Strong lensing in Abell 1703: constraints on the slope of the inner dark matter distribution

Limousin, M.; Richard, Johan; Kneib, Jean-Paul; Brink, Henrik; Pelló, R.; Jullo, Eric; Tu, Hong; Sommer–Larsen, Jesper; Egami, Eiichi; Michalowski, M. J.; Cabanac, R.; Stark, Dan

doi:10.1051/0004-6361:200809646

Cited by 104 publications

(130 citation statements)

References 67 publications

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“…The exact numerical value of the inner slope α of the density profile is still being discussed. While NFW originally proposed α = 1.0, other authors argued that steeper profiles with values up to α = 1.5 provide a better fit to observations and numerical simulations (Moore et al 1999;Jing & Suto 2000;Power et al 2003;Navarro et al 2004;Limousin et al 2008). In contrast, recent combined strong-and weak-lensing analyses of selected clusters indicate shallower mass profiles with inner slopes α < 1 (see Newman et al 2011, for instance).…”

Section: Triaxial Gravitational Lensesmentioning

confidence: 99%

The strongest gravitational lenses

Redlich

Bartelmann

Waizmann

et al. 2012

A&A

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For more than a decade now, it has been controversial whether or not the high rate of giant gravitational arcs and the largest observed Einstein radii are consistent with the standard cosmological model. Recent studies indicate that mergers provide an efficient mechanism to substantially increase the strong-lensing efficiency of individual clusters. Based on purely semi-analytic methods, we investigated the statistical impact of cluster mergers on the distribution of the largest Einstein radii and the optical depth for giant gravitational arcs of selected cluster samples. Analysing representative all-sky realizations of clusters at redshifts z < 1 and assuming a constant source redshift of z s = 2.0, we find that mergers increase the number of Einstein radii above 10 (20 ) by ∼35% (∼55%). Exploiting the tight correlation between Einstein radii and lensing cross sections, we infer that the optical depth for giant gravitational arcs with a length-to-width ratio ≥7.5 of those clusters with Einstein radii above 10 (20 ) increases by ∼45% (∼85%). Our findings suggest that cluster mergers significantly influence in particular the statistical lensing properties of the strongest gravitational lenses. We conclude that semi-analytic studies must inevitably take these events into account before questioning the standard cosmological model on the basis of the largest observed Einstein radii and the statistics of giant gravitational arcs.

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Section: Triaxial Gravitational Lensesmentioning

confidence: 99%

The strongest gravitational lenses

Redlich

Bartelmann

Waizmann

et al. 2012

A&A

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“…In general, modelling each perturbing galaxy on its own would allow us to obtain a closer fit to the data (Limousin et al 2008). On the other hand, the cluster-sized DM halo cannot be effectively distinguished from that of the BCG by means of pure lensing analyses 1 .…”

Section: Mass Componentsmentioning

confidence: 99%

“…Its parameters are listed in Table 3 (see the "all" model). Even if the value of the scale length is larger than the range over which observational constraints are found, a combined fit to multiple source redshift image systems allows us to determine r sP and its uncertainty (Limousin et al 2008). This is an important step in estimating the concentration (see Sect.…”

Section: Nfw Profilementioning

confidence: 99%

“…The total mass map can be obtained with either parametric models in which the contribution from cluster-sized DM halos can be considered with the main galactic DM halos (Natarajan et al 1998;Limousin et al 2008) or non-parametric analyses, where dark matter meso-structures and galactic contributions are seen as deviations from smooth-averaged profiles (Saha et al 2007). Mass in stars and stellar remnants is estimated from galaxy luminosity assuming suitable stellar mass to light ratios.…”

Section: Introductionmentioning

confidence: 99%

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A multiwavelength strong lensing analysis of baryons and dark matter in the dynamically active cluster AC 114

Sereno

Lubini

Jetzer

2010

A&A

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Context. Strong lensing studies can provide detailed mass maps of the inner regions even in dynamically active galaxy clusters. Aims. We illustrate the important role of a proper modelling of the intracluster medium, i.e., the main baryonic component. We demonstrate that the addition of a new contribution accounting for the gas can increase the statistical significance of the lensing model. Methods. We propose a parametric method for strong lensing analyses that exploits multiwavelength observations. The mass model accounts for cluster-sized dark matter halos, galaxies (whose stellar mass can be obtained from optical analyses), and the intracluster medium. The gas distribution is fitted to lensing data exploiting prior knowledge from X-ray observations. This gives an unbiased insight into each matter component and allows us to study the dynamical status of a cluster. The method was applied to AC 114, an irregular X-ray cluster. Results. We find positive evidence of dynamical activity, the dark matter distribution being shifted and rotated with respect to the gas. On the other hand, the dark matter follows the galaxy density in terms of both shape and orientation, illustrating the collisionless nature of dark matter. The inner region ( < ∼ 250 kpc) is underluminous in optical bands, whereas the gas fraction (∼20 ± 5%) slightly exceeds typical values. Evidence of lensing and X-ray suggests that the cluster develops in the plane of the sky and is not affected by the lensing over-concentration bias. Despite the dynamical activity, the matter distribution seems to agree with predictions of N-body simulations. An universal cusped profile provides a good description of either the overall or the dark matter distribution, whereas theoretical scaling relations seem to be accurately fitted.

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“…First, such events can A&A 519, A90 (2010) be used to investigate the inner regions of the lenses. Thus, they can be used to test the predictions of the cold-dark-matter paradigm on the inner structure of dark matter halos (Meneghetti et al 2001;Mao et al 2004;Sand et al 2004;Meneghetti et al 2007b;Limousin et al 2008). Second, they can be used to recover the mass distribution in the center of the lenses, providing complementary informations to those obtained from weak lensing (Bradač et al 2005;Diego et al 2005;Cacciato et al 2006;Limousin et al 2007;Merten et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Strong lensing in the MARENOSTRUM UNIVERSE

Meneghetti

Fedeli

Pace

et al. 2010

A&A

152

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Context. Strong lensing is one of the most direct probes of mass distribution in the inner regions of galaxy clusters. It can be used to constrain the density profiles and to measure the mass of the lenses. Moreover, the abundance of strong lensing events can be used to constrain structure formation and cosmological parameters through the so-called "arc-statistics" approach. However, several issues related to the use of strong lensing clusters in cosmological applications are still controversial, leading to the suspicion that several biases may affect this very peculiar class of objects. Aims. With this study we aim a better understanding of the properties of galaxy clusters that can potentially act as strong lenses. Methods. We do so by investigating the properties of a large sample of galaxy clusters extracted from the N-body/hydrodynamical simulation MareNostrum Universe. We perform ray-tracing simulations with each of them and identify those objects capable of producing strong lensing effects. We explore the correlation between the cross section for lensing and many properties of clusters, such as mass, three-dimensional and projected shapes, their concentrations, the X-ray luminosity, and the dynamical activity. Results. We quantify the minimal cluster mass required for producing both multiple images and large distortions. While we do not measure a significant excess of triaxiality in strong lensing clusters, we find that the probability of strong alignments between the major axes of the lenses and the line of sight is a growing function of the lensing cross section. In projection, the strong lenses appear rounder within R 200 , but we find that their cores tend to be more elliptical as the lensing cross section increases. As a result of the orientation bias, we also find that the cluster concentrations estimated from the projected density profiles tend to be biased high. The X-ray luminosity of strong lensing clusters tend to be higher than for normal lenses of similar mass and redshift. This is particularly significant for the least massive lenses. Finally, we find that the strongest lenses generally exhibit an excess of kinetic energy within the virial radius, thus indicating that they are more dynamically active than the usual clusters. Conclusions. We conclude that strong lensing clusters are a very peculiar class of objects, affected by many selection biases that need to be properly modeled when using them to study the inner structure of galaxy clusters or to constrain the cosmological parameters.

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Strong lensing in Abell 1703: constraints on the slope of the inner dark matter distribution

Cited by 104 publications

References 67 publications

The strongest gravitational lenses

The strongest gravitational lenses

A multiwavelength strong lensing analysis of baryons and dark matter in the dynamically active cluster AC 114

Strong lensing in the MARENOSTRUM UNIVERSE

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