The nature of Lyman-break galaxies

Abstract

Using semi-analytic models of galaxy formation, we investigate the properties of $z\sim 3$ galaxies and compare them with the observed population of Lyman-break galaxies (LBGs). In addition to the usual quiescent mode of star formation, we introduce a physical model for starbursts triggered by galaxy-galaxy interactions. We find that with the merger rate that arises naturally in the CDM-based merging hierarchy, a significant fraction of bright galaxies identified at high redshift ($z \ga 2$) are likely to be low-mass, bursting satellite galaxies. The abundance of LBGs as a function of redshift and the luminosity function of LBGs both appear to be in better agreement with the data when the starburst mode is included, especially when effects of dust extinction are considered. The objects that we identify as LBGs have observable properties including low velocity dispersions that are in good agreement with the available data. In this ``Bursting Satellite'' scenario, quiescent star formation at $z\ga2$ is relatively inefficient and most of the observed LBGs are starbursts triggered by satellite mergers within massive halos. In high-resolution N-body simulations, we find that the most massive dark matter halos cluster at redshift $z\sim 3$ much as the LBGs are observed to do. This is true for both the $\Omega =1$ CHDM model and low-$\Omega$ \LCDM and OCDM models, all of which have fluctuation power spectra $P(k)$ consistent with the distribution of low-redshift galaxies. The Bursting Satellite scenario can resolve the apparent paradox of LBGs that cluster like massive dark matter halos but have narrow linewidths and small stellar masses.

10 pages, latex, including 2 figures, to appear in the Proceedings of the 3rd International Symposium on Sources and Detection of Dark Matter in the Universe (DM98), Feb. 1998, ed. D. Cline

References in corpus (5)

• The Nature of High-Redshift Galaxies
• A Large Structure of Galaxies At Redshift z~3 and its Cosmological Implications
• A Counts-in-Cells Analysis of Lyman-break Galaxies at z~3
• The seeds of rich galaxy clusters in the Universe
• Confronting cold dark matter cosmologies with strong clustering of Lyman break galaxies at $z\sim 3$

Cited by in corpus (19)

• Tidally-Triggered Star Formation in Close Pairs of Galaxies
• Very Extended X-ray and H-alpha Emission in M82: Implications for the Superwind Phenomenon
• The Fundamental Plane of Gravitational Lens Galaxies and The Evolution of Early-Type Galaxies in Low Density Environments
• The Formation of Disk-Bulge-Halo Systems and the Origin of the Hubble Sequence
• Substructure in Dark Halos: Orbital Eccentricities and Dynamical Friction
• Semi-Analytical Models for the Formation of Disk Galaxies: I. Constraints from the Tully-Fisher Relation
• Models for Dusty Lyman alpha Emitters at High Redshift
• Evidence for Multiple Mergers among Ultraluminous IR Galaxies (ULIRGs): Remnants of Compact Groups?
• The Physical Origin of Scale Dependent Bias in Cosmological Simulations
• Ages for Globular Clusters in the Outer Galactic Halo: The Second Parameter Clusters Palomar~3, Palomar~4 and Eridanus
• Time Evolution of Galaxy Formation and Bias in Cosmological Simulations
• The Growth of Central and Satellite Galaxies in Cosmological Smoothed Particle Hydrodynamics Simulations
• Analysis of Star Formation in Galaxy-like Objects
• H alpha emitting galaxies and the star formation rate density at z~0.24
• Constraints from the Hubble Deep Field on High Redshift Quasar Models
• The Evolution of the Galaxy Sizes in the NTT Deep Field: a Comparison with CDM Models
• Formation and evolution of dusty starburst galaxies I. A new method for deriving spectral energy distribution
• X-raying the Star Formation History of the Universe
• Consequences of feedback from early supernovae for disk assembly