CaltechAUTHORS
Published October 1, 1999 | Version Published
Journal Article Open

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

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon National Radio Astronomy Observatory
  • 3. ROR icon Australian National University
  • 4. ROR icon Commonwealth Scientific and Industrial Research Organisation
  • 5. ROR icon Carnegie Institution for Science
  • 6. ROR icon Yale University
  • 7. ROR icon University of Cambridge
  • 8. ROR icon National Research Council

Abstract

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.

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.).

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Additional details

Identifiers

Eprint ID
54953
Resolver ID
CaltechAUTHORS:20150218-142510130

Related works

Describes
http://adsabs.harvard.edu/abs/1999ApJ...523L.121H (URL)

Funding

NSF
NASA
Bressler Foundation

Dates

Created
2015-02-25
Created from EPrint's datestamp field
Updated
2021-11-10
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Space Radiation Laboratory, Division of Geological and Planetary Sciences (GPS)
Other Numbering System Name
Space Radiation Laboratory
Other Numbering System Identifier
1999-59