Emission Line Galaxies from CADIS : High Redshift Lyman-Alpha Galaxies and Metal Poor Galaxies at Medium Redshift

In this thesis, metal poor galaxies at 0.4<z<0.7 and Ly-alpha galaxies at z>4.7 have been searched for and investigated in a sample of 600 faint emission line galaxies from four fields of the Calar Alto Deep Imaging Survey (CADIS). Employing an imaging Fabry-Perot interferometer, CADIS detects emission lines in three waveband windows, free of night-sky emission lines, at 700 nm, 820 nm, and 920 nm. Metal poor galaxies at 0.4<z<0.7 have been selected by their high [OIII]5007 / [OII]3727 ratios. Their oxygen abundances, determined by follow-up spectroscopy, indicate that the metallicity-luminosity relation which applies to galaxies in the local universe also holds at z=0.6. Ly-alpha galaxy candidates from the emission line sample, which contains more than 97% of objects at z<1.2 , are selected by the absence of flux below the Lyman limit (B-band ``dropouts''), and the non-detection of secondary emission lines in narrow band filters. For two Ly-alpha candidates, the emission line detected in the Fabry-Perot has been verified spectroscopically. The comparison of number counts of Lyman-alpha galaxies from CADIS with those of other Ly-alpha surveys at z>3 , and with model predictions, indicates that bright Ly-alpha galaxies are so rare beyond z=5 that a non-evolving population can be excluded.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2002

Author dc:creator

• Maier, Christian

Contributors dc:contributor

• Meisenheimer, Klaus

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/3067

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:3067