Absorption Spectrum of the Z = 3.78 QSO 2000-330. I. The Lyman-Alpha Forest Region at 1.5 Angstrom Resolution
Abstract
Spectra of the z = 3.78 QSO 2000-330 have been obtained at the Anglo-Australian Telescope with a resolution of ∼ 1.5 Å FWHM. The region covered, 4100-5900 Å, extends from blueward of a cutoff at 4150 Å to the red wing of Lyα. Structure in the profile of Lyα emission suggests the presence of Si III λ 1206, the first time this line has been seen in emission in a QSO. 280 absorption lines are listed, and identifications are made in 45 Lyman-series systems and four heavy-element systems, the latter systems ranging in redshift from zabs = 3.1881 to 3.5519. The zabs = 3.1881 system is unusual in being purely low ionization, with no detectable Si IV or C IV. For this system we estimate [O/H] > -1.1 dex relative to solar, indicating an oxygen abundance at this early epoch that is surprisingly close to values typical of neutral interstellar clouds in the Galactic disk. The mean density of Lyoc absorption lines in 2000-330 has been compared with published values at lower redshift. We find a significant increase in line density (3.3σ for q0 = 0, 4.3 σ for q0 = 1/2) between < z > = 1.83 and 3.41.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1986
- DOI:
- 10.1086/164262
- Bibcode:
- 1986ApJ...305..496H
- Keywords:
-
- Absorption Spectra;
- Abundance;
- Astronomical Catalogs;
- Astronomical Spectroscopy;
- Lyman Alpha Radiation;
- Quasars;
- Continuous Spectra;
- Emission Spectra;
- Line Spectra;
- Milky Way Galaxy;
- Molecular Clouds;
- Red Shift;
- Spectral Resolution;
- Ultraviolet Spectra;
- Astrophysics;
- ABUNDANCES;
- LINE IDENTIFICATIONS;
- QUASARS