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Related papers: On distance and velocity estimation in cosmology

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We only see a small fraction of the matter in the universe, but the rest gives itself away by the impact of its gravity. Peculiar velocities have the potential to be a powerful tool to trace this matter however previous peculiar velocity…

Astrophysics · Physics 2007-08-23 Karen L. Masters

We have measured maximum rotation velocities (Vrot) for a sample of 111 emission-line galaxies with 0.1 < z < 1, observed in the fields of 6 clusters. From these data we construct 'matched' samples of 58 field and 22 cluster galaxies,…

Astrophysics · Physics 2009-11-10 S. P. Bamford , B. Milvang-Jensen , A. Aragon-Salamanca , L. Simard

High-resolution, low-noise observations of the cosmic microwave background (CMB) planned for the near-future will enable new cosmological probes based on re-scattered CMB photons -- the secondary CMB. At the same time, enormous galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-16 Dagoberto Contreras , Matthew C. Johnson , James B. Mertens

We investigate the observational consequences of scalar instabilities in bimetric theory, under the assumption that the Vainshtein mechanism restores general relativity within a certain distance from gravitational sources. We argue that…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 Edvard Mortsell , Jonas Enander

We present a quadratic estimator that detects and reconstructs spatially-varying multiplicative ($m-$) bias in weak lensing shear measurements, by exploiting the $EB$ mode coupling that it generates. The method combines $E$ and $B$ modes…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-08 Konstantinos Tanidis , David Alonso , Lance Miller , Joachim Harnois-Déraps

We examine the V_{CMB} velocities and Tully-Fisher distances of 83 ScI galaxies and find that their velocities contain the same discrete velocity components identified previously by Tifft. After removing the discrete velocity components,…

Astrophysics · Physics 2007-05-23 M. B. Bell , S. P. Comeau , D. G. Russell

Many standard optimization methods for segmentation and reconstruction compute ML model estimates for appearance or geometry of segments, e.g. Zhu-Yuille 1996, Torr 1998, Chan-Vese 2001, GrabCut 2004, Delong et al. 2012. We observe that the…

Computer Vision and Pattern Recognition · Computer Science 2015-05-04 Yuri Boykov , Hossam Isack , Carl Olsson , Ismail Ben Ayed

The interpretation of cosmological observations relies on a notion of an average Universe, which is usually considered as the homogeneous and isotropic Friedmann-Lema\^itre-Robertson-Walker (FLRW) model. However, inhomogeneities may…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-24 Michel-Andrès Breton , Pierre Fleury

Atmospheric motion vectors (AMVs) extracted from satellite imagery are the only wind observations with good global coverage. They are important features for feeding numerical weather prediction (NWP) models. Several Bayesian models have…

Methodology · Statistics 2023-10-26 Patrick Héas , Frédéric Cérou , Mathias Rousset

We present a method that accurately propagates residual uncertainties in photometric redshift distributions into the cosmological inference from weak lensing measurements. The redshift distributions of tomographic redshift bins are…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-23 B. Stölzner , B. Joachimi , A. Korn , H. Hildebrandt , A. H. Wright

Gromov--Wasserstein (GW) distances compare graphs, shapes, and point clouds through internal distances, without requiring a common coordinate system. This invariance is powerful, but discrete GW is a nonconvex quadratic optimal transport…

Machine Learning · Computer Science 2026-05-15 Ao Xu , Tieru Wu

The accurate reconstruction of Cosmic Microwave Background (CMB) maps and the measurement of its power spectrum are crucial for studying the early universe. In this paper, we implement a convolutional neural network to apply the Wiener…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-07 Belén Costanza , Claudia G. Scóccola , Matías Zaldarriaga

One goal of CMB data analysis is to combine data at different frequencies, angular resolutions, and noise levels in order to best extract the component with a Plankian spectral behaviour. A multi-frequency Wiener filtering method has been…

Astrophysics · Physics 2007-05-23 F. R. Bouchet , S. Prunet , S. K. Sethi

The Teerikorpi incompleteness bias in the distance modulus of a galaxy cluster that is determined from incomplete data using the Tully-Fisher (TF) method is discussed differently than has been done in earlier papers of this series. A toy…

Astrophysics · Physics 2007-12-14 Allan Sandage

Massive spectroscopic surveys will measure the redshift space distortion (RSD) induced by galaxy peculiar velocity to unprecedented accuracy. We develop a new method to improve the RSD modeling and to carry out robust reconstruction of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-29 Pengjie Zhang , Jun Pan , Yi Zheng

Full sky surveys of peculiar velocity are arguably the best way to map the large scale structure out to distances of a few times 100 Mpc/h. Using the largest and most accurate ever catalog of galaxy peculiar velocities "Cosmicflows-2", the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Yehuda Hoffman , Helene M. Courtois , R. Brent Tully

We present a scheme based on artificial neural networks (ANN) to estimate the line-of-sight velocities of individual galaxies from an observed redshift-space galaxy distribution. We find an estimate of the peculiar velocity at a galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Hongxiang Chen , Jie Wang , Tianxiang Mao , Juntao Ma , Yuxi Meng , Baojiu Li , Yan-Chuan Cai , Mark Neyrinck , Bridget Falck , Alexander S. Szalay

We introduce a novel, geometry-aware distance metric for the family of von Mises-Fisher (vMF) distributions, which are fundamental models for directional data on the unit hypersphere. Although the vMF distribution is widely employed in a…

Machine Learning · Statistics 2025-04-22 Kisung You , Dennis Shung , Mauro Giuffrè

Measuring distances of cosmological sources such as galaxies, stars and quasars plays an increasingly critical role in modern cosmology. Obtaining the optical spectrum and consequently calculating the redshift as a distance indicator could…

Astrophysics of Galaxies · Physics 2022-01-13 Aidin Momtaz , Mohammad Hossein Salimi , Soroush Shakeri

We present a new method for recovering the underlying velocity field from an observed distribution of galaxies in redshift space. The method is based on a kinematic Zel'dovich relation between the velocity and density fields in redshift…

Astrophysics · Physics 2009-10-22 Adi Nusser , Marc Davis
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