Galaxy Mergers and Gravitational Lens Statistics

Abstract

We investigate the impact of hierarchical galaxy merging on the statistics of gravitational lensing of distant sources. Since no definite theoretical predictions for the merging history of luminous galaxies exist, we adopt a parametrized prescription, which allows us to adjust the expected number of pieces comprising a typical present galaxy at z=0.65. The existence of global parameter relations for elliptical galaxies and constraints on the evolution of the phase space density in dissipationless mergers, allow us to limit the possible evolution of galaxy lens properties under merging. We draw two lessons from implementing this lens evolution into statistical lens calculations: (1) The total optical depth to multiple imaging (e.g. of quasars) is quite insensitive to merging. (2) Merging leads to a smaller mean separation of observed multiple images. Because merging does not reduce drastically the expected lensing frequency it cannot make $\lambda$-dominated cosmologies compatible with the existing lensing observations. A comparison with the data from the HST Snapshot Survey shows that models with little or no evolution of the lens population are statistically favored over strong merging scenarios. The specific merging scenario proposed by Toomre (1977) can be rejected (95\% level) by such a comparison. Some versions of the scenario proposed by Broadhurst, Ellis \& Glazebrook (1992), are statistically acceptable.

uuencoded postscript file with figures

Cited by in corpus (29)

• Limits on Cosmological Models From Radio-Selected Gravitational Lenses
• The Fundamental Plane of Gravitational Lens Galaxies and The Evolution of Early-Type Galaxies in Low Density Environments
• On the Size and Comoving Mass Density Evolution of Early-Type Galaxies
• Improved Cosmological Constraints from Gravitational Lens Statistics
• The Evolution and Structure of Early-type Field Galaxies: A Combined Statistical Analysis of Gravitational Lenses
• The Evolution of a Mass-Selected Sample of Early-Type Field Galaxies
• The redshift distribution of gravitational lenses revisited: Constraints on galaxy mass evolution
• Expected constraints on the generalized Chaplygin equation of state from future supernova experiments and gravitational lensing statistics
• Global Probes of the Impact of Baryons on Dark Matter Halos
• A survey for large image-separation lensed quasars
• What Fraction of Gravitational Lens Galaxies Lie in Groups?
• Constraints on cosmological models from lens redshift data
• Effects of Ellipticity and Shear on Gravitational Lens Statistics
• $f(R)$ gravity theories in the Palatini Formalism constrained from strong lensing
• Limits on the evolution of galaxies from the statistics of gravitational lenses
• Quasar Clustering and Spacetime Geometry
• Effects of Disks on Gravitational Lensing by Spiral Galaxies
• A Close Separation Double Quasar Lensed by a Gas-Rich Galaxy
• Curvature of the Universe and Observed Gravitational Lens Image Separations Versus Redshift
• Constraints on the Cardassian Expansion from the Cosmic Lens All-Sky Survey Gravitational Lens Statistics
• Effects of Dust on Gravitational Lensing by Spiral Galaxies
• Q1208+1011: Search for the lensing galaxy
• Gravitational lensing by elliptical galaxies
• Quasar-galaxy associations from gravitational lensing: revisited
• Constraints On Galaxy Evolution Through Gravitational Lensing Statistics
• Microlensing of Quasars By Stars In Their Damped Lyman alpha Absorbers
• Detection of an ultra-bright submillimeter galaxy behind the Small Magellanic Cloud
• Gravitational lenses in the dark Universe
• Gravitational Lensing Bound On The Average Redshift Of Gamma Ray Bursts In Models With Evolving Lenses