Founded by merging of the Institut für Astrophysik und Extraterrestrische Forschung, the Sternwarte and the Radioastronomisches Intitut der Universität Bonn.
Absorption features of high-redshift galactic winds
Article first published online: 26 SEP 2007
Monthly Notices of the Royal Astronomical Society
Volume 381, Issue 2, pages 469–488, October 2007
How to Cite
Fangano, A. P. M., Ferrara, A. and Richter, P. (2007), Absorption features of high-redshift galactic winds. Monthly Notices of the Royal Astronomical Society, 381: 469–488. doi: 10.1111/j.1365-2966.2007.12220.x
- Issue published online: 26 SEP 2007
- Article first published online: 26 SEP 2007
- Accepted 2007 July 10. Received 2007 July 4; in original form 2007 April 14
- galaxies: formation;
- intergalactic medium;
- cosmology: theory;
- large-scale structure of Universe
The environment of high-redshift galaxies is characterized by both wind-driven outflowing gas and gravitationally infalling streams. To investigate such galaxy–IGM interplay we have generated synthetic optical absorption line spectra piercing the volume surrounding a starbursting analogue of a Lyman-break galaxy selected in a z≈ 3 output from a smoothed particle hydrodynamics simulation, including a detailed treatment of mechanical feedback from winds. Distributions for several observable species (H i, C iii, C iv, Si ii, Si iii, Si iv, O vi, O vii and O viii) have been derived by post-processing the simulation outputs. The hot-wind material is characterized by the presence of high-ionization species such as O vi, O vii and O viii (the latter two observable only in X-ray bands); the colder (T < 105.5 K) infalling streams can be instead identified by the combined presence of Si ii, Si iii and C iii optical absorption together with O vi that surrounds the cooler gas clumps. However, both line profile and pixel optical depth analysis of the synthetic spectra show that the intergalactic filament in which the wind-blowing galaxy is embedded produces absorption signatures that closely mimic those of the wind environment. We conclude that it may be difficult to clearly identify wind-blowing galaxies and their complex gaseous environment at high redshift in optical QSO absorption-line spectra based solely on the observed ion-absorption patterns.