European Research and Training Network
The Physics of the Intergalactic Medium

Ionization front in an inhomogeneous environment. Courtesy of Tom Abel.
Overview
The intergalactic medium (IGM) is the repository of the dominant
component of ordinary matter in the Universe.
This network seeks a unified description of the large-scale
distribution, thermal and ionization state, chemical composition, and
evolution of the IGM. Over the past 5 years
optical spectroscopy with large ground-based telescopes and
ultraviolet spectroscopy from space have yielded a wealth of
information on the IGM, which is now known to be gaseous, photoionized
and enriched by ejecta from stars, to display
coherent structures many hundreds of kiloparsecs across, and to contain more
than 90% of all baryons. The programme combines observations of the
IGM at ultraviolet, optical, near-infrared, and X-ray frequencies
using the
VLT,
HST,
FUSE,
and
XMM,
with theoretical studies of the physics of
the IGM and forefront simulations of its evolution in the context of
hierarchical structure formation models.

Gas density distribution at high redshift in a numerical simulation. Courtesy of Tom Theuns.
Scientific targets
The activity of the network focusses on the following areas:
| The formation of the first objects. |
| Reionization - the end of the ``Dark Ages'' |
| Large-scale structure in the diffuse IGM |
| Protogalaxy halos, winds, and the metal enrichment of the IGM. |
| Star-forming galaxies and active nuclei - sources of UV and X-ray radiation. |
| Intracluster gas - the IGM at low redshift. |
and it is organized by the following task groups:
| First stars and metal enrichment. |
| Reionization |
| QSO absorption lines - Observations. |
| Large-scale structure in the diffuse IGM. |
| Numerical simulations. |
| Feedback processes in the IGM. |
| Low-redshift IGM and ICM. |

Participating Institutions:
| Institute of Astronomy, University of Cambridge, United Kingdom |
| MPA fur Astrophysik, Garching, Germany |
| Institut d'Astrophysique de Paris, France |
| European Southern Observatory, Garching, Germany |
| University of Durham, United Kingdom |
| Sterrewacht Leiden, The Netherlands |
| Osservatorio Astrofisico di Arcetri, Italy |
| Technion, Israel Institute of Technology, Haifa, Israel |
Related European Networks:
| The Formation and Evolution of Young Stellar Clusters |
| A European Collaboration to Carry Out, Analyze and Follow-up the Infrared Space Observatory Deep Survey |
| The formation and evolution of galaxies |
| Consortium for European Research on Extragalactic surveys |
Page by Matteo Viel; viel@ast.cam.ac.uk.
Last modified: 21/02/2005