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.

The afterglow of GRB 050709 and the nature of the short-hard γ-ray bursts


The final chapter in the long-standing mystery of the γ-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

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

Access options

Rent or buy this article

Get just this article for as long as you need it


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

Figure 1: HST and Chandra X-ray Observatory images of the afterglow and environs of GRB 050709.
Figure 2: Spectrum of the host galaxy of GRB 050709.
Figure 3: Observations of the GRB 050709 afterglow and illustrative models.
Figure 4: Physical properties of the afterglows of long-duration GRBs (histograms) and SHBs (arrows).


  1. Zhang, B. & Meszaros, P. Gamma-ray bursts: progress, problems & prospects. Int. J. Mod. Phys. A19, 2385–2472 (2004)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  3. Hurley, K. et al. Afterglow upper limits for four short-duration, hard spectrum gamma-ray bursts. Astrophys. J. 567, 447–453 (2002)

    Article  ADS  Google Scholar 

  4. Kulkarni, S. R. et al. Supernova and low-velocity ejecta constraints for the short-hand γ-ray burst GRB 050509B. Nature (submitted)

  5. 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 (submitted)

  6. Gehrels, N. et al. A short γ-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225. Nature doi:10.1038/nature04142 (this issue)

  7. Schmidt, M. Luminosities and space densities of short gamma-ray bursts. Astrophys. J. 559, L79–L82 (2001)

    Article  ADS  Google Scholar 

  8. Eichler, D., Livio, M., Piran, T. & Schramm, D. N. Nucleosynthesis, neutrino bursts and gamma-rays from coalescing neutron stars. Nature 340, 126–128 (1989)

    Article  ADS  Google Scholar 

  9. Guetta, D. & Piran, T. The luminosity and redshift distributions of short-duration GRBs. Astron. Astrophys. 435, 421–426 (2005)

    Article  ADS  CAS  Google Scholar 

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

  11. Garmire, G. P., Bautz, M. W., Ford, P. G., Nousek, J. A. & Ricker, G. R. in X-Ray and Gamma-Ray Telescopes and Instruments for Astronomy (eds Truemper, J. E. & Tananbaum, H. D.) Proc. SPIE. 4851, 28–44 (2003).

  12. Condon, J. J. et al. The NRAO VLA Sky Survey. Astron. J. 115, 1693–1716 (1998)

    Article  ADS  Google Scholar 

  13. Fox, D. B., Frail, D. A., Cameron, P. B. & Cenko, S. B. GRB050709: candidate X-ray afterglow. GRB Circ. Netw. 3585 (2004)

  14. Burrows, D. N. et al. Bright X-ray flares in gamma-ray burst afterglows. Science 150, 1–5 (2005)

    Google Scholar 

  15. Jensen, B. L. et al. GRB 050709: Chandra source optical counterpart. GRB Circ. Netw. 3589 (2005)

  16. Hjorth, J. et al. The optical afterglow of the short γ-ray burst GRB 050709. Nature doi:10.1038/nature04174 (this issue)

  17. Sirianni, M. et al. The photometric performance and calibration of the HST advanced camera for surveys. Publ. Astron. Soc. Pacif. (in the press); preprint at (2005)

  18. 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 

  19. Frail, D. A. et al. Beaming in gamma-ray bursts: evidence for a standard energy reservoir. Astrophys. J. 562, L55–L58 (2001)

    Article  ADS  Google Scholar 

  20. Rhoads, J. E. The dynamics and light curves of beamed gamma-ray burst afterglows. Astrophys. J. 525, 737–749 (1999)

    Article  ADS  Google Scholar 

  21. Berger, E. et al. A merger origin for short gamma-ray bursts inferred from the afterglow and host galaxy of GRB 050724. Nature (submitted); preprint at (2005)

  22. Kumar, P. The distribution of burst energy and shock parameters for gamma-ray bursts. Astrophys. J. 538, L125–L128 (2000)

    Article  ADS  Google Scholar 

  23. Berger, E., Kulkarni, S. R. & Frail, D. A. A standard kinetic energy reservoir in gamma-ray burst afterglows. Astrophys. J. 590, 379–385 (2003)

    Article  ADS  Google Scholar 

  24. Janka, H.-T. & Ruffert, M. Stellar Collisions, Mergers and their Consequences 333–358 (ASP Conf. Ser. 263, Astronomical Society of the Pacific, San Francisco, 2002)

    Google Scholar 

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

    Article  ADS  Google Scholar 

  26. Totani, T. Probing the cosmic star formation history by the brightness distribution of gamma-ray bursts. Astrophys. J. 511, 41–55 (1999)

    Article  ADS  Google Scholar 

  27. Balázs, L. G., Bagoly, Z., Horváth, I., Mészáros, A. & Mészáros, P. On the difference between the short and long gamma-ray bursts. Astron. Astrophys. 401, 129–140 (2003)

    Article  ADS  Google Scholar 

  28. Katz, J. I. & Canel, L. M. The long and the short of gamma-ray bursts. Astrophys. J 471, 915–920 (1996)

    Article  ADS  Google Scholar 

  29. Piran, T. Compact Stars in Binaries 489–500 (IAU Symp. 165, Kluwer Academic, Dordrecht, 1996)

    Book  Google Scholar 

  30. Eisenstein, D. J., Hogg, D. W. & Padmanabhan, N. GRB050509b, SDSS pre-burst observations. GRB Circ. Netw. 3418 (2005)

  31. Mannucci, F. et al. The supernova rate per unit mass. Astron. Astrophys. 433, 807–814 (2005)

    Article  ADS  CAS  Google Scholar 

  32. Kulkarni, S. R. et al. Radio emission from the unusual supernova 1998bw and its association with the gamma-ray burst of 25 April 1998. Nature 395, 663–669 (1998)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  34. 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 

  35. 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 

  36. Hjorth, J. et al. GRB 050509B: constraints on short gamma-ray burst models. Astrophys. J. Lett. 630, 117–120 (2005)

    Article  ADS  Google Scholar 

  37. Narayan, R., Paczynski, B. & Piran, T. Gamma-ray bursts as the death throes of massive binary stars. Astrophys. J. 395, L83–L86 (1992)

    Article  ADS  CAS  Google Scholar 

  38. Morgan, A. et al. GRB 050709: Swift UVOT and XRT observations. CGN Circ. 3577 (2005)

  39. Schlegel, D. J., Finkbeiner, D. P. & Davis, M. Maps of dust infrared emission for use in estimation of reddening and cosmic microwave background radiation foregrounds. Astrophys. J. 500, 525–553 (1998)

    Article  ADS  Google Scholar 

  40. Motohara, K. et al. CISCO: cooled infrared spectrograph and camera for OHS on the Subaru telescope. Proc. Astron. Soc. Jpn. 54, 315–325 (2002)

    Article  ADS  CAS  Google Scholar 

  41. Fruchter, A. S. & Hook, R. N. Drizzle: a method for the linear reconstruction of undersampled images. Publ. Astron. Soc. Pacif. 114, 144–152 (2002)

    Article  ADS  Google Scholar 

  42. Covino, S. et al. GRB 050724: a short-burst detected by Swift. GCN Circ. 3665 (2005)

  43. Peng, C. Y., Ho, L. C., Impey, C. D. & Rix, H.-W. Detailed structural decomposition of galaxy images. Astron. J. 124, 266–293 (2002)

    Article  ADS  Google Scholar 

  44. Berger, E. et al. A common origin for cosmic explosions inferred from calorimetry of GRB030329. Nature 426, 154–157 (2003)

    Article  ADS  CAS  PubMed  Google Scholar 

  45. Friedman, A. S. & Bloom, J. S. Toward a more standardized candle using gamma-ray burst energetics and spectra. Astrophys. J. 627, 1–25 (2005)

    Article  ADS  CAS  Google Scholar 

  46. Berger, E. et al. The afterglows, redshifts, and properties of Swift gamma-ray bursts. Astrophys. J. (submitted); preprint at (2005)

Download references


Our GRB research is supported in part by funds from NSF, NASA, the Australian Research Council, and the Ministry of Education, Science, Culture, Sports, and Technology in Japan. The VLA is operated by the National Radio Astronomy Observatory, a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership. This work is based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Author information

Authors and Affiliations


Corresponding authors

Correspondence to D. B. Fox or D. A. Frail.

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

Fox, D., Frail, D., Price, P. et al. The afterglow of GRB 050709 and the nature of the short-hard γ-ray bursts. Nature 437, 845–850 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:


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