Skip to main content

Thank you for visiting 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:

The optical afterglow of the short γ-ray burst GRB 050709


It has long been known that there are two classes1 of γ-ray bursts (GRBs), mainly distinguished by their durations. The breakthrough in our understanding of long-duration GRBs (those lasting more than 2 s), which ultimately linked them with energetic type Ic supernovae2,3,4, came from the discovery of their long-lived X-ray5 and optical6,7 ‘afterglows’, when precise and rapid localizations of the sources could finally be obtained. X-ray localizations have recently become available8,9 for short (duration <2 s) GRBs, which have evaded optical detection for more than 30 years. Here we report the first discovery of transient optical emission (R-band magnitude 23) associated with a short burst: GRB 050709. The optical afterglow was localized with subarcsecond accuracy, and lies in the outskirts of a blue dwarf galaxy. The optical and X-ray10 afterglow properties 34 h after the GRB are reminiscent of the afterglows of long GRBs, which are attributable to synchrotron emission from ultrarelativistic ejecta. We did not, however, detect a supernova, as found in most nearby long GRB afterglows, which suggests a different origin for the short GRBs.

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

Access options

Buy this article

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

Figure 1: The classic BATSE duration–spectral hardness diagram1.
Figure 2: The optical afterglow of GRB 050709.
Figure 3: Light curve of the optical counterpart to GRB 050709.

Similar content being viewed by others


  1. Kouveliotou, C. et al. Identification of two classes of gamma-ray bursts. Astrophys. J. 413, L101–L104 (1993)

    Article  ADS  CAS  Google Scholar 

  2. Galama, T. J. et al. An unusual supernova in the error box of the γ-ray burst of 25 April 1998. Nature 395, 670–672 (1998)

    Article  ADS  CAS  Google Scholar 

  3. Hjorth, J. et al. A very energetic supernova associated with the γ-ray burst of 29 March 2003. Nature 423, 847–850 (2003)

    Article  ADS  CAS  PubMed  Google Scholar 

  4. Stanek, K. Z. et al. Spectroscopic discovery of the supernova 2003dh associated with GRB 030329. Astrophys. J. 591, L17–L20 (2003)

    Article  ADS  CAS  Google Scholar 

  5. Costa, E. et al. Discovery of an X-ray afterglow associated with the γ-ray burst of 28 February 1997. Nature 387, 783–785 (1997)

    Article  ADS  CAS  Google Scholar 

  6. Van Paradijs, J. et al. Transient optical emission from the error box of the γ-ray burst of 28 February 1997. Nature 368, 686–688 (1997)

    Article  ADS  Google Scholar 

  7. Metzger, M. R. et al. Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997. Nature 387, 878–879 (1997)

    Article  ADS  CAS  Google Scholar 

  8. Gehrels, N. et al. A short γ-ray burst apparently associated with an elliptical galaxy. Nature doi:10.1038/nature04142 (this issue)

  9. Villasenor, J. S. et al. Discovery of the short γ-ray burst GRB 050709. Nature doi:10.1038/nature04213 (this issue)

  10. Fox, D. B. et al. The afterglow of GRB 050709 and the nature of the short-hard γ-ray bursts. Nature doi:10.1038/nature04189 (this issue)

  11. Ghirlanda, G., Ghisellini, G. & Celotti, A. The spectra of short gamma-ray bursts. Astron. Astrophys. 422, L55–L58 (2004)

    Article  ADS  CAS  Google Scholar 

  12. Lazzati, D., Ramirez-Ruiz, E. & Ghisellini, G. Possible detection of hard X-ray afterglows of short gamma-ray bursts. Astron. Astrophys. 379, L39–L43 (2001)

    Article  ADS  Google Scholar 

  13. Connaughton, V. BATSE observations of gamma-ray burst tails. Astrophys. J. 567, 1028–1036 (2002)

    Article  ADS  Google Scholar 

  14. Barris, B. J., Tonry, J. L., Novicki, M. C. & Wood-Vasey, W. M. The NN2 flux difference method for constructing variable object light curves. Astron. J. (in the press); preprint at (2005)

  15. Amati, L. et al. Intrinsic spectra and energetics of BeppoSAX gamma-ray bursts with known redshifts. Astron. Astrophys. 390, 81–89 (2002)

    Article  ADS  Google Scholar 

  16. Berger, E. et al. A Standard kinetic energy reservoir in gamma-ray burst afterglows. Astrophys. J. 590, 379–385 (2003)

    Article  ADS  Google Scholar 

  17. Piran, T. The physics of gamma-ray bursts. Rev. Mod. Phys. 76, 1143–1210 (2005)

    Article  ADS  Google Scholar 

  18. Rosswog, S. From neutron star binaries to gamma-ray bursts. Preprint at (2005).

  19. Zhang, W., Woosley, S. E. & MacFadyen, A. I. Relativistic jets in collapsars. Astrophys. J. 586, 356–371 (2003)

    Article  ADS  Google Scholar 

  20. Yamazaki, R., Ioka, K. & Nakamura, T. A unified model of short and long gamma-ray bursts, X-ray-rich gamma-ray bursts, and X-ray flashes. Astrophys. J. 607, L103–L106 (2004)

    Article  ADS  CAS  Google Scholar 

  21. Bloom, J. S. et al. Closing in on a short-hard burst progenitor: constraints from early-time optical imaging and spectroscopy of a possible host galaxy of GRB 050509b. Astrophys. J. (in the press); preprint at (2005)

  22. Hjorth, J. et al. GRB 050509B: Constraints on short gamma-ray burst models. Astrophys. J. 630, L117–L120 (2005)

    Article  ADS  CAS  Google Scholar 

  23. Voss, R. & Tauris, T. M. Galactic distribution of merging neutron stars and black holes—prospects for short gamma-ray burst progenitors and LIGO/VIRGO. Mon. Not. R. Astron. Soc. 342, 1169–1184 (2003)

    Article  ADS  CAS  Google Scholar 

  24. Christensen, L., Hjorth, J. & Gorosabel, J. UV star-formation rates of GRB host galaxies. Astron. Astrophys. 425, 913–926 (2004)

    Article  ADS  CAS  Google Scholar 

  25. Bloom, J. S., Kulkarni, S. R. & Djorgovski, S. G. The observed offset distribution of gamma-ray bursts from their host galaxies: A robust clue to the nature of the progenitors. Astron. J. 123, 1111–1148 (2002)

    Article  ADS  Google Scholar 

  26. Fruchter, A. S. et al. The locations of cosmic explosions. Nature (submitted)

  27. Jakobsson, P. et al. Swift identification of dark gamma-ray bursts. Astrophys. J. 617, L21–L24 (2004)

    Article  ADS  CAS  Google Scholar 

  28. Li, L. X. & Paczyński, B. Transient events from neutron star mergers. Astrophys. J. 507, L59–L62 (1998)

    Article  ADS  Google Scholar 

  29. Panaitescu, A., Kumar, P. & Narayan, R. Observational prospects for afterglows of short-duration gamma-ray bursts. Astrophys. J. 561, L171–L174 (2001)

    Article  ADS  Google Scholar 

  30. Lee, W. H., Ramirez-Ruiz, E. & Granot, J. A compact binary merger model for the short, hard GRB 050509b. Astrophys. J. 630, L165–L168 (2005)

    Article  ADS  CAS  Google Scholar 

Download references


We thank T. Tauris for discussions. The Dark Cosmology Centre is funded by the DNRF. We acknowledge benefits from collaboration within the EU FP5 Research Training Network ‘Gamma-ray bursts: an enigma and a tool’.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Jens Hjorth.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Hjorth, J., Watson, D., Fynbo, J. et al. The optical afterglow of the short γ-ray burst GRB 050709. Nature 437, 859–861 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


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.


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