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Alignment of distant radio sources


A typical extragalactic radio source is a simple double or elongated structure with a well-defined orientation on the sky. In 1972, Willson1 investigated the relative orientation of 74 extragalactic 3C radio sources mapped at the Cambridge 1-mile telescope, and noted that extended extragalactic radio sources tend to be parallel if they are separated by less than 10° on the sky. Since 1972, many more radio sources have been mapped with resolutions 10–20 times greater than that of the observations available to Willson. I have therefore reinvestigated this problem in two separate and largely independent samples of some 300 sources each, and report here that the alignment is present to a high significance level, provided that only the more distant sources are considered. The effect could be due to gravitational imaging if most of the matter in a closed universe is in thin filaments.

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  1. Willson, M. A. G. Mon. Not. R. astr. Soc. 155, 275–282 (1972).

    Article  ADS  Google Scholar 

  2. Laing, R. A., Riley, J. M. & Longair, M. S. Mon. Not. R. astr. Soc. 204, 151–187 (1983).

    Article  ADS  Google Scholar 

  3. Pooley, G. G. & Henbest, S. N. Mon. Not. R. astr. Soc. 169, 477–526 (1974).

    Article  ADS  Google Scholar 

  4. Riley, J. M. & Pooley, G. G. Mem. R. astr. Soc. 80, 105–137 (1975).

    ADS  Google Scholar 

  5. Jenkins, C. J., Pooley, G. G. & Riley, J. M. Mem. R. astr. Soc. 84, 61–99 (1977).

    ADS  Google Scholar 

  6. Laing, R. A. Mon. Not. R. astr. Soc. 194, 301–330 (1981).

    Article  ADS  Google Scholar 

  7. Laing, R. A. Mon. Not. R. astr. Soc. 195, 261–324 (1981).

    Article  ADS  Google Scholar 

  8. Hintzen, P., Ulvestad, J. & Owen, F. Astr. J. 88, 709–758 (1983).

    Article  ADS  Google Scholar 

  9. Miley, G. & Hartsuijker, A. Astr. Astrophys. Suppl. 34, 129–163 (1983).

    ADS  Google Scholar 

  10. Owen, F., Porcas, R. & Neff, S. Astr. J. 83, 1009–1020 (1979).

    Article  ADS  Google Scholar 

  11. Potash, R. & Wardle, J. Astr. J. 84, 707–717 (1979).

    Article  ADS  Google Scholar 

  12. Siegel, S. Non-parametric Statistics (McGraw-Hill, New York, 1956)

    Google Scholar 

  13. Sanders, R. H., van Albada, T. S. & Oosterloo, T. Astrophys. J. (in the press).

  14. Oort, J. H. A. Rev. Astr. Astrophys. 21, 373–428 (1983).

    Article  ADS  Google Scholar 

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Sanders, R. Alignment of distant radio sources. Nature 309, 35–37 (1984).

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