Flux Ratios as a Probe of Dark Substructures in Quadruple-Image Gravitational Lenses

Metcalf, R. Benton; Zhao, Hongsheng

doi:10.1086/339798

Cited by 188 publications

(215 citation statements)

References 19 publications

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“…Small deviations from our assumed m p 500 power spectrum from slight red tilts ( ) or massive neun ∼ 0.9 s trinos ( eV) appear insufficient to change our conclum Շ 1 n sions. Observations of strong gravitational lenses appear to indicate that there is significant small-scale power (Dalal & Kochanek 2002;Metcalf & Madau 2001;Chiba 2002;Metcalf & Zhao 2002), consistent with the values assumed here. Future wide-field surveys like the Large-Aperture Synoptic Survey Telescope 3 or the Supernova/Acceleration Probe 4 will directly measure the convergence angular power on some of the relevant scales, so it will be possible to check whether the assumptions made here are valid.…”

Section: Discussionsupporting

confidence: 87%

Corrective Lenses for High-Redshift Supernovae

Dalal

Holz

Chen

et al. 2003

The Astrophysical Journal

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Weak lensing of high-redshift Type Ia supernovae induces an external dispersion in their observed standard candle brightnesses, comparable in magnitude to the intrinsic dispersion for redshifts . The same matter z 1 1 fluctuations responsible for the magnification of distant supernovae also generate shear in the images of background galaxies. We investigate the possibility of using lensing shear maps constructed from galaxies surrounding the supernovae as a means of correcting the lensing-induced magnification dispersion. We find that a considerable fraction of the lensing dispersion derives from subarcminute scales, which are not probed by shear maps smoothed on arcminute scales. We thus find that weak-lensing shear maps will be of only limited value in reducing the weak-lensing magnification fluctuations of supernovae.

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Section: Discussionsupporting

confidence: 87%

Corrective Lenses for High-Redshift Supernovae

Dalal

Holz

Chen

et al. 2003

The Astrophysical Journal

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“…Various authors tried to compare the amount of Dark Matter Halo substructures predicted by ΛCDM hydrodynamical simulations to the amount of substructures necessary in lensing models to reproduce observed flux ratios (e.g. Metcalf & Madau 2001;Chiba 2002;Dalal & Kochanek 2002;Metcalf & Zhao 2002;Mao et al 2004;Bradač et al 2002Bradač et al , 2004Kochanek & Dalal 2004;Metcalf 2005a). However, it is still unclear whether the amount of substructures necessary in lensing models agrees or not with the hydrodynamical simulation predictions (see e.g.…”

Section: Anomalous Flux Ratiosmentioning

confidence: 99%

Multi-wavelength study of the gravitational lens system RXS J113155.4-123155

Sluse

Claeskens²,

Altiéri

et al. 2006

A&A

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Aims. RXS J113155.4-123155 (z = 0.66) is a quadruply imaged lensed quasar with a resolved Einstein Ring. The goal of this paper is to provide a full characterization of this system, and more particularly accurate astrometry and photometry. These observational constraints constitute a mandatory ingredient for the precise determination of the lens mass profile, the derivation of the Hubble constant H 0 from time delay measurements and investigations on the presence of massive substructures in the lensing galaxy. Methods. Visible and near-infrared imaging observations of RXS J113155.4-123155 were carried out at various epochs using several ground based telescopes and the HST. The frames have been deconvolved using the MCS algorithm. A Singular Isothermal Ellipsoid (SIE) + external shear has been used to model the lensing galaxy potential. Results. MCS deconvolution enables us to separate the flux of the QSO (point-like images) from that of its host galaxy and to accurately track the flux variations of the point-like images in various filters. The deconvolved frames unveil several multiply imaged structures in the Einstein ring and an unidentified object in the vicinity of the lensing galaxy. We discuss the lightcurves and the chromatic flux ratio variations and deduce that both intrinsic variability and microlensing took place during a span longer than one year. We demonstrate that microlensing may easily account for the so called anomalous flux ratios presented in the discovery paper. However, the observed flux ratios are still poorly reproduced when modeling the lens potential with a SIE+shear. We argue that this disagreement can hardly be explained by milli-lensing caused by substructures in the lensing galaxy. A solution proposed in Paper II consists in a more complex lens model including an octupole term to the lens gravitational potential.

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“…Later Mao & Schneider (1998) noted that mass substructure (on much smaller mass and length scales than in the case of clusters) readily explains the observed magnification ratios in a galaxy lens, and more recently, this topic has attracted more attention. There is general agreement that substructure and microlensing are both present and both contribute to anomalous flux ratios in galaxy lenses, but there is considerable debate as to whether the expected cold dark matter substructure can account for the observations (Dalal & Kochanek 2002;Metcalf & Zhao 2002;Evans & Witt 2003;Bradač et al 2004;Amara et al 2006;Macciò & Miranda 2006). Such comparison of observed and model-predicted flux ratios is entirely statistical; it does not attempt to map particular substructures, as the mass of individual clumps is rather small, in the range 10 4 Y10 7 M .…”

Section: Introductionmentioning

confidence: 99%

Meso‐Structure in Three Strong‐lensing Systems

Saha

Williams

Ferreras

2007

ApJ

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We map substructure in three strong-lensing systems having particularly good image data: the galaxy lens MG J0414+053 and the clusters SDSS J1004+411 and ACO 1689. Our method is to first reconstruct the lens as a pixelated mass map and then subtract off the symmetric part (in the galaxy case) or a projected Navarro-Frenk-White profile (for the cluster lenses). In all three systems we find extended irregular structures, or meso-structures, having of order 10% of the total mass. In J0414+053, the meso-structure suggests a tidal tail connecting the main lens with a nearby galaxy; however, this interpretation is tentative. In the clusters, the identification of meso-structure is more secure, especially in ACO 1689, where two independent sets of lensed images imply very similar meso-structure. In all three cases, the meso-structures are correlated with galaxies but much more extended and massive than the stellar components of single galaxies. Such extended structures cannot plausibly persist in such high-density regions without being mixed; the crossing times are too short. The meso-structures therefore appear to be merging or otherwise dynamically evolving systems.

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Flux Ratios as a Probe of Dark Substructures in Quadruple-Image Gravitational Lenses

Cited by 188 publications

References 19 publications

Corrective Lenses for High-Redshift Supernovae

Corrective Lenses for High-Redshift Supernovae

Multi-wavelength study of the gravitational lens system RXS J113155.4-123155

Meso‐Structure in Three Strong‐lensing Systems

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