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An Energetic Afterglow from a Distant Stellar Explosion

Frail, D. A. and Cameron, P. B. and Kasliwal, M. and Nakar, E. and Price, P. A. and Berger, E. and Gal-Yam, A. and Kulkarni, S. R. and Fox, D. B. and Soderberg, A. M. and Schmidt, B. P. and Ofek, E. and Cenko, S. B. (2006) An Energetic Afterglow from a Distant Stellar Explosion. Astrophysical Journal, 646 (2). L99-L102. ISSN 0004-637X.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kasliwal, M.0000-0002-5619-4938
Nakar, E.0000-0002-4534-7089
Berger, E.0000-0002-9392-9681
Gal-Yam, A.0000-0002-3653-5598
Kulkarni, S. R.0000-0001-5390-8563
Fox, D. B.0000-0002-3714-672X
Schmidt, B. P.0000-0001-6589-1287
Ofek, E.0000-0002-6786-8774
Cenko, S. B.0000-0003-1673-970X
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.
Funding AgencyGrant Number
Subject Keywords:cosmology: observations—gamma rays: bursts—radio continuum: general
Issue or Number:2
Record Number:CaltechAUTHORS:FRAapjl06a
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12738
Deposited By: Archive Administrator
Deposited On:22 Dec 2008 17:28
Last Modified:20 Nov 2019 22:47

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