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Related papers: Intrinsic Shear and Galaxy Alignments: A Quantitat…

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Galaxy intrinsic alignments (IA) are a critical uncertainty for current and future weak lensing measurements. We describe a perturbative expansion of IA, analogous to the treatment of galaxy biasing. From an astrophysical perspective, this…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-13 Jonathan Blazek , Niall MacCrann , M. A. Troxel , Xiao Fang

Intrinsic alignments (IA) of galaxies is one of the key secondary signals to cosmic shear measurements, and must be modeled to interpret weak lensing data and infer the correct cosmology. There are large uncertainties in the physical…

The intrinsic alignments (IA) of galaxies, regarded as a contaminant in weak lensing analyses, represents the correlation of galaxy shapes due to gravitational tidal interactions and galaxy formation processes. As such, understanding IA is…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-23 Sneh Pandya , Yuanyuan Yang , Nicholas Van Alfen , Jonathan Blazek , Robin Walters

Coherent alignments of galaxy shapes, often called "intrinsic alignments" (IA), are the most significant source of astrophysical uncertainty in weak lensing measurements. We develop the tidal alignment model of IA and demonstrate its…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-19 Jonathan Blazek , Uroš Seljak , Rachel Mandelbaum

Accurate measurements of the cosmic shear signal require a separation of the true weak gravitational lensing signal from intrinsic shape correlations of galaxies. These `intrinsic alignments' of galaxies originate from galaxy formation…

Astrophysics of Galaxies · Physics 2020-10-19 Jolanta Zjupa , Björn Malte Schäfer , Oliver Hahn

We present a new method for measuring the scale dependence of the intrinsic alignment (IA) contamination to the galaxy-galaxy lensing signal, which takes advantage of multiple shear estimation methods applied to the same source galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-01 C. Danielle Leonard , Rachel Mandelbaum

We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing,…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-19 Jonathan Blazek , Zvonimir Vlah , Uroš Seljak

The galaxy intrinsic alignment (IA) is a dominant source of systematics in weak lensing (WL) studies. In this paper, by employing large simulations with semi-analytical galaxy formation, we investigate the IA effects on WL peak statistics.…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Tianyu Zhang , Xiangkun Liu , Chengliang Wei , Guoliang Li , Yu Luo , Xi Kang , Zuhui Fan

Weak gravitational lensing (WL) peak statistics capture cosmic non-linear structures and can provide additional cosmological information complementary to cosmic shear two-point correlation analyses. They have been applied to different WL…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Tianyu Zhang , Xiangkun Liu , Ziwei Li , Chengliang Wei , Guoliang Li , Yu Luo , Xi Kang , Zuhui Fan

Developing analysis pipelines based on statistics beyond two-point functions is critical for extracting a maximal amount of cosmological information from current and upcoming weak lensing surveys. In this paper, we study the impact of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-12 Joachim Harnois-Déraps , Nicolas Martinet , Robert Reischke

The intrinsic alignment (IA) of galaxies is potentially a major limitation in deriving cosmological constraints from weak lensing surveys. In order to investigate this effect we assign intrinsic shapes and orientations to galaxies in the…

Cosmic shear surveys have great promise as tools for precision cosmology, but can be subject to systematic errors including intrinsic ellipticity correlations of the source galaxies. The intrinsic alignments are believed to be small for…

Astrophysics · Physics 2010-10-28 Christopher M. Hirata , Uros Seljak

Weak gravitational lensing is one of the most promising cosmological probes to constrain dark matter, dark energy, and the nature of gravity at cosmic scales. Intrinsic alignments (IAs) of galaxies have been recognized as one of the most…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-25 Eske M. Pedersen , Ji Yao , Mustapha Ishak , Pengjie Zhang

We study intrinsic alignments (IA) of galaxy image shapes within the Illustris cosmic structure formation simulations. We investigate how IA correlations depend on observable galaxy properties such as stellar mass, apparent magnitude,…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 Stefan Hilbert , Dandan Xu , Peter Schneider , Volker Springel , Mark Vogelsberger , Lars Hernquist

Galaxy shapes are not randomly oriented, rather they are statistically aligned in a way that can depend on formation environment, history and galaxy type. Studying the alignment of galaxies can therefore deliver important information about…

Galaxy intrinsic alignment can be a severe source of error in weak-lensing studies. The problem has been widely studied by numerical simulations and with heuristic models, but without a clear theoretical justification of its origin and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-11 Giovanni Camelio , Marco Lombardi

The wealth of incoming and future cosmological observations will allow us to map out the structure and evolution of the observable universe to an unprecedented level of precision. Among these observations is the weak gravitational lensing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 M. A. Troxel , Mustapha Ishak

Without mitigation, the intrinsic alignment (IA) of galaxies poses a significant threat to achieving unbiased cosmological parameter constraints from precision weak lensing surveys. Here, we apply for the first time to data a method to…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-24 Charlie MacMahon-Gellér , C. Danielle Leonard

Cosmological weak lensing gives rise to correlations in the ellipticities of faint galaxies. This cosmic shear signal depends upon the matter power spectrum, thus providing a means to constrain cosmological parameters. It has recently been…

Astrophysics · Physics 2009-11-07 Lindsay King , Peter Schneider

In this paper we show how intrinsic alignments can be incorporated consistently in the formalism of 3d weak lensing. We use two different descriptions of the intrinsic galaxy ellipticities, the so-called linear and quadratic model,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Philipp M. Merkel , Bjoern Malte Schaefer
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