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Related papers: On methods of estimating cosmological bulk flows

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An increasing number of surveys has been reporting large-scale peculiar motions with sizes and speeds in excess of those allowed by the concordance cosmological model. These are the so called bulk flows, the presence of which has come to be…

General Relativity and Quantum Cosmology · Physics 2026-05-29 Erick Pastén , Christos Tsagas

In this review we present a comprehensive discussion of peculiar velocity field measured recently on very large scales with a novel method using X-ray galaxy clusters as tracers. The measurement is based on the kinematic component of the…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-06 A. Kashlinsky , F. Atrio-Barandela , H. Ebeling

A valuable amount of information is available in peculiar velocities of galaxies. Peculiar velocity surveys have recently allowed the discovery of potential problems with LCDM. Nonetheless, their direct observation through distance…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 G. Lavaux

Kalman-type filtering techniques including cubature Kalman filter (CKF) does not work well in non-Gaussian environments, especially in the presence of outliers. To solve this problem, Huber's M-estimation based robust CKF (RCKF) is proposed…

Systems and Control · Computer Science 2020-03-06 Yang Li , Jing Li , Junjian Qi , Liang Chen

Models optimized for accuracy on single images are often prohibitively slow to run on each frame in a video. Recent work exploits the use of optical flow to warp image features forward from select keyframes, as a means to conserve…

Computer Vision and Pattern Recognition · Computer Science 2018-10-10 Samvit Jain , Joseph E. Gonzalez

Methods based on Deep Learning have recently been applied on astrophysical parameter recovery thanks to their ability to capture information from complex data. One of these methods is the approximate Bayesian Neural Networks (BNNs) which…

Instrumentation and Methods for Astrophysics · Physics 2023-06-21 Héctor J. Hortúa , Luz Ángela García , Leonardo Castañeda C

We consider the estimation of carbon dioxide flux at the ocean-atmosphere interface, given weighted averages of the mixing ratio in a vertical atmospheric column. In particular we examine the dependence of the posterior covariance on the…

Statistics Theory · Mathematics 2015-06-19 Graham Cox

Bulk peculiar flows are commonplace in the universe, with many surveys reporting their presence on scales spanning between few hundred and several hundred Mpc. However, the sizes and the speeds of some of these bulk flows are well in excess…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Christos G. Tsagas

The mass density field as extracted from peculiar velocities in our cosmological neighborhood is mapped back in time to the CMB in two ways. First, the density power spectrum ($P_k$) is translated into a temperature angular power spectrum…

Astrophysics · Physics 2016-08-30 S. Zaroubi , N. Sugiyama , J. Silk , Y. Hoffman , A. Dekel

A variable speed of light (VSL) cosmology is described in which the causal mechanism of generating primordial perturbations is achieved by varying the speed of light in a primordial epoch. This yields an alternative to inflation for…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-21 J. W. Moffat

In this work, a central-moment-based discrete Boltzmann method (CDBM) is constructed for fluid flows with variable specific heat ratios. The central kinetic moments are employed to calculate the equilibrium discrete velocity distribution…

Fluid Dynamics · Physics 2025-02-25 Chuandong Lin , Xianli Su , Linlin Fei , Kai Hong Luo

We use the optimised skew-spectrum as well as the skew-spectra associated with the Minkowski Functionals (MFs) to test the possibility of using the cross-correlation of the Integrated Sachs-Wolfe effect (ISW) and lensing of the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 D. Munshi , B. Hu , A. Renzi , A. Heavens , P. Coles

The Cosmological Problem is considered in a five-dimensional (bulk) manifold with two time coordinates, obeying vacuum Einstein field equations. The evolution formalism is used there, in order to get a simple form of the resulting…

General Relativity and Quantum Cosmology · Physics 2019-02-27 Carles Bona , Miguel Bezares , Bartolomé Pons-Rullan , Daniele Viganò

The observational behavior of spherically symmetric inhomogeneous cosmological models is studied, which consist of inner and outer homogeneous regions connected by a shell or an intermediate self-similar region. It is assumed that the…

Astrophysics · Physics 2009-10-31 Kenji Tomita

The classical trajectories for FLRW universe with varying speed of light are obtained for the cases in which the cosmological constant depends or not depend on the velocity of light. The theory is then quantized and the corresponding WDW…

General Relativity and Quantum Cosmology · Physics 2010-01-25 F. Shojai , S. Molladavoudi

We present a machine learning approach using normalising flows for inferring cosmological parameters from gravitational wave events. Our methodology is general to any type of compact binary coalescence event and cosmological model and…

General Relativity and Quantum Cosmology · Physics 2023-10-26 Federico Stachurski , Christopher Messenger , Martin Hendry

We study the large-scale velocity fields traced by galaxy clusters in numerical simulations of a box of side 960 $h^{-1}$ Mpc, and compare them with available data on real clusters. In order to test the reliability of the simulations, which…

Fast heuristically weighted, or pseudo-C_l, estimators are a frequently used method for estimating power spectra in CMB surveys with large numbers of pixels. Recently, Challinor & Chon showed that the E-B mixing in these estimators can…

Astrophysics · Physics 2011-04-11 Kendrick M. Smith

Peculiar velocities, obtained from direct distance measurements, are data of choice to achieve constrained simulations of the Local Universe reliable down to a scale of a few Megaparsecs. Unlike redshift surveys, peculiar velocities are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jenny G. Sorce , Helene M. Courtois , Stefan Gottloeber , Yehuda Hoffman , R. Brent Tully

Peculiar velocities in the nearby Universe can be measured via the kinetic Sunyaev-Zel'dovich (kSZ) effect. Using a statistical method based on an optimised cross-correlation with nearby galaxies, we extract the kSZ signal generated by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Guilhem Lavaux , Niayesh Afshordi , Michael J. Hudson
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