DAMPED Lyα SYSTEMS
نویسندگان
چکیده
Observations of damped Lyα systems offer a unique window on the neutral-gas reservoirs that gave rise to galaxies at high redshifts. This review focuses on critical properties such as the H I and metal content of the gas and on independent evidence for star formation. Together, these provide an emerging picture of gravitationally bound objects in which accretion of gas from the IGM replenishes gas consumed by star formation. Other properties such as dust content, molecular content, ionized-gas content, gas kinematics, and galaxy identifications are also reviewed. These properties point to a multi-phase ISM in which radiative and hydrodynamic feedback processes are present. Numerical simulations and other types of models used to describe damped Lyα systems within the context of galaxy formation are also discussed.
منابع مشابه
PROBING HIGH-REDSHIFT DISKS WITH DAMPED Lyα SYSTEMS
Evidence is presented that the damped Lyα absorption systems are the high-redshift (z > 3) progenitors of galaxy disks. I discuss kinematic evidence that the damped Lyα systems are rotating disks. I also discuss implications of the lack of metal-poor damped Lyα systems with line width ∆v > 100 km s. I then present new evidence stemming from correlations between element-abundance ratios and [Fe/...
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I briefly draw comparisons between the fields of damped Lyα and metal-poor stellar abundances. In particular, I examine their complementary age-metallicity relations and comparisons between the damped Lyα and dwarf galaxy abundance patterns. Regarding the latter, I describe a series of problems concerning associating high z damped Lyα systems with present-day dwarfs.
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We combine predictions for several hierarchical cosmogonies with observational evidence on damped Lyα systems to establish a correspondence between the high redshift galaxy population and the properties of damped Lyα systems (DLAS). We assume that high redshift galaxies and damped Lyα systems are hosted by the same dark matter halos and require consistency between the predicted halo space densi...
متن کاملTHE UCSD HIRES/KECKI DAMPED Lyα ABUNDANCE DATABASE II. THE IMPLICATIONS
We present a comprehensive analysis of the damped Lyα abundance database presented in the first paper of this series. This database provides a homogeneous set of abundance measurements for many elements including Si, Cr, Ni, Zn, Fe, Al, S, Co, O, and Ar from 38 damped Lyα systems with zabs > 1.5. With little exception, these damped Lyα systems exhibit very similar relative abundances. There is ...
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The mean metallicity of the thick disk of the Galaxy is 0.5 dex higher than that of the damped Lyα systems. This has been interpreted to argue that stars in the former do not arise out of gas in the latter. Using new metallicity and H I column-density data we show the metal-rich damped systems do contain sufficient baryons at the thick-disk metallicity to account for the stellar masses of thick...
متن کاملNEW DAMPED Lyα METALLICITIES FROM ESI SPECTROSCOPY OF FIVE PALOMAR SKY SURVEY QUASARS
This paper presents chemical abundance measurements for 12 new z > 3 damped Lyα systems discovered toward five quasars from the Palomar Sky Survey. We determine H I column densities from profile fits to the observed damped Lyα profiles and measure ionic column densities and limits for all observed metal-line transitions. This dataset, acquired with the Echellette Spectrograph and Imager on the ...
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