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Optical and Radio Observations of the Afterglow from GRB 990510: Evidence for a Jet

Harrison, F. A. and Bloom, J. S. and Frail, D. A. and Sari, P. and Kulkarni, S. R. and Djorgovski, S. G. and Axelrod, T. and Mould, J. and Schmidt, B. P. and Wieringa, M. H. and Wark, R. M. and Subrahmanyan, R. and McConnell, D. and McCarthy, P. J. and Schaefer, B. E. and McMahon, R. G. and Markze, R. O. and Firth, E. and Soffitta, P. and Amati, L. (1999) Optical and Radio Observations of the Afterglow from GRB 990510: Evidence for a Jet. Astrophysical Journal, 523 (2). L121-L124. ISSN 0004-637X. doi:10.1086/312282.

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We present multicolor optical and two-frequency radio observations of the bright BeppoSAX event GRB 990510. Neither the well-sampled optical decay nor the radio observations are consistent with simple spherical afterglow models. The achromatic steepening in the optical band and the early decay of the radio afterglow, which both occur at t ~ 1 day, are evidence for hydrodynamical evolution of the source and can be most easily interpreted by models in which the gamma-ray burst ejecta are collimated in a jet. Employing a simple jet model to explain the observations, we derive a jet opening angle of θ_0 = 0.08(n/1 cm^(-3))^(1/8), reducing the isotropic gamma-ray energy release of 2.9 × 10^(53) ergs by a factor of ~300.

Item Type:Article
Related URLs:
URLURL TypeDescription
Harrison, F. A.0000-0003-2992-8024
Bloom, J. S.0000-0002-7777-216X
Kulkarni, S. R.0000-0001-5390-8563
Djorgovski, S. G.0000-0002-0603-3087
Mould, J.0000-0003-3820-1740
Schmidt, B. P.0000-0001-6589-1287
Soffitta, P.0000-0003-1252-4891
Additional Information:© 1999. The American Astronomical Society. Received 1999 July 12; accepted 1999 August 2; published 1999 September 7. We thank Scott Barthelmy for operating the GCN, the staffs of LCO, MSSSO, and ATCA, and the entire BeppoSAX team. This work was supported by grants from NSF (S. R. K. and S. G. D.), NASA (F. A. H. and S. R. K.), and the Bressler Foundation (S. G. D.).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Bressler FoundationUNSPECIFIED
Subject Keywords:cosmology: miscellaneous; gamma rays: bursts; radio continuum: general; shock waves
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1999-59
Issue or Number:2
Record Number:CaltechAUTHORS:20150218-142510130
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54953
Deposited By: Deborah Miles
Deposited On:25 Feb 2015 00:22
Last Modified:10 Nov 2021 20:39

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