The Intrinsic Alignment of Galaxies and its Impact on Weak Gravitational Lensing in an Era of Precision Cosmology

By M. Troxel, M. Ishak. 2014

253 citations recorded by the source corpus.

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 of galaxies, e.g., cosmic shear that measures the minute distortions of background galaxy images by intervening cosmic structure. Weak lensing and cosmic shear promise to be a powerful probe of astrophysics and cosmology, constraining models of dark energy, measuring the evolution of structure in the universe, and testing theories of gravity on cosmic scales. However, the intrinsic alignment of galaxies -- their shape and orientation before being lensed -- may pose a great challenge to the use of weak gravitational lensing as an accurate cosmological probe, and has been identified as one of the primary physical systematic biases in cosmic shear studies. Correlations between this intrinsic alignment and the lensing signal can persist even for large physical separations, and isolating the effect of intrinsic alignment from weak lensing is not trivial. A great deal of work in the last two decades has been devoted to understanding and characterizing this intrinsic alignment, which is also a direct and complementary probe of structure formation and evolution in its own right. In this review, we report in a systematic way the state of our understanding of the intrinsic alignment of galaxies, with a particular emphasis on its large-scale impact on weak lensing measurements and methods for its isolation or mitigation. (Abridged)

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9dd28da49771d2c5a3a6a608b68b6bb70d2bcf89

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Citations in the corpus

CFHTLenS revisited: assessing concordance with Planck including astrophysical systematics (2016, background): “…2010; Bonnett et al. 2016) and intrinsic alignments (IA) of galaxies (e.g. Hirata & Seljak 2004; Bridle & King 2007; Joachimi et al. 2011, 2015; Troxel & Ishak 2015), along with additive and multiplicative corrections to the lensing observables, for instance due to point spread function…”
Practical Weak-lensing Shear Measurement with Metacalibration (2017, background): “Remarks on Intrinsic Alignments In the above we assumed that P (eα, eβ) is separable at zero shear, but this assumption breaks down for physically associated galaxies (e.g. Hirata et al. 2007), an affect known as “intrinsic alignments” (IA; for a recent review, see Troxel & Ishak 2015).”
KiDS-450: cosmological parameter constraints from tomographic weak gravitational lensing (2016, background): “…from residual systematics in the shear measurement method, intrinsic ellipticity selection biases from the object detection stage or the photometric redshift selection, or from the intrinsic alignment of nearby galaxies (see e.g. Troxel & Ishak 2015; Joachimi et al. 2015, and references therein).”
Gravitational lensing analysis of the Kilo-Degree Survey (2015, unknown): “These could arise from residual systematics in the shape measurement method or from the intrinsic alignment of nearby galaxies (see Troxel & Ishak 2015, and references therein).”
The first-year shear catalog of the Subaru Hyper Suprime-Cam Subaru Strategic Program Survey (2017, background): “…for the ensemble of galaxies, avoiding certain systematic errors in the process. alignments of galaxy shapes (Joachimi et al. 2015; Kiessling et al. 2015; Kirk et al. 2015; Troxel & Ishak 2015) and the impact of baryonic effects on the matter power spectrum (Zentner et al. 2013; Mead et al. 2015).”
Core Cosmology Library: Precision Cosmological Predictions for LSST (2018, background): “…lensing, for example, phenomena that can lead to biases include the impact of baryons on the distribution of matter and the intrinsic alignments of galaxies (e.g. van Daalen et al. 2011; Semboloni et al. 2011; Troxel & Ishak 2015; Krause et al. 2016; Blazek et al. 2017; Chisari et al. 2018).”
Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data (2019, background): “4.2 Intrinsic alignment model The so-called intrinsic alignment (IA) of galaxy shapes is another major astrophysical systematic in the measurement of the cosmic shear TPCFs (see Kirk et al. 2015; Troxel & Ishak 2015, for recent reviews).”