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Title:

The non-Gaussian tail of cosmic-shear statistics

Description:

Due to gravitational instability, an initially Gaussian density field develops non-Gaussian features as the Universe evolves. The most prominent non-Gaussian features are massive haloes, visible as clusters of galaxies. The distortion of high-redshift galaxy images due to the tidal gravitational field of the large-scale matter distribution, call...

Due to gravitational instability, an initially Gaussian density field develops non-Gaussian features as the Universe evolves. The most prominent non-Gaussian features are massive haloes, visible as clusters of galaxies. The distortion of high-redshift galaxy images due to the tidal gravitational field of the large-scale matter distribution, called cosmic shear, can be used to investigate the statistical properties of the LSS. In particular, non-Gaussian properties of the LSS will lead to a non-Gaussian distribution of cosmic-shear statistics. The aperture mass (Map) statistics, recently introduced as a measure for cosmic shear, is particularly well suited for measuring these non-Gaussian properties. In this paper we calculate the highly non-Gaussian tail of the aperture mass probability distribution, assuming Press-Schechter theory for the halo abundance and the ‘universal ’ density profile of haloes as obtained from numerical simulations. We find that for values of Map much larger than its dispersion, this probability distribution is closely approximated by an exponential, rather than a Gaussian. We determine the amplitude and shape of this exponential for various cosmological models and aperture sizes, and show that wide-field imaging surveys can be used to distinguish between some of the currently most popular cosmogonies. Our study here is complementary to earlier cosmic-shear investigations which focussed more on two-point statistical properties. Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-01-04

Source:

http://arxiv.org/pdf/astro-ph/9904192v1.pdf

http://arxiv.org/pdf/astro-ph/9904192v1.pdf Minimize

Document Type:

text

Language:

en

DDC:

519 Probabilities & applied mathematics *(computed)*

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Metadata may be used without restrictions as long as the oai identifier remains attached to it.

Metadata may be used without restrictions as long as the oai identifier remains attached to it. Minimize

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Title:

Statistics of dark matter haloes expected from weak lensing surveys

Description:

As first discussed by Webster (1985), the tidal gravitational field of clusters of galaxies distorts the images of background galaxies in a characteristic way. After the first extreme

As first discussed by Webster (1985), the tidal gravitational field of clusters of galaxies distorts the images of background galaxies in a characteristic way. After the first extreme Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-01-05

Source:

http://arxiv.org/pdf/astro-ph/9806071v1.pdf

http://arxiv.org/pdf/astro-ph/9806071v1.pdf Minimize

Document Type:

text

Language:

en

Subjects:

Accepted. Received ; in original form

Accepted. Received ; in original form Minimize

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Metadata may be used without restrictions as long as the oai identifier remains attached to it.

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Title:

Statistics of Dark Matter Haloes Expected From Weak Lensing Surveys

Description:

The distortion of the images of faint high-redshift galaxies can be used to probe the intervening mass distribution. This weak gravitational lensing effect has been used recently to study the (projected) mass distribution of several clusters at intermediate and high redshifts. In addition, the weak lensing effect can be employed to detect (dark)...

The distortion of the images of faint high-redshift galaxies can be used to probe the intervening mass distribution. This weak gravitational lensing effect has been used recently to study the (projected) mass distribution of several clusters at intermediate and high redshifts. In addition, the weak lensing effect can be employed to detect (dark) matter concentrations in the Universe, based on their mass properties alone. Thus it is feasible to obtain a mass-selected sample of `clusters', and thereby probe the full range of their mass-to-light ratios. We study the expected number density of such haloes which can be detected in ongoing and future deep wide-field imaging surveys, using the number density of haloes as predicted by the Press-Schechter theory, and modeling their mass profile by the `universal' density profile found by Navarro, Frenk & White. We find that in all cosmological models considered, the number density of haloes with a signal-to-noise ratio larger than 5 exceeds 10 . Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2009-04-13

Source:

http://www.mpa-garching.mpg.de/~maria/greenreports/mpa98/MPA1099.ps.gz

http://www.mpa-garching.mpg.de/~maria/greenreports/mpa98/MPA1099.ps.gz Minimize

Document Type:

text

Language:

en

Subjects:

Accepted. Received ; in original form

Accepted. Received ; in original form Minimize

DDC:

520 Astronomy & allied sciences *(computed)*

Rights:

Metadata may be used without restrictions as long as the oai identifier remains attached to it.

Metadata may be used without restrictions as long as the oai identifier remains attached to it. Minimize

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Title:

Cosmic shear and halo abundances: Analytical versus numerical results

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Description:

. The aperture mass has been shown in a series of recent publications to be a useful quantitative tool for weak lensing studies, ranging from cosmic shear to the detection of a mass-selected sample of dark matter haloes. Quantitative analytical predictions for the aperture mass have been based on a number of simplifying assumptions. In this pape...

. The aperture mass has been shown in a series of recent publications to be a useful quantitative tool for weak lensing studies, ranging from cosmic shear to the detection of a mass-selected sample of dark matter haloes. Quantitative analytical predictions for the aperture mass have been based on a number of simplifying assumptions. In this paper, we test the reliability of these assumptions and the quality of the analytic approximations, using ray-tracing simulations through a cosmological density field generated by very large N-body simulations. We find that those analytic predictions which take into account the non-linear evolution of the matter distribution, such as the dispersion of the aperture mass and the halo abundance, are surprisingly accurately reproduced with our numerical results, whereas the predictions for the skewness, based on quasi-linear theory, are rather imprecise. In particular, we verify numerically that the probability distribution of the aperture mass decrease. Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2009-04-13

Source:

http://www.mpa-garching.mpg.de/~maria/greenreports/mpa99/MPA1189.ps.gz

http://www.mpa-garching.mpg.de/~maria/greenreports/mpa99/MPA1189.ps.gz Minimize

Document Type:

text

Language:

en

DDC:

520 Astronomy & allied sciences *(computed)*

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Title:

ASTRONOMY AND ASTROPHYSICS Cosmic shear and halo abundances: analytical versus

Author:

Description:

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are:

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are: Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-01-03

Source:

http://arxiv.org/pdf/astro-ph/9907250v2.pdf

http://arxiv.org/pdf/astro-ph/9907250v2.pdf Minimize

Document Type:

text

Language:

en

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Title:

ASTRONOMY AND ASTROPHYSICS Cosmic shear and halo abundances: Analytical versus

Author:

Description:

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are:

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are: Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-01-03

Source:

http://arxiv.org/pdf/astro-ph/9907250v1.pdf

http://arxiv.org/pdf/astro-ph/9907250v1.pdf Minimize

Document Type:

text

Language:

en

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Title:

A new measure for cosmic shear

Author:

Description:

Cosmic shear, i.e., the distortion of images of high-redshift galaxies through the tidal gravitational field of the large-scale matter distribution in the Universe, offers the opportunity to measure the power spectrum of the cosmic density fluctuations without any reference to the relation of dark matter to luminous tracers. We consider here a n...

Cosmic shear, i.e., the distortion of images of high-redshift galaxies through the tidal gravitational field of the large-scale matter distribution in the Universe, offers the opportunity to measure the power spectrum of the cosmic density fluctuations without any reference to the relation of dark matter to luminous tracers. We consider here a new statistical measure for cosmic shear, the aperture mass Map(θ), which is defined as a spatially filtered projected density field and which can be measured directly from the image distortions of high-redshift galaxies. By selecting an appropriate spatial filter function, the dispersion of the aperture mass is a convolution of the power spectrum of the projected density field with a narrow kernel, so that ⟨Map(θ) ⟩ provides a well localized estimate of the power spectrum at wavenumbers s ∼ 5/θ. We calculate ⟨ M2 ⟩ ap for various cosmological models, using the fully non-linear power spectrum of the cosmic density fluctuations. The non-linear evolution yields a significant increase of ⟨ M2 ⟩ ap Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-01-04

Source:

http://arxiv.org/pdf/astro-ph/9708143v1.pdf

http://arxiv.org/pdf/astro-ph/9708143v1.pdf Minimize

Document Type:

text

Language:

en

DDC:

520 Astronomy & allied sciences *(computed)*

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Title:

Statistics of dark matter haloes expected from weak lensing surveys

Description:

The distortion of the images of faint high-redshift galaxies can be used to probe the intervening mass distribution. This weak gravitational lensing effect has been used recently to study the (projected) mass distribution of several clusters at intermediate and high redshifts. In addition, the weak lensing effect can be employed to detect (dark)...

The distortion of the images of faint high-redshift galaxies can be used to probe the intervening mass distribution. This weak gravitational lensing effect has been used recently to study the (projected) mass distribution of several clusters at intermediate and high redshifts. In addition, the weak lensing effect can be employed to detect (dark) matter concentrations in the Universe, based on their mass properties alone. Thus it is feasible to obtain a mass-selected sample of `clusters', and thereby probe the full range of their mass-to-light ratios. We study the expected number density of such haloes which can be detected in ongoing and future deep wide-field imaging surveys, using the number density of haloes as predicted by the Press-Schechter theory, and modeling their mass profile by the `universal' density profile found by Navarro, Frenk & White. We find that in all cosmological models considered, the number density of haloes with a signal-to-noise ratio larger than 5 exceeds 10 per square degree. With the planned MEGACAM imaging survey of $\sim 25 deg^2$, it will be easily possible to distinguish between the most commonly discussed cosmological parameter sets. ; Comment: 8 pages, 7 figures, submitted to MNRAS Minimize

Year of Publication:

1998-06-04

Document Type:

text

Subjects:

Astrophysics

Astrophysics Minimize

DDC:

520 Astronomy & allied sciences *(computed)*

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Title:

The non-Gaussian tail of cosmic-shear statistics

Description:

Due to gravitational instability, an initially Gaussian density field develops non-Gaussian features as the Universe evolves. The most prominent non-Gaussian features are massive haloes, visible as clusters of galaxies. The distortion of high-redshift galaxy images due to the tidal gravitational field of the large-scale matter distribution, call...

Due to gravitational instability, an initially Gaussian density field develops non-Gaussian features as the Universe evolves. The most prominent non-Gaussian features are massive haloes, visible as clusters of galaxies. The distortion of high-redshift galaxy images due to the tidal gravitational field of the large-scale matter distribution, called cosmic shear, can be used to investigate the statistical properties of the LSS. In particular, non-Gaussian properties of the LSS will lead to a non-Gaussian distribution of cosmic-shear statistics. The aperture mass ($M_{\rm ap}$) statistics, recently introduced as a measure for cosmic shear, is particularly well suited for measuring these non-Gaussian properties. In this paper we calculate the highly non-Gaussian tail of the aperture mass probability distribution, assuming Press-Schechter theory for the halo abundance and the `universal' density profile of haloes as obtained from numerical simulations. We find that for values of $M_{\rm ap}$ much larger than its dispersion, this probability distribution is closely approximated by an exponential, rather than a Gaussian. We determine the amplitude and shape of this exponential for various cosmological models and aperture sizes, and show that wide-field imaging surveys can be used to distinguish between some of the currently most popular cosmogonies. Our study here is complementary to earlier cosmic-shear investigations which focussed more on two-point statistical properties. ; Comment: 9 pages, 5 figures, submitted to MNRAS Minimize

Year of Publication:

1999-04-15

Document Type:

text

Subjects:

Astrophysics

Astrophysics Minimize

DDC:

519 Probabilities & applied mathematics *(computed)*

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Title:

Statistische Untersuchungen zum schwachen kosmologischen Gravitationslinseneffekt

Author:

Publisher:

Ludwig-Maximilians-Universität München

Year of Publication:

2000-02-03

Document Type:

Dissertation ; NonPeerReviewed

Subjects:

Fakultät für Physik

Fakultät für Physik Minimize

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http://edoc.ub.uni-muenchen.de/337/

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