Optical classification of gamma-ray bursts in the Swift era

Alexander J van der Horst, Chryssa Kouveliotou, Neil Gehrels, Evert Rol, Ralph A M J Wijers, John K Cannizzo, Judith Lea Racusin, David N Burrows

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We propose a new method for the classification of optically dark gamma-ray bursts (GRBs), based on the X-ray and optical-to-X-ray spectral indices of GRB afterglows, and utilizing the spectral capabilities of Swift. This method depends less on model assumptions than previous methods, and can be used as a quick diagnostic tool to identify optically sub-luminous bursts. With this method we can also find GRBs that are extremely bright at optical wavelengths. We show that the previously suggested correlation between the optical darkness and the X-ray/gamma-ray brightness is merely an observational selection effect.
Original languageEnglish
Pages (from-to)1087 - 1091
Number of pages5
JournalThe Astrophysical Journal
Issue number2
Publication statusPublished - 2009
Externally publishedYes

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