MNRAS-2011-Thöne-479-88.pdf (13.29 MB)
Variable Lyα sheds light on the environment surrounding GRB 090426
journal contribution
posted on 2012-10-24, 09:08 authored by S. Campana, de Ugarte Postigo A., D. Lazzati, J. P. U. Fynbo, J. Hjorth, D. Malesani, B. Milvang-Jensen, L. Christensen, A. J. Levan, M. A. Aloy, P. Jakobsson, E. M. Levesque, P. W. A. Roming, N. R. Tanvir, K. Wiersema, M. Gladders, E. Wuyts, H. DahleLong duration gamma-ray bursts are commonly associated with the deaths of massive stars. Spectroscopic studies using the afterglow as a light source provide a unique opportunity to unveil the medium surrounding it, probing the densest region of their galaxies. This material is usually in a low ionization state and at large distances from the burst site, hence representing the normal interstellar medium in the galaxy. Here we present the case of GRB 090426 at z= 2.609, whose optical spectrum indicates an almost fully ionized medium together with a low column density of neutral hydrogen. For the first time, we also observe variations in the Lyα absorption line. Photoionization modelling shows that we are probing material from the vicinity of the burst (∼80 pc). The host galaxy is a complex of two luminous interacting galaxies, which might suggest that this burst could have occurred in an isolated star-forming region outside its host galaxy created in the interaction of the two galaxies.
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Citation
Monthly Notices of the Royal Astronomical Society , 2011, 414 (1), pp. 479-488Version
- VoR (Version of Record)
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Monthly Notices of the Royal Astronomical SocietyPublisher
Oxford University Press (OUP)issn
0035-8711eissn
1365-2966Copyright date
2011Available date
2012-10-24Publisher DOI
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http://mnras.oxfordjournals.org/content/414/1/479Language
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