Gas and dust properties in the afterglow spectra of GRB 050730

Starling, R. L. C.; Vreeswijk, P. M.; Ellison, S. L.; Rol, E.; Wiersema, K.; Levan, A. J.; Tanvir, N. R.; Wijers, R. A. M. J.; Tadhunter, C.; Rodriguez Zaurin, J.; Gonzalez Delgado, R. M.; Kouveliotou, C.
Referencia bibliográfica

Astronomy and Astrophysics, Volume 442, Issue 2, November I 2005, pp.L21-L24

Fecha de publicación:
11
2005
Número de autores
12
Número de autores del IAC
0
Número de citas
75
Número de citas referidas
70
Descripción
We present early WHT ISIS optical spectroscopy of the afterglow of gamma-ray burst GRB 050730. The spectrum shows a DLA system with the highest measured hydrogen column to date: N(H I) = 22.1 ± 0.1 at the third-highest GRB redshift z = 3.968. Our analysis of the Swift XRT X-ray observations of the early afterglow show X-ray flares accompanied by decreasing X-ray absorption. From both the optical and the X-ray spectra we constrain the dust and gas properties of the host galaxy. We find the host to be a low metallicity galaxy, with low dust content. Much of the X-ray absorbing gas is situated close to the GRB, whilst the H I absorption causing the DLA is most likely located further out.