- Authors:
-
- Dietrich, M. ;
- Appenzeller, I. ;
- Hamann, F. ;
- Heidt, J. ;
- Jaeger, K. ;
-
Vestergaard, Marianne
;
Close
0000-0001-9191-9837
Dark Cosmology Centre, Niels Bohr Institute, Faculty of Science, Københavns Universitet - Wagner, S. J.
- DOI:
- 10.1051/0004-6361:20021697
- Abstract:
- We present observations of 11 high redshift quasars ($3.9 \la z \la 5.0$) observed with low spectral resolution in the restframe ultraviolet using FORS 1 at the VLT UT 1. The emission-line fluxes of strong permitted and intercombination ultraviolet emission lines are measured to estimate the chemical composition of the line emitting gas. Comparisons to photoionization calculations indicate gas metallicities in the broad emission line region in the range of solar to several times solar. The average of the mean metallicity of each high-z quasar in this sample is $Z/Z_\odot = 4.3 \pm 0.3$. Assuming a chemical evolution time scale of $\tau_{evol} \simeq 0.5 - 0.8$ Gyrs, we derive a redshift of $z_f \simeq 6 {\rm to} 8$ for the onset of the first major star formation episode (H$_o = 65$ km s$^{-1}$ Mpc$^{-1}$, $\Omega_M = 0.3$, $\Omega_\Lambda = 0.7$), corresponding to an age of the universe of several $10^8$ yrs at this epoch. We note that this epoch is also supposed to be the era of re-ionization of the universe.
- Type:
- Journal article
- Language:
- English
- Published in:
- Astronomy and Astrophysics, 2003, Vol 398, Issue 3, p. 891-899
- Keywords:
- astro-ph
- Main Research Area:
- Science/technology
- Publication Status:
- Published
- Review type:
- Peer Review
- Submission year:
- 2003
- Scientific Level:
- Scientific
- ID:
- 11136726
Checking for on-site access...
