Skip to main content
SpringerLink
Log in

Selection effects in the observed variation of spectral index with redshift

  • Published:
Astrophysics and Space Science Aims and scope Submit manuscript

Abstract

The observed dependences of the spectral indices (α) of extragalactic radio sources on redshift (z) and radio luminosity (P) are investigated taking into account the possible luminosity selection effects in bright source samples. Using the steep spectrum (α>0.5) extended (D>20 Kpc) sources from a compilation of three complete samples, the contribution of the luminosity selection effects to the observed α-z relation is quantitatively estimated.

We show that a highly significant fraction (∼54%) of the observed spectral steepening with redshift can be attributed to these luminosity selection effects present in most well-studied flux density-limited samples.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Allington-Smith, J.R.: 1984,Mon. Not. R. Astron. Soc. 209, 665.

    Google Scholar 

  • Gopal-Krishna: 1988,Astron. Astrophys. 192, 37.

    Google Scholar 

  • Herbig, T. and Readhead, A.C.S.: 1991,Astrophys. J. Suppl. Ser. 81, 83.

    Google Scholar 

  • Kapahi, V.K. and Kulkarni, V.K.: 1990,Astron. J. 97, 1.

    Google Scholar 

  • Laing, R.A. and Peacock, J.A.: 1980,Mon. Not. R. Astron. Soc. 190, 903.

    Google Scholar 

  • Laing, R.A., Riley, J.M. and Longair, M.S. 1983,Mon. Not. R. Astron. Soc. 204, 151.

    Google Scholar 

  • Onuora, L.I.: 1989,Astrophys. Space Sci. 162, 349.

    Google Scholar 

  • Onuora, L.I. and Okoye, S.E.: 1983,Astrophys. J. 270, 370.

    Google Scholar 

  • Onuora, L.I. and Ubachukwu, A.A.: 1995,Astrophys. Space Sci. 226, 91.

    Google Scholar 

  • Peacock, J.A. and Wall, J.V.: 1981,Mon. Not. R. Astron. Soc. L194, 331.

    Google Scholar 

  • Pearson, T.J. and Readhead, A.C.S.: 1988,Astrophys. J. 328, 114.

    Google Scholar 

  • Ubachukwu, A.A., Okoye, S.E. and Onuora, L.I.: 1993,Proceedings Nigerian Academy of Science 5, 62.

    Google Scholar 

  • Windhorst, R.A., Mathis, D. and Newschaefer: 1989, in: R. Kron et al. (eds.),The Edwin Hubble Centinial Symp. ASP Conf. Ser. Vol. 10, Brigham Young, Utah, p. 389.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria

    A. A. Ubachukwu

  2. Department of Industrial Physics, Enugu State University of Technology, Adada Campus, Nigeria

    A. C. Ugwoke

  3. Abia State University, Uturu, Nigeria

    J. N. Ogwo

Authors
  1. A. A. Ubachukwu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. A. C. Ugwoke
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. J. N. Ogwo
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ubachukwu, A.A., Ugwoke, A.C. & Ogwo, J.N. Selection effects in the observed variation of spectral index with redshift. Astrophys Space Sci 238, 151–157 (1996). https://doi.org/10.1007/BF00641685

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00641685

Keywords

Search

Navigation