CaltechAUTHORS
Published March 1, 2001 | Version Published
Journal Article Open

Multicolor Observations of the GRB 000926 Afterglow

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Mount Stromlo Observatory
  • 3. ROR icon University of Pittsburgh
  • 4. ROR icon Goddard Space Flight Center
  • 5. ROR icon National Radio Astronomy Observatory
  • 6. ROR icon Tel Aviv University
  • 7. ROR icon Columbia University
  • 8. ROR icon New Mexico State University
  • 9. ROR icon University of California, Berkeley
  • 10. ROR icon Infrared Processing and Analysis Center

Abstract

We present multicolor light curves of the optical afterglow of gamma-ray burst (GRB) 000926. Beginning ~1.5 days after the burst, the light curves of this GRB steepen measurably. The existence of such achromatic breaks is usually taken to be an important observational signature that the ejecta are not expanding isotropically but rather have a collimated jetlike geometry. If we interpret the data in this context, we derive an opening angle of 5°, which reduces the energy release compared with an isotropic model by a factor of ~275, to 1.7x10^(51) ergs. To fit the data with a simple jet model requires extinction along the line of sight. The derived A_V is in the range 0.11–0.82 mag, depending on the adopted extinction law and whether the electrons giving rise to the optical emission are undergoing synchrotron cooling or not. Since this is in excess of the expected extinction from our Galaxy, we attribute this to the GRB host. We note that this extinction is typical of a galactic disk, and therefore the event likely took place in the disk of its host.

Additional Information

© 2001 The American Astronomical Society. Received 2000 December 13; accepted 2001 January 25; published 2001 February 26. We thank the staff of the Palomar, Keck, MDM, and Wise Observatories and also L. Cowie, A. Barger, R. Ellis, C. Steidel, and B. Madore for their assistance in obtaining observations. We thank E. Mazets and the Konus team for the IPN data. F. A. H. acknowledges support from a Presidential Early Career award. S. R. K., S. G. D., and J. P. H. thank NSF for support of their ground-based GRB programs. K. H. is grateful for Ulysses support under JPL contract 958056 and NEAR support under NAG5-9503.

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Additional details

Identifiers

Eprint ID
55348
Resolver ID
CaltechAUTHORS:20150227-151024707

Related works

Describes
http://adsabs.harvard.edu/abs/2001ApJ...549L...7P (URL)

Funding

JPL
958056
NASA
NAG5-9503
NSF

Dates

Created
2015-03-06
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
2001-11