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The distortion of distant galaxy images by large-scale structure

Blandford, R. D. and Saust, A. B. and Brainerd, T. G. and Villumsen, J. V. (1991) The distortion of distant galaxy images by large-scale structure. Monthly Notices of the Royal Astronomical Society, 251 (4). pp. 600-627. ISSN 0035-8711. doi:10.1093/mnras/251.4.600.

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Inhomogeneity in the distribution of mass in the universe on scales ≲ 100 Mpc can generate a coherent shear distortion or polarization of the images of background galaxies. This distortion may be measurable over patches of the sky up to a few square degrees in size. If this distortion is measured, or conversely, if its magnitude is limited, it should help us understand the degree to which luminosity traces the underlying mass over cosmological scales. A prescription is given for quantifying the galaxy distortion and a propagation equation for its evolution in an inhomogeneous universe is derived. The creation of shear by inhomogeneity is illustrated using model kinematic universes comprising random distributions of point masses, spheres and circular discs designed to simulate the superclusters, voids and ‘walls’ reported in galaxy velocity surveys. Using these simulations, we estimate that an rms induced ellipticity of |p|_(rms) ˜ 0.2Ω_(LSS) (where Ω_(LSS) is the fraction of the mass of the universe clustered on the large scale) will be produced. The angular correlation length is ˜ 1.6°. In an alternative prescription, the universe is modelled using a power spectrum of density fluctuations and the mean correlation function is computed both analytically and numerically. In these simulations we find that |p|_(rms) ˜0.02 for biased cold dark matter models of an Einslein–De Sitter universe, and the effective correlation length is θ_(1/2) ˜ 0.5^ΰ. For a hot dark matter dominated universe the correlation length is θ_(1/2) ˜ 0.7^ΰ. The faint, blue galaxies discovered by Tyson and collaborators have a surface density of ˜ 3 × 10^5 deg^(−2) and should provide an ideal set of sources for measuring this effect.

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Blandford, R. D.0000-0002-1854-5506
Additional Information:© 1991 Royal Astronomical Society. Provided by the NASA Astrophysics Data System. Accepted 1991 April 12. Received 1991 April 8; in original form 1991 January 25. This research was supported by the National Science Foundation under grants AST 86-15325, AST 89-15326 (RDB) and AST 89-21001 (NV), the Carlsberg Foundation and the Danish Research Academy (ABS). Parts of the calculations were performed at the Ohio Supercomputer Center. We thank S. Cranmer and R. Emmering for assistance with the graphics. We are indebted to B. Fort and T. Tyson for advice and encouragement and the referee S. White for helpful suggestions which led to an improvement in the manuscript.
Funding AgencyGrant Number
NSFAST 86-15325
NSFAST 89-15326
NSFAST 89-21001
Carlsberg FoundationUNSPECIFIED
Danish Research AcademyUNSPECIFIED
Issue or Number:4
Record Number:CaltechAUTHORS:20190521-165452787
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Official Citation:R. D. Blandford, A. B. Saust, T. G. Brainerd, J. V. Villumsen, The distortion of distant galaxy images by large-scale structure, Monthly Notices of the Royal Astronomical Society, Volume 251, Issue 4, 15 August 1991, Pages 600–627,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95659
Deposited By: George Porter
Deposited On:23 May 2019 14:39
Last Modified:16 Nov 2021 17:14

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