Image Analysis for Cosmology: Shape Measurement Challenge Review &amp; Results from the Mapping Dark Matter Challenge

Kitching, Thomas D.; Rhodes, Jason; Heymans, Catherine; Massey, Richard; Liu, Q.; Cobzarenco, M.; Cragin, B. L.; Hassaïne, Abdelâali; Kirkby, D.; Lok, E. Jin; Margala, Daniel; Moser, Jürgen; O'Leary, Marion T.; Pires, Ana M.; Yurgenson, Sergey

doi:10.48550/arxiv.1204.4096

Cited by 4 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Public challenges like the GRavitational lEnsing Accuracy Testing (GREAT) projects have been launched to reach out to a larger community, in particular computer science, to invite more ideas to tackle the problem of galaxy shape measurement. This contains GREAT08 (Bridle et al 2009(Bridle et al , 2010, GREAT10 (Kitching et al 2011a(Kitching et al , 2012a(Kitching et al , 2013, and GREAT3 (Mandelbaum et al 2014), as well as two 'Kaggle' crowdsourcing challenges (Kitching et al 2012b, Harvey et al 2014.…”

Section: Image Simulationsmentioning

confidence: 99%

Cosmology with cosmic shear observations: a review

2015

View full text Add to dashboard Cite

Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are coherently deformed by the tidal field of matter inhomogeneities along the line of sight. By measuring galaxy shape correlations, we can study the properties and evolution of structure on large scales as well as the geometry of the Universe. Thus, cosmic shear has become a powerful probe into the nature of dark matter and the origin of the current accelerated expansion of the Universe. Over the last years, cosmic shear has evolved into a reliable and robust cosmological probe, providing measurements of the expansion history of the Universe and the growth of its structure. We review here the principles of weak gravitational lensing and show how cosmic shear is interpreted in a cosmological context. Then we give an overview of weak-lensing measurements, and present the main observational cosmic-shear results since it was discovered 15 years ago, as well as the implications for cosmology. We then conclude with an outlook on the various future surveys and missions, for which cosmic shear is one of the main science drivers, and discuss promising new weak cosmological lensing techniques for future observations.

show abstract

Section: Image Simulationsmentioning

confidence: 99%

Cosmology with cosmic shear observations: a review

2015

View full text Add to dashboard Cite

show abstract

“…At each point of the lens field, an average is taken over a number of nearby sources to smooth out the intrinsic ellipticity of the galaxies from that caused by the lens (see e.g. [69,71,72]). Observationally, the field is directly related to the reduced shear, g, (see e.g.…”

Section: A Cluster Lensing Basicsmentioning

confidence: 99%

Galaxy cluster lensing masses in modified lensing potentials

Jennings

Merten

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

show abstract

“…The reduction of shear and photometric redshift systematics is the thrust of ongoing investigations. Shear estimation methods are being tested and improved upon via extensive simulation tests [66,67,68,69], and the possibility of self-calibrating systematics from joint shear and magnification analyses of the weak lensing signal has been noted [70,71,72,73]. In addition, the use of spectroscopic sources for weak lensing mass calibration [74] entirely bypasses both sources of systematic errors.…”

Section: Systematics: Current Limitations and Future Prospectsmentioning

confidence: 99%

Growth of cosmic structure: Probing dark energy beyond expansion

Huterer

Kirkby

Bean

et al. 2015

Astroparticle Physics

142

107

View full text Add to dashboard Cite

The quantity and quality of cosmic structure observations have greatly accelerated in recent years, and further leaps forward will be facilitated by imminent projects. These will enable us to map the evolution of dark and baryonic matter density fluctuations over cosmic history. The way that these fluctuations vary over space and time is sensitive to several pieces of fundamental physics: the primordial perturbations generated by GUT-scale physics; neutrino masses and interactions; the nature of dark matter and dark energy. We focus on the last of these here: the ways that combining probes of growth with those of the cosmic expansion such as distance-redshift relations will pin down the mechanism driving the acceleration of the Universe.One way to explain the acceleration of the Universe is invoke dark energy parameterized by an equation of state w. Distance measurements provide one set of constraints on w, but dark energy also affects how rapidly structure grows; the greater the acceleration, the more suppressed the growth of structure. Upcoming surveys are therefore designed to probe w with direct observations of the distance scale and the growth of structure, each complementing the other on systematic errors and constraints on dark energy. A consistent set of results will greatly increase the reliability of the final answer.Another possibility is that there is no dark energy, but that General Relativity does not describe the laws of physics accurately on large scales. While the properties of gravity have been measured with exquisite precision at stellar system scales and densities, within our solar system and by binary pulsar systems, its properties in different environments are poorly constrained. To fully understand if General Relativity is the complete theory of gravity we must test gravity across a spectrum of scales and densities. Rapid developments in gravitational wave astronomy and numerical relativity are directed at testing gravity in the high curvature, high density regime. Cosmological evolution provides a polar opposite test bed, probing how gravity behaves in the lowest curvature, low density environments.There are a number of different implementations of astrophysically relevant modifications of gravity. Generically, the models are able to reproduce the distance measurements but at the cost of altering the growth of structure. In particular, as detailed below, the Poisson equation relating over-densities to gravitational potentials is altered, and the potential that determines the geodesics of relativistic particles (such as photons) arXiv:1309.5385v2 [astro-ph.CO]

show abstract

Image Analysis for Cosmology: Shape Measurement Challenge Review & Results from the Mapping Dark Matter Challenge

Cited by 4 publications

References 19 publications

Cosmology with cosmic shear observations: a review

Cosmology with cosmic shear observations: a review

Galaxy cluster lensing masses in modified lensing potentials

Growth of cosmic structure: Probing dark energy beyond expansion

Contact Info

Product

Resources

About