Do Lensing Statistics Rule Out a Cosmological Constant?

We present new calculations of gravitational lensing statistics in view of recent revisions in our knowledge of the luminosity function and internal velocity dispersion of E/S0 galaxies that work as effective lenses for background high-redshift QSOs. We show that the theoretical prediction of the lensing statistics is much smaller than previously expected. In sharp contrast to earlier statistics supporting an Ω0 = 1 universe, the small lensing probability reported from the Hubble Space Telescope (HST) Snapshot Lens Survey is in best agreement with a low-density, flat universe with Ω0 ≃ 0.2 and Ω0 + λ0 = 1. The age of this universe, combined with the HST measurement of a high value for the Hubble constant H0, can be reconciled with the age of the oldest globular clusters in the Milky Way.

[1]  C. Kochanek.  Is there a cosmological constant , 1995, astro-ph/9510077.

[2]  R. Bender,et al.  New Light on Galaxy Evolution , 1996 .

[3]  A. Jaunsen,et al.  Gravitational Lenses among Highly Luminous Quasars: Large Optical Surveys , 1996 .

[4]  S. Driver,et al.  The Contribution of Late-Type/Irregulars to the Faint Galaxy Counts from Hubble Space Telescope Medium-Deep Survey Images , 1995, astro-ph/9511123.

[5]  C. Hogan,et al.  Conflict over the age of the Universe , 1995, Nature.

[6]  B. Peterson,et al.  Interpretation of the Faint Galaxy Number Counts in the K Band , 1995 .

[7]  Paul J. Steinhardt,et al.  The observational case for a low-density Universe with a non-zero cosmological constant , 1995, Nature.

[8]  C. Kochanek.  The dynamics of luminous galaxies in isothermal halos , 1994 .

[9]  Garth D. Illingworth,et al.  Distance to the Virgo cluster galaxy M100 from Hubble Space Telescope observations of Cepheids , 1994, Nature.

[10]  J. Huchra,et al.  The Luminosity function for different morphological types in the CfA redshift survey , 1994 .

[11]  S. Driver,et al.  Multicolour faint galaxy number counts with the Hitchhiker parallel CCD camera , 1994 .

[12]  H. Rix,et al.  Early type galaxies, dark halos, and gravitational lensing statistics , 1993 .

[13]  S. Djorgovski,et al.  The Hubble Space Telescope Snapshot Survey. IV - A summary of the search for gravitationally lensed quasars , 1993 .

[14]  R. Narayan,et al.  The influence of core radius on gravitational lensing by elliptical lenses , 1993 .

[15]  K. Kellermann.  The cosmological deceleration parameter estimated from the angular-size/redshift relation for compact radio sources , 1993, Nature.

[16]  S. Maddox,et al.  The Stromlo-APM redshift survey. I: The luminosity function and space density of galaxies , 1992 .

[17]  J. Mould,et al.  Internal dynamics of the dwarf elliptical NGC 185 , 1992 .

[18]  M. Fukugita,et al.  Gravitational lensing frequencies: galaxy cross-sections and selection effects , 1991 .

[19]  H. Ferguson,et al.  Population Studies in Groups and Clusters of Galaxies. IV. Comparison of the Luminosity Functions and Morphological-Type Distributions in Seven Nearby Groups , 1991 .

[20]  S. Maddox,et al.  The cosmological constant and cold dark matter , 1990, Nature.

[21]  Richard S. Ellis,et al.  Analysis of a complete galaxy redshift survey – II. The field-galaxy luminosity function , 1988 .

[22]  G. Hinshaw,et al.  Gravitational Lensing by Isothermal Spheres with Finite Core Radii: Galaxies and Dark Matter , 1987 .

[23]  A. Sandage,et al.  Studies of the Virgo Cluster. 5. Luminosity Functions of Virgo Cluster Galaxies , 1985 .

[24]  J. Gott,et al.  The Statistics of gravitational lenses: The Distributions of image angular separations and lens redshifts , 1984 .

[25]  M. Postman,et al.  The morphology-density relation - The group connection , 1984 .

[26]  G. Vaucouleurs,et al.  The central velocity dispersion in elliptical and lenticular galaxies as an extragalactic distance indicator , 1982 .

[27]  E. Hubble.  The Luminosity Function of Nebulae. I. The Luminosity Function of Resolved Nebulae as Indicated by Their Brightest Stars , 1936 .