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 and elliptical host galaxy of the short γ-ray burst GRB 050724


Despite a rich phenomenology, γ-ray bursts (GRBs) are divided1 into two classes based on their duration and spectral hardness—the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing2 their origin to star-forming galaxies, and hence the death of massive stars, and indicating3 an energy release of about 1051 erg. While theoretical arguments4 suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent5,6,7,8 localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift9 z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10–1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions5,6 and providing support for coalescing compact object binaries as the progenitors.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Near-infrared K -band images of the afterglow and host galaxy of GRB 050724.
Figure 2: Optical spectra of the host galaxy of GRB 050724.
Figure 3: Radio to X-ray spectral energy distribution of the afterglow emission 12 h after the burst.


  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. Pian, E. et al. Hubble Space Telescope Imaging of the optical transient associated with GRB 970508. Astrophys. J. 492, L103–L106 (1998)

    Article  ADS  CAS  Google Scholar 

  3. 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 

  4. 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 

  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. Preprint at (2005).

  6. Gehrels, N. et al. A short γ-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225. Nature 437, 851–854 (2005)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  9. Prochaska, J. X. et al. GRB 050724: secure host redshift from Keck. GCN Circ. 3700 (2005)

  10. Krimm, H. et al. GRB050724: refined analysis of the Swift-BAT possible short bursts. GCN Circ. 3667 (2005)

  11. Barthelmy, S. D. et al. An origin for short γ-ray bursts unassociated with current star formation. Nature doi:10.1038/nature04392 (this issue)

  12. D'Avanzo, P. et al. GRB050724: VLT observations of the variable source. GCN Circ. 3690 (2005)

  13. Bloom, J. S., Dupree, A., Chen, H.-W. & Prochaska, J. X. GRB050724: GMOS imaging and spectroscopy. GCN Circ. 3679 (2005)

  14. Freedman, D. L. & Waxman, E. On the energy of gamma-ray bursts. Astrophys. J. 547, 922–928 (2001)

    Article  ADS  Google Scholar 

  15. 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 

  16. Lithwick, Y. & Sari, R. Lower limits on Lorentz factors in gamma-ray bursts. Astrophys. J. 555, 540–545 (2001)

    Article  ADS  CAS  Google Scholar 

  17. Granot, J. & Sari, R. The shape of spectral breaks in gamma-ray burst afterglows. Astrophys. J. 568, 820–829 (2002)

    Article  ADS  CAS  Google Scholar 

  18. Sari, R., Piran, T. & Halpern, J. P. Jets in gamma-ray bursts. Astrophys. J. 519, L17–L20 (1999)

    Article  ADS  Google Scholar 

  19. Dressler, A. & Gunn, J. E. Spectroscopy of galaxies in distant clusters. II—The population of the 3C 295 cluster. Astrophys. J. 270, 7–19 (1983)

    Article  ADS  CAS  Google Scholar 

  20. 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 

  21. 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 

  22. Fryer, C. L., Woosley, S. E. & Hartmann, D. H. Formation rates of black hole accretion disk gamma-ray bursts. Astrophys. J. 526, 152–177 (1999)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  24. Price, P. A. GRB 050709: spectroscopy. GCN Circ. 3605 (2005)

  25. van den Bergh, S. The frequency of SN IA in galaxies of different Hubble type. Publ. Astron. Soc. Pacif. 102, 1318–1320 (1990)

    Article  ADS  Google Scholar 

  26. Phinney, E. S. The rate of neutron star binary mergers in the universe—Minimal predictions for gravity wave detectors. Astrophys. J. 380, L17–L21 (1991)

    Article  ADS  Google Scholar 

  27. Barris, B. J., Tonry, J. L., Novicki, M. C. & Wood-Vasey, W. M. The NN2 flux difference method for constructing variable object light curves. Preprint at (2005).

  28. Burrows, D. et al. GRB 050724: Chandra observations of the X-ray afterglow. GCN Circ. 3697 (2005)

  29. Cole, S. et al. The 2dF galaxy redshift survey: near-infrared galaxy luminosity functions. Mon. Not. R. Astron. Soc. 326, 255–273 (2001)

    Article  ADS  Google Scholar 

  30. 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 

Download references


We are, as always, indebted to S. Barthelmy and the GCN. GRB research at Carnegie and Caltech is supported in part by funds from NASA. E.B. and A.G.Y. are supported by NASA through Hubble Fellowship grants awarded by the Space Telescope Science Institute, which is operated by AURA, Inc., for NASA. The VLA is operated by the National Radio Astronomy Observatory, a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Author information

Authors and Affiliations


Corresponding author

Correspondence to E. Berger.

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

Berger, E., Price, P., Cenko, S. et al. The afterglow and elliptical host galaxy of the short γ-ray burst GRB 050724. Nature 438, 988–990 (2005).

Download citation

  • Received:

  • Accepted:

  • Published:

  • 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