and Longair, M.S. 1980, Mon. Not. R. astr. Soc., 193, 683.Google Scholar
Wardle, J.F.C. and Miley, G.K. 1974, Astron. Astrophys., 30, 305.Google Scholar
Wardle, J.F.C. and Potash, R. 1977, Ann. NY Acad. Sci., 302, 605.Google Scholar
Wills, D. 1979, Astrophys. J. Suppl., 39, 291.Google Scholar