GRB 090426: The Environment of a Rest-Frame 0.35-second Gamma-Ray Burst at Redshift z=2.609 - Astrophysics > High Energy Astrophysical PhenomenaReportar como inadecuado




GRB 090426: The Environment of a Rest-Frame 0.35-second Gamma-Ray Burst at Redshift z=2.609 - Astrophysics > High Energy Astrophysical Phenomena - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We present the discovery of an absorption-line redshift of z = 2.609 for GRB090426, establishing the first firm lower limit to a redshift for a gamma-rayburst with an observed duration of <2 s. With a rest-frame burst duration ofT 90z = 0.35 s and a detailed examination of the peak energy of the event, wesuggest that this is likely at >90% confidence a member of the short-hardphenomenological class of GRBs. From analysis of the optical-afterglow spectrumwe find that the burst originated along a very low HI column density sightline,with N HI < 3.2 x 10^19 cm^-2. Our GRB 090426 afterglow spectrum also appearsto have weaker low-ionisation absorption Si II, C II than ~95% of previousafterglow spectra. Finally, we also report the discovery of a blue, veryluminous, star-forming putative host galaxy ~2 L* at a small angular offsetfrom the location of the optical afterglow. We consider the implications ofthis unique GRB in the context of burst duration classification and ourunderstanding of GRB progenitor scenarios.



Autor: Emily M. Levesque, Joshua S. Bloom, Nathaniel R. Butler, Daniel A. Perley, S. Bradley Cenko, J. Xavier Prochaska, Lisa J. Kewley,

Fuente: https://arxiv.org/







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