Constraints on Dark Energy from Strong Gravitational Lensing by Galaxy Clusters

Meneghetti, M.; Baccigalupi, C.; Bartelmann, Matthias; Dolag, K.; Moscardini, L.; Perrotta, F.; Tormen, Giuseppe

doi:10.1017/s1743921305001985

Cited by 6 publications

(2 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of groups have attempted to test cosmological models by comparing lensing probabilities predicted by various cosmological models with those obtained from observations (Turner, Ostriker, & Gott 1984 ;Narayan & White 1988 ;Kochanek 1993Kochanek , 1995Cen et al 1994 ;Wambsganss et al 1995 ;Maoz et al 1997 ;Wambsganss, Cen, & Ostriker 1998 ;Bartelmann et al 1998 ;Mortlock & Webster 2000 ;Porciani & Madau 2000 ;Keeton & Madau 2001). In the statistical study of cosmological gravitational lensing, usually two di †erent approaches are used : one is to study the lensing probability of splitting angles of multiple images (Turner et al 1984 ;Narayan & White 1988 ;Kochanek 1993Kochanek , 1995Cen et al 1994 ;Wambsganss et al 1995Wambsganss et al , 1998Porciani & Madau 2000 ;Keeton & Madau 2001), and the other is to study the lensing probability of the length-to-width ratio of arcs formed by gravitational lensing (Bartelmann & Weiss 1994 ;Bartelmann et al 1998 ;Cooray 1999 ;Kaufmann & Straumann 2000 ;Meneghetti et al 2001). The two approaches reÑect two di †erent aspects of gravitational lensing and are complimentary to each other ; both of them are directly related to observations and deserve detailed investigations.…”

Section: Introductionmentioning

confidence: 99%

Semianalytical Models for Lensing by Dark Halos. I. Splitting Angles

Li¹,

Ostriker²

2002

ApJ

152

View full text Add to dashboard Cite

We use the semianalytical approach to analyze gravitational lensing of remote quasars by foreground dark halos in various cold dark matter (CDM) cosmologies in order to determine the sensitivity of the predictions for probabilities of image separations to the input assumptions regarding the properties of halos and cosmological models. The power spectrum of primordial Ñuctuations is normalized by the cluster abundance constraints. The mass function of dark halos is assumed to be given by the PressSchechter function. The mass density proÐle of dark halos is alternatively taken to be the singular isothermal sphere (SIS), the Navarro-Frenk-White (NFW) proÐle, or the generalized NFW proÐle. The cosmologies being considered include the EinsteinÈde Sitter model (SCDM), the open model (OCDM), and the Ñat "-model (LCDM). As expected, we Ðnd that the lensing probability is extremely sensitive to the mass density proÐle of lenses (dark halos) and somewhat less so to the mean mass density in the universe and the amplitude of primordial Ñuctuations. NFW halos are very much less e †ective in producing multiple images than SIS halos. For NFW lenses, the SCDM model produces fewer lensing events than the OCDM/LCDM models by 2 orders of magnitude. For SIS lenses, the SCDM model produces more lensing events with small splitting angles and fewer lensing events with large splitting angles than the OCDM/LCDM models, which is due to the fact that for large-mass halos, the PressSchechter function is very sensitive to the amplitude of primordial Ñuctuations. In all cases the di †erence between the OCDM model and the LCDM model is not dramatic. None of these models are consistent with current observations : the SIS models predict too many large splitting lenses, while the NFW models predict too few small splitting lenses. Essentially, the observed high ratio of small splitting to large splitting lenses is not predicted correctly. This indicates that there must be at least two populations of halos in the universe : small-mass halos with a steep inner density slope and large-mass halos with a shallow inner density slope. A combination of SIS and NFW halos can reasonably reproduce the current observations if we choose the mass for the transition from SIS to NFW to be D1013 as might M _ , plausibly occur because of baryonic cooling and contraction in lower mass systems. Additionally, there is a tendency for CDM models to have too much power on small scales, i.e., too much mass concentration. From our sensitivity studies it appears that the cures proposed for other apparent difficulties of CDM would help here as well, an example being the warm dark matter variant, which is shown to produce fewer large splitting lenses than the corresponding CDM model by 1 order of magnitude.

show abstract

Section: Introductionmentioning

confidence: 99%

Semianalytical Models for Lensing by Dark Halos. I. Splitting Angles

Li¹,

Ostriker²

2002

ApJ

152

View full text Add to dashboard Cite

show abstract

“…In addition, their abundance can help to constrain cosmological models (Bartelmann et al 1998;Bartelmann et al 2003;Meneghetti et al 2005;Jullo et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Analytic solutions for Navarro-Frenk-White lens models in the strong lensing regime for low characteristic convergences

Dúmet-Montoya

Caminha

Makler

2013

A&A

View full text Add to dashboard Cite

Context. The Navarro-Frenk-White (NFW) density profile is often used to model gravitational lenses. For κ s 0.1 (where κ s is a parameter that defines the normalization of the NFW lens potential) -corresponding to galaxy and galaxy group mass scales -high numerical precision is required to accurately compute several quantities in the strong lensing regime. Aims. We obtain analytic solutions for several lensing quantities for circular NFW models and their elliptical (ENFW) and pseudoelliptical (PNFW) extensions, on the typical scales where gravitational arcs are expected to be formed, in the κ s 0.1 limit, by establishing their domain of validity. Methods. We approximate the deflection angle of the circular NFW model and derive analytic expressions for the convergence and shear for the PNFW and ENFW models. We obtain the constant distortion curves (including the tangential critical curve), which are used to define the domain of validity of the approximations, by employing a figure-of-merit to compare with the exact numerical solutions. We compute the deformation cross section as a further check of the validity of the approximations. Results. We derive analytic solutions for iso-convergence contours and constant distortion curves for the models considered here. We also obtain the deformation cross section, which is given in closed form for the circular NFW model and in terms of a one-dimensional integral for the elliptical ones. In addition, we provide a simple expression for the ellipticity of the iso-convergence contours of the pseudo-elliptical models and the connection of characteristic convergences among the PNFW and ENFW models. Conclusions. We conclude that the set of solutions derived here is generally accurate for κ s 0.1. For low ellipticities, values up to κ s 0.18 are allowed. On the other hand, the mapping among PNFW and the ENFW models is valid up to κ s 0.4. The solutions derived in this work can be used to speed up numerical codes and ensure their accuracy in the low κ s regime, including applications to arc statistics and other strong lensing observables.

show abstract

Gravitational lensing of the CMB by galaxy clusters

Maturi

Bartelmann

Meneghetti

et al. 2005

A&A

View full text Add to dashboard Cite

Abstract. We adapt a non-linear filter proposed by Hu (2001) for detecting lensing of the CMB by large-scale structures to recover surface-density profiles of galaxy clusters from their localised, weak gravitational lensing effect on CMB fields. Shifting the band-pass of the filter to smaller scales, and normalising it such as to reproduce the convergence rather than the deflection angle, we find that the mean density profile of a sample of 100 clusters can be recovered to better than 10% from well within the scale radius to almost the virial radius. The kinetic Sunyaev-Zel'dovich effect is shown to be a negligible source of error. We test the filter applying it to data simulated using the characteristics of the Atacama Cosmology Telescope (ACT), showing that it will be possible to recover mean cluster profiles outside a radius of 1 corresponding to ACT's angular resolution.

show abstract

Constraints on Dark Energy from Strong Gravitational Lensing by Galaxy Clusters

Cited by 6 publications

References 9 publications

Semianalytical Models for Lensing by Dark Halos. I. Splitting Angles

Semianalytical Models for Lensing by Dark Halos. I. Splitting Angles

Analytic solutions for Navarro-Frenk-White lens models in the strong lensing regime for low characteristic convergences

Gravitational lensing of the CMB by galaxy clusters

Contact Info

Product

Resources

About