TY - JOUR
T1 - Variable Lya sheds light on the environment surrounding GRB 090426
AU - Thöne, Christina
AU - Ugarte Postigo, Antonio de
AU - Fynbo, Johan Peter Uldall
AU - Hjorth, Jens
AU - Malesani, Daniele
AU - Milvang-Jensen, Bo
AU - Roming...[et al.], P.W.A.
PY - 2011/6
Y1 - 2011/6
N2 - Long 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 (~80pc). 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.
AB - Long 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 (~80pc). 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.
U2 - 10.1111/j.1365-2966.2011.18408.x
DO - 10.1111/j.1365-2966.2011.18408.x
M3 - Journal article
SN - 0035-8711
VL - 414
SP - 479
EP - 488
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
IS - 1
ER -