Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Solving the mystery of the X-ray periodicity in the Seyfert galaxy NGC6814

Nature volume 365, pages 626–628 (1993)Cite this article

Abstract

ACTIVE galaxies, of which Seyfert galaxies are a subgroup, are thought to be powered by the accretion of gas onto a massive black hole at the galaxy centre; the X-rays emitted by active galactic nuclei arise from the heated, Mailing gas. The observed rapid variability of this X-ray emission requires a compact source, providing additional support for the black-hole hypothesis. The Seyfert galaxy NGC6814 has been thought to be unique among active galaxies, in exhibiting not simply variability but a periodicity of ∼12,100 s in its X-ray luminosity1–4. Many exotic theories have been proposed to explain this periodicity, including gravitational lensing of hotspots on the accretion disk by the central black hole5–7 or the effects of a captured star orbiting the black hole4,8–10. Here we show, using data from the Rosat X-ray telescope, that although the 12,100 s period is indeed real and stable, it is not associated with NGC6814. Instead, the periodic emission arises from another source, 37 arcmin away from NGC6814, which is probably an object in our Galaxy―for example, a white dwarf accreting gas (from a giant companion) onto its poles.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

References

  1. Mittaz, J. P. D. & Branduardi-Raymont, G. Mon. Not. R. astr. Soc. 238, 1029–1046 (1989).

    Article  ADS  CAS  Google Scholar 

  2. Fiore, F., Massaro, E. & Barone, P. Astr. Astrophys. 261, 405–414 (1992).

    ADS  Google Scholar 

  3. Done, C. et al. Astrophys. J. 400, 138–152 (1992).

    Article  ADS  CAS  Google Scholar 

  4. King, A. & Done, C. Mon. Not. R. astr. Soc. (in the press).

  5. Abramowicz, M., Bao, G., Lanza, A. & Zhang, X.-H. Astr. Astrophys. 245, 454–456 (1991).

    ADS  Google Scholar 

  6. Abramowicz, M. A. et al. in The Physics of Active Galactic Nuclei (eds Wagner, S. & Dushl, W. J. 61–66 (Springer, Heidelberg, 1992).

    Book  Google Scholar 

  7. Abramowicz, M., Bao, G., Karas, V. & Lanza, A. Astr. Astrophys. 272, 400–406 (1993).

    ADS  Google Scholar 

  8. Syer, D., Clarke, C. J. & Rees, M. J. Mon. Not. R. astr. Soc. 250, 505–512 (1991).

    Article  ADS  Google Scholar 

  9. Sikora, M. & Begelman, M. C. Nature 356, 224–225 (1992).

    Article  ADS  Google Scholar 

  10. Chakrabarti, S. K. Astrophys. J. 411, 610–613 (1993).

    Article  ADS  Google Scholar 

  11. Clements, E. D. Mon. Not. R. astr. Soc. 197, 829–834 (1981).

    Article  ADS  Google Scholar 

  12. Davies, S. R. Mon. Not. R. astr. Soc. 244, 93–95 (1990).

    ADS  Google Scholar 

  13. Davies, S. R. Mon. Not. R. astr. Soc. 251, 64p–65p (1991).

    Article  ADS  Google Scholar 

  14. Elvis, M., Lockman, F. J. & Wilkes, B. Astr. J. 97, 777–782 (1989).

    Article  ADS  CAS  Google Scholar 

  15. Patterson, J. Astrophys. J. Suppl. Ser. 54, 443–493 (1984).

    Article  ADS  Google Scholar 

  16. Kunieda, H. et al. Nature 345, 786–788 (1990).

    Article  ADS  CAS  Google Scholar 

  17. Turner, T. J., Done, C., Mushotzky, R. F., Madejski, G. M. & Kunieda, H. Astrophys. J 391, 102–110 (1992).

    Article  ADS  CAS  Google Scholar 

  18. Cordova, F. in X-ray Binaries (eds Lewin, W. H. G., van Paradijs, J. & van der Heuvel, E. P. J.) (in the press).

  19. Tennant, A., Mushotzky, R. F., Boldt, E. A. & Swank, J. H. Astrophys. J. 251, 15–25 (1981).

    Article  ADS  Google Scholar 

  20. Leighly, K., Kunieda, H., Tsusaka, Y., Awaki, H. & Tsuruta, S. Astrophys. J. (in the press).

  21. Hayakawa, S. Nature 351, 214–215 (1991).

    Article  ADS  CAS  Google Scholar 

  22. Ishida, M. thesis, Univ. Tokyo (1991).

  23. McHardy, I. in Two Topics in X-ray Astronomy, Proc. 23rd ESLAB Symposium (eds White, N, Hunt, J. & Battrick, B. 1111–1124 (European Space Agency, Paris, 1989).

    Google Scholar 

  24. Fabian, A. C. in Frontiers of X-ray Astronomy, (eds Tanaka, Y. & Koyama, K.) 603–610 (Universal Academy, Tokoyo, 1992).

    Google Scholar 

  25. Rosen, S., Done, C., Watson, M. & Madejski, G. IAU Circ. No. 5850.

Download references

Author information

Author notes

  1. Chris Done

    Present address: Physics Department, Leicester University, Leicester, UK

Authors and Affiliations

  1. Laboratory for High Energy Astrophysics, Code 666, NASA, Goddard Space Flight Center, Greenbelt, Maryland, 20771, USA

    Greg M. Madejski, Chris Done, T. Jane Turner, Richard F. Mushotzky & Peter Serlemitsos

  2. Universities Space Research Association,

    Greg M. Madejski & T. Jane Turner

  3. Center for Astrophysics, Cambridge, Massachusetts, 02138, USA

    Fabrizio Fiore

  4. Copernicus Astronomical Center, Bartycka 18, 00–716, Warsaw, Poland

    Marek Sikora

  5. Joint Institute for Laboratory Astrophysics, University of Colorado, Boulder, Colorado, 80309, USA

    Marek Sikora & Mitchell C. Begelman

  6. Department of Astrophysical, Planetary, and Atmospheric Sciences, University of Colorado, Boulder, Colorado, 80309, USA

    Mitchell C. Begelman

Authors
  1. Greg M. Madejski
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Chris Done
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. T. Jane Turner
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Richard F. Mushotzky
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Peter Serlemitsos
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Fabrizio Fiore
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Marek Sikora
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Mitchell C. Begelman
    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

Madejski, G., Done, C., Turner, T. et al. Solving the mystery of the X-ray periodicity in the Seyfert galaxy NGC6814. Nature 365, 626–628 (1993). https://doi.org/10.1038/365626a0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/365626a0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing