Publications of the Astronomical Society of the Pacific
106: 1052-1067, 1994 October


The Search for Primeval Galaxies

C. J. Pritchet

Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, MS 7700, Victoria, BC, Canada V8W 3P6
Electronic mail: pritchet@clam.phys.uvic.ca


ABSTRACT. Isolated examples of young star-forming galaxies have been discovered, but the predicted widespread population of primeval galaxies (estimated to have surface densities in the range 104-5 deg-2) has so far escaped detection. The search for this extensive (and, so far, elusive) population concerns the formation of spheroidal systems (bulges and halos) since there is considerable evidence that disk formation was more quiescent. The review begins with a summary of the expected model independent properties of primeval galaxies. Particular attention is paid to the redshift of galaxy formation; empirical evidence is presented that supports galaxy formation at z < 5; however, there exist persuasive arguments that at least some galaxy formation must have taken place at higher redshifts. A major part of this review concerns primeval galaxy search strategies. Most (although not all) constraints on the properties of primeval galaxies come from searches for Lyman-alpha-emitting objects. Flux limits for these searches have now reached levels at which surveys should, according to simple models, have detected a total of 101-3 objects; yet no really good candidates have been found. This discrepancy between models and observations can possibly be explained by a combination of (i) dust absorption, and (ii) finite angular extent, which degrades flux limits. Technological advances in sub-mm instrumentation should result in the detection of the far-IR flux of primeval galaxies in the next few years.


Keywords: cosmology - galaxies: evolution - galaxies: formation


Table of Contents

INTRODUCTION

PROPERTIES OF PRIMEVAL GALAXIES
Surface Density
Spectrum
Luminosity
Size and Morphology
Redshift of Galaxy Formation
Primeval Galaxy Candidates

MODELS OF PRIMEVAL GALAXIES

PRIMEVAL GALAXY SEARCH STRATEGIES
Some Boradband Searches
Quasars and PG Searches
Redshift Surveys
Searches for Redshifted 21 cm Radiation from Neutral Hydrogen
Searches for UV-Optical Emission Lines

COMPLICATIONS
Dust
Angular Extent
Other Complications
Revised Comparison of Observational Limits with Models

THE FUTURE
UV/Optical/IR Surveys
Millimeter and Submillimeter Surveys

REFERENCES

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