Milliarcsecond structure of BL Lac during outburst (original) (raw)

Nature volume 294, pages 236–238 (1981)Cite this article

Abstract

The well known object BL Lacerate is the prototype of a class of compact extragalactic sources which display rapid flux and polarization changes at radio and optical wavelengths and a nearly featureless optical spectrum1. After a period of relative quiescence, BL Lac has recently undergone a violent outburst at radio wavelengths, accompanied by rapid changes in degree of polarization and position angle (Fig. 1)2,3. For a better understanding of the physical mechanism responsible for the variable emission, we have mapped the radio structure at 5 and 10.6 GHz at three epochs during the large flux outburst of 1980 with an intercontinental VLBI array using telescopes in Bonn, West Germany; Green Bank, West Virginia; Westford, Massachusetts; Fort Davis, Texas; and Owens Valley, California. The synthesized beam had a resolution of about 1.0 m arc s at λ 6 cm and 0.5 m arc s at λ 2.8 cm, corresponding to linear sizes of 5.9 and 2.9 lyr (light year) at the source (using a redshift4 of 0.0695 and a Hubble constant of 55 km s−1 Mpc−1). We show here that comparison of the size and flux density of the core component with the flux history provides evidence for relativistic beaming effects, independent of detailed model considerations. The flux densities shown in Fig. 1 were obtained at the University of Michigan radio observatory.

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

Access options

Subscribe to this journal

Receive 51 print issues and online access

$199.00 per year

only $3.90 per issue

Buy this article

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

Additional access options:

Similar content being viewed by others

References

  1. Stein, W. A. in Pittsburgh Conf. on BL Objects (University of Pittsburgh, Pennsylvania, 1978).
    Google Scholar
  2. Aller, M. F., Aller, H. D. & Hodge, P. E. Bull. Am. astr. Soc. 12, 803 (1981).
    ADS Google Scholar
  3. Aller, H. D., Aller, M. F. & Hodge, P. E. Astr. J. 86, 325 (1981).
    Article ADS CAS Google Scholar
  4. Miller, J. S., French, H. B. & Hawley, S. A. Astrophys. J. Lett. 219, L85 (1978).
    Article ADS Google Scholar
  5. Clark, B. G. IEEE 61, 1242 (1973).
    Article ADS Google Scholar
  6. Readhead, A. C. S. & Wilkinson, P. N. Astrophys. J. 223, 25 (1978).
    Article ADS Google Scholar
  7. Clark, B. G. et al. Astrophys. J. Lett. 182, L57 (1973).
    Article ADS Google Scholar
  8. Kellermann, K. I. et al. Astrophys. J. 211, 658 (1977).
    Article ADS Google Scholar
  9. Shaffer, D. B. in Pittsburgh Conf. on BL Objects (University of Pittsburgh, Pennsylvania, 1978).
    Google Scholar
  10. Pearson, T. J. & Readhead, A. C. S. Astrophys. J. 248, 671 (1981).
    Article Google Scholar
  11. Blandford, R. D. & Königl, A. Astrophys. J. 232, 34 (1979).
    Article ADS CAS Google Scholar
  12. Readhead, A. C. S. Phys. Scr. 21, 662 (1980).
    Article ADS CAS Google Scholar
  13. Scheuer, P. A. G. & Readhead, A. C. S. Nature 277, 182 (1979).
    Article ADS Google Scholar
  14. Kellermann, K. I. & Pauliny-Toth, I. I. K. A. Rev. Astr. Astrophys. (in the press).

Download references

Author information

Authors and Affiliations

  1. Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa, 52242, USA
    R. L. Mutel
  2. Department of Astronomy, The University of Michigan, Ann Arbor, Michigan, 48109, USA
    H. D. Aller
  3. Department of Physics, The University of Kansas, Lawrence, Kansas, 55044, USA
    R. B. Phillips

Authors

  1. R. L. Mutel
    You can also search for this author inPubMed Google Scholar
  2. H. D. Aller
    You can also search for this author inPubMed Google Scholar
  3. R. B. Phillips
    You can also search for this author inPubMed Google Scholar

Rights and permissions

About this article

Cite this article

Mutel, R., Aller, H. & Phillips, R. Milliarcsecond structure of BL Lac during outburst.Nature 294, 236–238 (1981). https://doi.org/10.1038/294236a0

Download citation