Lyman-alpha absorbers arising in galaxy clusters
| dc.creator | Ortiz-Gil, A. | |
| dc.creator | Lanzetta, K. M. | |
| dc.creator | Webb, J. K. | |
| dc.creator | Barcons, X. | |
| dc.date | 1997-09-15 | |
| dc.date.accessioned | 2026-07-07T02:24:14Z | |
| dc.date.available | 2026-07-07T02:24:14Z | |
| dc.description | We present here new GHRS observations of Lyman-alpha absorption lines associated with groups or clusters toward the QSOs 1545+2101 and 0850+4400. In the first case we have identified at least eight distinct Lyman-alpha absorption features, with a mean redshift of <z> = 0.2648 \pm 0.0002 and a velocity dispersion of 163 \pm 57 km/s. We have also identified a group or cluster of galaxies in the vicinity of this QSO with a mean redshift of <z> = 0.2643 \pm 0.0004 and velocity dispersion 223 \pm 91 km/s . The spectrum of QSO 0850+4400, of poorer quality, reveals two Lyman-alpha absorption features at z=0.0909500 \pm 0.0000070 (which is just resolved) and z=0.0948215 \pm 0.0000090, separated by $\sim 1060 km/s. A group or cluster of galaxies is also present in the vicinity of the QSO line-of-sight with a mean redshift <z>=0.0901 \pm 0.0007 and velocity dispersion of 530 \pm 200 km/s. The results of this work establish that Lyman-alpha absorption can occur in denser than average galaxy environments, and that it arises in discrete objects spanning a velocity range similar to that of the cluster galaxies. Although a one-to-one relationship between absorbers and galaxies is difficult to establish in such a dense environment, the results obtained here are indeed consistent with the Lyman-alpha absorption lines being associated with individual galaxies also in groups and clusters. Moreover, the data shows clearly that line clustering takes place in the Lyman-alpha forest. | |
| dc.description | 2 pages, 2 figures, to appear in the proceedings of the 13th IAP Conference on "Evolution of the Intergalactic Medium From QSO Absorption Line Systems" | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9709136 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9709136 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/11542 | |
| dc.subject | Astrophysics | |
| dc.title | Lyman-alpha absorbers arising in galaxy clusters | |
| dc.type | text |