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Related papers: Self-Calibration for 3-point Intrinsic Alignment A…

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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

The intrinsic alignment (IA) of galaxies is a major astrophysical contaminant to weak gravitational lensing measurements, and the study of its dependence on galaxy properties helps provide meaningful physical priors that aid cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-16 Christos Georgiou , Nora Elisa Chisari , Maciej Bilicki , Francesco La Barbera , Nicola R. Napolitano , Nivya Roy , Crescenzo Tortora

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…

We present a method for removal of the contaminating effects of intrinsic galaxy alignments, in measurements of cosmic shear from multi-colour weak lensing surveys. The method down-weights pairs which are likely to be close in three…

Astrophysics · Physics 2007-05-23 Catherine Heymans , Alan Heavens

We show that the spatial correlation of the intrinsic alignments (IAs) of galaxies, measured in galaxy redshift surveys, offers a precision route to improve the geometrical and dynamical constraints on cosmology. The IA has been treated as…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-25 Atsushi Taruya , Teppei Okumura

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…

Intrinsic alignments (IAs) of galaxies are an important contaminant for cosmic shear studies, but the modelling is complicated by the dependence of the signal on the source galaxy sample. In this paper, we use the halo model formalism to…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-16 Maria Cristina Fortuna , Henk Hoekstra , Benjamin Joachimi , Harry Johnston , Nora Elisa Chisari , Christos Georgiou , Constance Mahony

Intrinsic alignment (IA) modelling and photometric redshift estimation are two of the main sources of systematic uncertainty in weak lensing surveys. We investigate the impact of redshift errors and their interplay with different IA models.…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-26 Silvan Fischbacher , Tomasz Kacprzak , Jonathan Blazek , Alexandre Refregier

In this third paper of a series on radio weak lensing for cosmology with the Square Kilometre Array, we scrutinise synergies between cosmic shear measurements in the radio and optical/near-IR bands for mitigating systematic effects. We…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Stefano Camera , Ian Harrison , Anna Bonaldi , Michael L. Brown

Cosmic shear leads to a correlation of the observed ellipticities of galaxies, an effect which is used to place constraints on cosmological parameters, and to explore the evolution of dark matter and dark energy in the universe. However, a…

Astrophysics · Physics 2009-11-11 Lindsay King

Intrinsic alignments (IA), the coherent alignment of intrinsic galaxy orientations, can be a source of a systematic error of weak lensing surveys. The redshift evolution of IA also contains information about the physics of galaxy formation…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-26 Motonari Tonegawa , Teppei Okumura , Tomonori Totani , Gavin Dalton , Karl Glazebrook , Kiyoto Yabe

We introduce a self-calibration method that can be applied to the intrinsic ellipticity--intrinsic ellipticity (II) and gravitational shear -- intrinsic ellipticity (GI) types of intrinsic alignment of galaxies. The method combines previous…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 Ji Yao , Mustapha Ishak , M. A. Troxel

We report the first evidence for intrinsic alignment (IA) of red galaxies at $z>1$. We measure the gravitational shear-intrinsic ellipticity (GI) cross-correlation function at $z\sim1.3$ using galaxy positions from the FastSound…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-04 Motonari Tonegawa , Teppei Okumura

We present a systematic study of cosmological parameter bias in weak lensing and large-scale structure analyses for upcoming imaging surveys induced by the interplay of intrinsic alignments (IA) and photometric redshift (photo-z) model…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-30 C. Danielle Leonard , Markus Michael Rau , Rachel Mandelbaum

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

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

Cosmic shear is a powerful probe of cosmology, but it is affected by the intrinsic alignment (IA) of galaxy shapes with the large-scale structure. Upcoming surveys like Euclid and Vera C. Rubin Observatory's Legacy Survey of Space and Time…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Laila Linke , Susan Pyne , Benjamin Joachimi , Christos Georgiou , Kai Hoffmann , Rachel Mandelbaum , Sukhdeep Singh

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

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

Intrinsic alignments of galaxies can mimic to an extent the effects of shear caused by weak gravitational lensing. Previous studies have shown that for shallow surveys with median redshifts z_m = 0.1, the intrinsic alignment dominates the…

Astrophysics · Physics 2009-11-07 Catherine Heymans , Alan Heavens