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Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997

Metzger, M. R. and Djorgovski, S. G. and Kulkarni, S. R. and Steidel, C. C. and Adelberger, K. L. and Frail, D. A. and Costa, E. and Frontera, F. (1997) Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997. Nature, 387 (6636). pp. 878-880. ISSN 0028-0836.

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Brief, intense bursts of y-rays occur approximately daily from random directions in space, but their origin has remained unknown since their initial detection almost 25 years ago. Arguments based on their observed isotropy and apparent brightness distribution are not sufficient to constrain the location of the bursts to a local or cosmological origin. The recent detection of a counterpart to a y-ray burst at other wavelengths has therefore raised the hope that the sources of these energetic events might soon be revealed. Here we report spectroscopic observations of the possible optical counterpart to the y-ray burst GRB970508. The spectrum is mostly featureless, except for a few prominent absorption lines which we attribute to the presence of an absorption system along the line of sight at redshift z = 0.835. Coupled with the absence of Lyman-α forest features in the spectra, our results imply that the optical transient lies at 0.835 ≾ z ≾ 2.3. If the optical transient is indeed the counterpart of GRB970508, our results provide the first direct limits on the distance to a y-ray burst, confirming that at least some of these events lie at cosmological distances, and are thus highly energetic.

Item Type:Article
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URLURL TypeDescription ReadCube access
Djorgovski, S. G.0000-0002-0603-3087
Kulkarni, S. R.0000-0001-5390-8563
Steidel, C. C.0000-0002-4834-7260
Additional Information:© 1997 Macmillan Publishers Ltd. Received 21 May; accepted 3 June 1997. We thank the BeppoSAX team for their efforts in disseminating information to observers for rapid identification of an optical transient, making this work possible. We thank W. Sargent and M. Pahre for discussions, and the Keck Observatory staff for assistance at the telescope. This work is based on observations obtained at the W. M. Keck Observatory, which is jointly operated by the California Institute of Technology and the University of California. M.R.M. was supported by Caltech; S.R.K. was supported by NASA and NSF; S.G.D. was supported by NSF and the Bressler Foundation; C.C.S. was supported by NSF and the Sloan Foundation.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
Bressler FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Issue or Number:6636
Record Number:CaltechAUTHORS:20130419-091322811
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Official Citation:Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997 878 S. G. Djorgovski, S. R. Kulkarni, C. C. Steidel, K. L. Adelberger, D. A. Frail, E. Costa & F. Frontera Nature 387, 878-880 (26 June 1997)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38032
Deposited By: Ruth Sustaita
Deposited On:23 Apr 2013 16:23
Last Modified:03 Oct 2019 04:53

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