Tanga, M., Schady, P., Gatto, A., Greiner, J., Krause, M. G. H., Diehl, R., Savaglio, S. and Walch, S. (2016). Soft X-ray absorption excess in gamma-ray burst afterglow spectra: Absorption by turbulent ISM. Astron. Astrophys., 595. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746
Full text not available from this repository.Abstract
Two-thirds of long duration gamma-ray bursts (GRBs) show soft X-ray absorption in excess of the Milky Way. The column densities of metals inferred from UV and optical spectra differ from those derived from soft X-ray spectra, at times by an order of magnitude, with the latter being higher. The origin of the soft X-ray absorption excess observed in GRB X-ray afterglow spectra remains a heavily debated issue, which has resulted in numerous investigations on the effect of hot material both internal and external to the GRB host galaxy on our X-ray afterglow observations. Nevertheless, all models proposed so far have either only been able to account for a subset of our observations (i.e. at z > 2), or they have required fairly extreme conditions to be present within the absorbing material. In this paper, we investigate the absorption of the GRB afterglow by a collisionally ionised and turbulent interstellar medium (ISM). We find that a dense (3 cm(-3)) collisionally ionised ISM could produce UV/optical and soft X-ray absorbing column densities that differ by a factor of 10. However the UV/optical and soft X-ray absorbing column densities for such sightlines are 2-3 orders of magnitude lower in comparison to the GRB afterglow spectra. For those GRBs with a larger soft X-ray excess by up to an order of magnitude, the contribution in absorption from a turbulent ISM as considered here would ease the required conditions of additional absorbing components, such as the GRB circumburst medium and intergalactic medium.
Item Type: | Journal Article | ||||||||||||||||||||||||||||||||||||
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URN: | urn:nbn:de:hbz:38-256715 | ||||||||||||||||||||||||||||||||||||
DOI: | 10.1051/0004-6361/201527961 | ||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | Astron. Astrophys. | ||||||||||||||||||||||||||||||||||||
Volume: | 595 | ||||||||||||||||||||||||||||||||||||
Date: | 2016 | ||||||||||||||||||||||||||||||||||||
Publisher: | EDP SCIENCES S A | ||||||||||||||||||||||||||||||||||||
Place of Publication: | LES ULIS CEDEX A | ||||||||||||||||||||||||||||||||||||
ISSN: | 1432-0746 | ||||||||||||||||||||||||||||||||||||
Language: | English | ||||||||||||||||||||||||||||||||||||
Faculty: | Unspecified | ||||||||||||||||||||||||||||||||||||
Divisions: | Unspecified | ||||||||||||||||||||||||||||||||||||
Subjects: | no entry | ||||||||||||||||||||||||||||||||||||
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Refereed: | Yes | ||||||||||||||||||||||||||||||||||||
URI: | http://kups.ub.uni-koeln.de/id/eprint/25671 |
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