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:

Detection of Geminga as a radio pulsar

Nature volume 389, pages 697–699 (1997)Cite this article

Abstract

Geminga was discovered as a strong γ-ray source in the constellation Gemini over two decades ago1,2, and was later detected at X-ray3 and optical4 wavelengths. X-ray pulsations5 with a period of 237 ms established that it is a rotating neutron star. Although γ-ray pulses were subsequently discovered (once the period was known) in archived data6, no evidence for radio emission (either continuum or pulsed) was found; in this respect, Geminga is different from every other neutron star with pulsed emission. Here we report the detection of pulsed 102.5-MHz radio emission from Geminga, with a period of 237 ms. The flux density varies within the range 5–500 mJy and the pulse width varies between 10 and 80 ms. The small dispersion measure (2.9 ± 0.5 pc cm−3) confirms Geminga's proximity to the Sun and establishes it as the weakest known radio pulsar. This observation poses a considerable challenge for pulsar emission models, which must now be able to explain the exceptional contrast between the strength of the γ-ray and radio emission from this object.

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

Figure 1: Examples of mean pulse profiles of Geminga for five days (dates shown at top right of each panel).
Figure 2: Pulse profile obtained when the observing window equals twice the apparent pulsar period ( P = 474 ms), this.
Figure 3: Mean pulse profiles obtained as the sum of various observing periods.

Similar content being viewed by others

References

  1. Kniffen, D. A. et al. Distribution of cosmic gamma rays in the galactic anticenter region as observed by SAS-2.in Proc. 14th Int. Cosmic Ray Conf. Vol. 1, 100–105 (Max-Planck-Institut für Extraterrestrische Physik, Munich, 1975).

    Google Scholar 

  2. Fichtel, C. E. et al. High-energy gamma-ray results from the second small astronomy satellite. Astrophys. J. 198, 163–182 (1975).

    Google Scholar 

  3. Bignami, G. F., Caraveo, P. A. & Lamb, R. C. An identification for ‘Geminga’ (2CG195+04) 1E0630+178)—A unique object in the error box of the high-energy gamma-ray source. Astrophys. J. 272, L9–L13 (1983).

    Google Scholar 

  4. Bignami, G. F. et al. Adeep optical study of the field of IE0630+178. Astrophys. J. 319, 358–361 (1987).

    Google Scholar 

  5. Halpern, J. P. & Holt, S. S. Discovery of soft X-ray pulsations from the gamma-ray source Geminga. Nature 357, 222–224 (1992).

    Article  ADS  Google Scholar 

  6. Bertsch, D. L. et al. Pulsed high-energy gamma-radiation from Geminga (1E0630+178). Nature 357, 306–307 (1992).

    Article  ADS  Google Scholar 

  7. Bignami, G. F., Gavazzi, G. & Harten, R. H. Synthesis observations of the region near the proposed new Milky Way companion at 0.610 GHz. Astron. Astrophys. 54, 951–954 (1977).

    Google Scholar 

  8. Mandolesi, N., Morigi, G. & Sironi, G. No evidence of pulsed radio emission at 325 MHz from CG195+04. Astron. Astrophys. 67, L5–L6 (1978).

    Google Scholar 

  9. Sieber, W. & Schlickeiser, R. Radio measurements in the fields of gamma-ray sources. I-CG195+04. Astron. Astrophys. 113, 314–323 (1982).

    Google Scholar 

  10. Caraveo, P. A. et al. An identification for Geminga—A review of all the available data. Adv. Space Res. 3, 77–81 (1984).

    Google Scholar 

  11. Spoelstra, T. A. Th. & Hermsen, W. Ratio observations at 21 cm wavelength in the direction of Geminga. Astron. Astrophys. 135, 135–140 (1984).

    Google Scholar 

  12. özel, M. E., Dickel, R. J. & Webber, J. S. Upper limit to any 59.35-s periodic radio emission at 18 cm for mCG195.5+4.5. Nature 285, 645–647 (1980).

    Article  ADS  Google Scholar 

  13. Seiradakis, J. H. A928 MHz search for periodicities in 2CG195+O4. Astron. Astrophys. 101, 158 (1981).

    Google Scholar 

  14. Manchester, R. N., D'Amico, N. & Tuchy, I. R. Asearch for short-period pulsars. Mon. Not. R. Astron. Soc. 212, 975–986 (1985).

    Google Scholar 

  15. Seiradakis, J. H. IAU Circ. No. 5532 (1992).

    Google Scholar 

  16. Kuzmin, A. D. & Losovsky, B. Ya. IAU Circ. No. 6559 (1997).

    Google Scholar 

  17. Shitov, Yu. P. & Pugachev, V. D. Radio pulsar Geminga. Preprint No. 33, Lebedev Physical Inst. (1997).

  18. Shabanova, T. Evidence for planet around the pulsar PSR B0329+54. Astrophys. J. 453, 779–782 (1995).

    Google Scholar 

  19. Taylor, J. H. & Cordes, J. M. Pulsar distances and the galactic distribution of free electrons. Astrophys. J. 411, 674–680 (1993).

    Google Scholar 

  20. Caraveo, P. A. et al. Parallax observations with the Hubble Space Telescope yield the distance to Geminga. Astrophys. J. 461, L91–L94 (1996).

    Google Scholar 

  21. Izvekova, V. A., Malofeev, V. M. & Shitov, Yu. P. The shapes of mean pulse profiles of pulsars radio emission at the frequency 102.5 MHz. Astron. Zh. 66, 345–354 (1989).

    Google Scholar 

  22. Bignami, G. F. & Caraveo, P. A. Geminga: it's phenomenology, it's fraternity, and it's physics. Annu. Rev. Astron. Astrophys. 34, 331–381 (1996).

    Google Scholar 

  23. Malofeev, V. M. Pulsar radio spectra.in Pulsars: Problems and Progress (eds Johnston, S., Walker, M. A. & Bailes, M.) 271–277 (ASP Conf. Ser. Vol. 105, Astron. Soc. Pacific, San Francisco, 1996).

    Google Scholar 

Download references

Acknowledgements

We thank K. Lapaev, S. Tyul'bashev, N. Shchegoleva and T. Shabanova for their help with the observations and the reduction program; W. Sieber, D. Lorimer and I. Malov for discussions and careful reading of the manuscript; and V. Shishov, R. Wielebinski and M. Kramer for discussions and support. This work was supported by INTAS and the Russian RFFI.

Author information

Authors and Affiliations

  1. Pushchino Radio Astronomy Observatory, Astro Space Center, P. N. Lebedev Physical Institute, Puschino, 142292, Moscow Reg, Russia

    V. M. Malofeev & O. I. Malov

Authors
  1. V. M. Malofeev
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. O. I. Malov
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to V. M. Malofeev.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Malofeev, V., Malov, O. Detection of Geminga as a radio pulsar. Nature 389, 697–699 (1997). https://doi.org/10.1038/39530

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/39530

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