Effects of Weak Gravitational Lensing from Large-Scale Structure on the Determination of [CLC][ITAL]q[/ITAL][TINF]0[/TINF][/CLC]

Wambsganß, J.; Cen, Renyue; Xu, Guoqing; Ostriker, Jeremiah P.

doi:10.1086/310470

Cited by 126 publications

(154 citation statements)

References 39 publications

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“…Our approach also bears some similarity to analyses which start with a model of the matter distribution in the universe-obtained analytically [10,11,12] or from N-body codes [13,14,15,16]-and then project the matter into lens planes lying between the source and observer. Ray shooting methods are used to numerically obtain bending angles of a large sample of photons, from which the amplification and shear distribution of images can then be computed.…”

Section: Our Methodsmentioning

confidence: 99%

New method for determining cumulative gravitational lensing effects in inhomogeneous universes

1998

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We present a new approach to calculating the statistical distributions for magnification, shear, and rotation of images of cosmological sources due to gravitational lensing. In this approach one specifies an underlying Robertson-Walker cosmological model together with relevant information on the clumping of matter on scales much smaller than the Hubble radius. The geodesic deviation equation is then integrated backwards in time until the desired redshift is reached, using a Monte Carlo procedure wherein each photon beam in effect "creates its own universe" as it propagates. The approach is somewhat similar to that used in "Swiss cheese" models, but the "cheese" has been completely eliminated, the matter distribution in the "voids" need not be spherically symmetric, the total mass in each void need equal the corresponding Robertson-Walker mass only on average, and we do not impose an "opaque radius" cutoff. The case where the matter in the universe consists of point masses is studied in detail, and it is shown that the statistical distributions of the lensing images are essentially independent of both the mass spectrum and the clustering properties of the point masses, provided that the clustering is spherical. Detailed results for the distribution of the magnification of images are 1 presented for the point mass case, as well as a number of other matter distributions. We apply our results (i) to argue that the positive correlation recently found between quasar luminosity and the number of absorption line systems is not likely to be due to lensing, and (ii) to determine the amount of "noise" and possible bias produced by lensing in measurements of q 0 using distant supernovae.

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Section: Our Methodsmentioning

confidence: 99%

New method for determining cumulative gravitational lensing effects in inhomogeneous universes

1998

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“…Gravitational lensing does not appear to be a major issue for the redshifts considered so far. The highest redshift supernovae may be affected by lensing individually, but the overall effect should be minimal (Wambsganss et al 1997, Holz & Wald 1998, Amanullah et al 2003, Gunnarsson et al 2006, Jönsson et al 2006. The absorption due to dust in our own Milky Way is also fairly easily corrected.…”

Section: The Expansion History Of the Universementioning

confidence: 98%

Supernovae and cosmology

Leibundgut

2007

Gen Relativ Gravit

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The extreme luminosity and their fairly unique temporal behaviour have made supernovae a superb tool to measure distances in the universe. As complex astrophysical events they provide interesting insights into explosion physics, explosive nucleosynthesis, hydrodynamics of the explosion and radiation transport. They are an end product of stellar evolution and provide clues to the stellar composition. Since they can be observed at large distances they have become critical probes to further explore astrophysical effects, like dust properties in external galaxies and the star formation history of galaxies. Some of the astrophysics interferes with the cosmological applications of supernovae. The local velocity field, distorted by the gravitational attraction of the local large scale structure, and the reddening law appear at the moment the major limitations in the accuracy with which cosmological parameters can be determined. These absorption effects can introduce a secondary bias into the observations of the distant supernovae, which needs to be carefully evaluated. Supernovae have been used for the measurement of the Hubble constant, i.e. the current expansion rate of the universe, and the accelerated cosmic expansion directly inferred from the apparent faintness of the distant supernovae.

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“…The apparent flux from the source is increased by some factor , which is usually $1, and the apparent distance D app thus differs from the true distance D according to D app ¼ D À1=2 . This phenomenon of course occurs for all standard candles, and has long been recognized as an issue for SNe [7][8][9], but its importance relative to intrinsic dispersion is much greater for gravitational waves.…”

Section: Introductionmentioning

confidence: 99%

Reducing the weak lensing noise for the gravitational wave Hubble diagram using the non-Gaussianity of the magnification distribution

2010

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Gravitational wave sources are a promising cosmological standard candle because their intrinsic luminosities are determined by fundamental physics (and are insensitive to dust extinction). They are, however, affected by weak lensing magnification due to the gravitational lensing from structures along the line of sight. This lensing is a source of uncertainty in the distance determination, even in the limit of perfect standard candle measurements. It is commonly believed that the uncertainty in the distance to an ensemble of gravitational wave sources is limited by the standard deviation of the lensing magnification distribution divided by the square root of the number of sources. Here we show that by exploiting the nonGaussian nature of the lensing magnification distribution, we can improve this distance determination, typically by a factor of 2-3; we provide a fitting formula for the effective distance accuracy as a function of redshift for sources where the lensing noise dominates.

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Effects of Weak Gravitational Lensing from Large-Scale Structure on the Determination of [CLC][ITAL]q[/ITAL][TINF]0[/TINF][/CLC]

Cited by 126 publications

References 39 publications

New method for determining cumulative gravitational lensing effects in inhomogeneous universes

New method for determining cumulative gravitational lensing effects in inhomogeneous universes

Supernovae and cosmology

Reducing the weak lensing noise for the gravitational wave Hubble diagram using the non-Gaussianity of the magnification distribution

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