Gravitational lensing statistics based on a large sample of highly luminous quasars

We re-analyze constraints on the cosmological constant that can be obtained by examining the statistics of strong gravitational lensing of distant quasars by intervening galaxies, focusing on uncertainties in galaxy models (including velocity dispersion, luminosity functions, core radii and magnification bias effects) and on the parameters of the galaxy distribution and luminosity functions. In the process we derive new results on magnification biasing for galaxy lenses with nonzero core radii, and on how to infer the proper velocity dispersions appropriate for use in lensing statistics. We argue that the existing data do not disfavor a large cosmological constant. In fact, for a set of reasonable parameter choices, using the results of 5 optical quasar lensing surveys we find that a maximum likelihood analysis favors a value of Ω o in the range ≈ 0.25-0.55 in a flat universe. An open cosmology is not favored by the same statistical analysis. Systematic uncertainties are likely to be dominant, however, as these results are sensitive to uncertainties in our understanding of galaxy luminosity functions, and dark matter velocity dispersions, as well as the choice of lensing survey, and to a lesser extent the existence of core radii. Further observational work will be required before it is possible to definitively distinguish between cosmological models on the basis of gravitational lensing statistics.

show abstract

“…We choose σ * DM = 203 km s −1 , r * c = 45h −1 pc, and γ = 2.83. . [29], Surdej et al [31], and Yee et al [32]. Four lensing events are used.…”

Section: Discussionmentioning

confidence: 99%

“…z l = 1.438 in system H1413+117 and z l = 1.1349 in system Q1208+1011 are generally used, unless otherwise noted. [30], Maoz et al [29], Surdej et al [31], and Yee et al [32]. Four lensing events are used.…”

Section: Discussionmentioning

confidence: 99%

Gravitational Lensing Statistics and Constraints on the Cosmological Constant Revisited

Cheng

Krauss

2000

Int. J. Mod. Phys. A

View full text Add to dashboard Cite

show abstract

“…There have been several systematic surveys for examples of multiple-image gravitational lensing of extragalactic sources, at both optical wavelengths (e.g., Maoz et al 1993;Surdej et al 1993;Gregg et al 2001) and radio wavelengths (Burke et al 1993;King et al 1999;Winn et al 2000;Browne & Myers 2002). The interpretation of the number of lensed sources that are detected in a flux-limited survey depends critically on the factors by which the sources are magnified.…”

Section: Introductionmentioning

confidence: 99%

Analytic Expressions for Mean Magnification by a Quadrupole Gravitational Lens

Finch

Carlivati²,

Winn

et al. 2002

ApJ

View full text Add to dashboard Cite

We derive an analytic expression for the mean magnification due to strong gravitational lensing, using a simple lens model: a singular isothermal sphere embedded in an external shear field. We compute separate expressions for two-image and four-image lensing. For four-image lensing, the mean magnification takes a particularly simple form:, where is the external shear. We compare our analytic results with a numerical evaluation of the full magnification distribution. The results can be used to understand the magnification bias that favors the discovery of four-image systems over two-image systems in fluxlimited lens surveys.

show abstract

“…Previous observations of HLQs have been conducted at ESO (Surdej et al 1993a), with HST (Maoz et al 1993), the CFHT (Crampton et al 1992, Yee et al 1993, and with the NOT (Jaunsen et al 1995). The statistics of the merged sample has been improved by the observation of new HLQs, carried out with the NOT and at ESO, and by a careful re-analysis of the HST frames (see Surdej et al in these proceedings).…”

Section: Survey Samplementioning

confidence: 99%

“…This technique has proven to be very efficient in order to find new gravitational lenses (GLs) (Turner et al 1984, Surdej et al 1987,1988,1993a. Today, the large number of observed HLQs also allows us to perform meaningful maximum likelihood analyses to constrain the parameter values of the lens and of the cosmological models.…”

Section: Introductionmentioning

confidence: 99%

Gravitational Lenses Among Highly Luminous Quasars: Large Optical Surveys

Claeskens

Jaunsen

Surdej³

1996

Symp. - Int. Astron. Union

Self Cite

View full text Add to dashboard Cite

Abstract. The search for multiply imaged quasars among highly luminous quasars (HLQs) is a very good strategy to determine the fundamental parameters of the Universe. We report on the present observational status of a combined sample of HLQs, including new observations obtained with the Nordic Optical Telescope (NOT) and at ESO. This combined sample of HLQs now contains 1178 distinct HLQs. A complete list of the total sample will be soon made available, through a World-Wide-Web page. Preliminary maximum likelihood results are also presented, using a simple statistical model to constrain the values of galactic parameters, of the number counts of QSOs, and of the cosmological constant.

show abstract

Gravitational lensing statistics based on a large sample of highly luminous quasars

Cited by 50 publications

References 0 publications

Gravitational Lensing Statistics and Constraints on the Cosmological Constant Revisited

Gravitational Lensing Statistics and Constraints on the Cosmological Constant Revisited

Analytic Expressions for Mean Magnification by a Quadrupole Gravitational Lens

Gravitational Lenses Among Highly Luminous Quasars: Large Optical Surveys

Contact Info

Product

Resources

About