The low-ion QSO absorption-line systems
Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Ly{alpha} absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Ly{alpha} absorber toward Q1337 + 113 are presented.
- Research Organization:
- Pittsburgh Univ., PA (USA)
- OSTI ID:
- 6864078
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
QUASARS
ABSORPTION SPECTRA
CARBON
COSMIC DUST
COSMIC GASES
ELEMENT ABUNDANCE
HYDROGEN
LIMITING VALUES
LYMAN LINES
MAGNESIUM
RED SHIFT
SPECTROPHOTOMETRY
SPECTROSCOPY
STATISTICS
ABUNDANCE
ALKALINE EARTH METALS
COSMIC RADIO SOURCES
DUSTS
ELEMENTS
FLUIDS
GASES
MATHEMATICS
METALS
NONMETALS
SPECTRA
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources