CaltechAUTHORS
Published August 1, 2006 | Version Published
Journal Article Open

An Energetic Afterglow from a Distant Stellar Explosion

Creators

  • 1. ROR icon National Radio Astronomy Observatory
  • 2. ROR icon Division of Physics
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon University of Hawaii at Manoa
  • 5. ROR icon Carnegie Observatories
  • 6. ROR icon Princeton University
  • 7. ROR icon Pennsylvania State University
  • 8. ROR icon Mount Stromlo Observatory

Abstract

We present the discovery of radio afterglow emission from the high-redshift (z = 6.295) burst GRB 050904. The peak flux density for this burst is similar to typical low-redshift gamma-ray bursts (GRBs). We further show that beyond a redshift of order unity, the flux densities of radio afterglows are largely insensitive to redshift, consistent with predictions. By combining the existing X-ray, near-infrared, and radio measurements, we derive estimates for the kinetic energy and opening angle of the blast wave and for the density of the circumburst medium into which it expands. Both the kinetic and radiated energy indicate that GRB 050904 was an unusually energetic burst (10^52 ergs). More importantly, we are able to make an in situ measurement of the density structure of the circumburst medium. We conclude that GRB 050904 exploded into a constant-density medium with n0 = 680 cm^−3, which is 2 orders of magnitude above the nominal value for low-redshift GRBs. The next generation of centimeter (EVLA) and millimeter radio instruments (ALMA) will be able to routinely detect events such as GRB 050904 and use them to study magnetic fields and the atomic and molecular gas in the high-redshift universe.

Additional Information

© 2006. The American Astronomical Society. Received 2006 April 27; accepted 2006 June 15; published 2006 July 18. D.A.F. wishes to thank B. Clark for his generous allocation of VLA time during the dynamic scheduling tests. [E.B. and A.G.-Y. were] Hubble Fellows.

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Additional details

Identifiers

Eprint ID
12738
Resolver ID
CaltechAUTHORS:FRAapjl06a

Funding

NASA Hubble Fellowship

Dates

Created
2008-12-22
Created from EPrint's datestamp field
Updated
2021-11-08
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Caltech Custom Metadata

Caltech groups
Division of Geological and Planetary Sciences (GPS)