1997/08/30 by S. G. Djorgovski, Djorgovski, S. G.
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9709001
To appear in: Structure and Evolution of the IGM from QSO Absorption Line Systems, IAP Colloquium, eds. P. Petitjean and S. Charlot, in press; 4 pages, a LaTeX file, two style files, and 2 separate postscript figures
arxiv created 1997/08/30 · openalex publication_date 1997/08/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Our understanding of the nature of DLA systems at large redshifts, ostensibly progenitors of normal disk galaxies, depends critically on their direct identifications with galaxies, and the resulting measurements of their properties. A few such objects have now been found, reaching out to z ~ 4.1. Their observed luminosities are L ~ L_*, star formation rates a few Msun/yr, physical sizes ~ 20 kpc, and velocity fields of a few hundred km/s, implying masses > 1011 Msun. While their morphology remains uncertain, the observed properties are consistent with those expected of young disk galaxies in the early stages of formation. We also find a statistically significant excess of foreground galaxies near lines of sight to luminous quasars at z > 4. This suggests a systematical gravitational lensing magnification of such quasar samples, possibly with important consequences for the estimates of the quasar luminosity function at high redshifts, and the deduced Omegab in DLA systems found in their spectra.