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The existence of 'peculiar' velocities due to the formation of cosmic structure marks a point of discord between the real Universe and the usually assumed Friedmann-Lema\'{i}tre-Robertson-Walker metric which accomodates only the smooth…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-09 Roya Mohayaee , Mohamed Rameez , Subir Sarkar

We present a new method for the reconstruction of Sunyaev-Zel'dovich (SZ) galaxy clusters in future SZ-survey experiments using multiband bolometer cameras such as Olimpo, APEX, or Planck. Our goal is to optimise SZ-Cluster extraction from…

Astrophysics · Physics 2009-11-11 S. Pires , J. B. Juin , D. Yvon , Y. Moudden , S. Anthoine , E. Pierpaoli

We introduce a new technique for following the formation and evolution of galaxies in cosmological N-body simulations. Dissipationless simulations are used to track the formation and merging of dark matter halos as a function of redshift.…

There are two redshifts in cosmology: $z_{obs}$, the observed redshift computed via spectral lines, and the model redshift, $z$, defined by the effective FLRW scale factor. In general these do not coincide. We place observational…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-06 Bruce A. Bassett , Yabebal Fantaye , Renée Hložek , Cristiano Sabiu , Mat Smith

Future ground-based CMB experiments will generate competitive large-scale structure datasets by precisely characterizing CMB secondary anisotropies over a large fraction of the sky. We describe a method for constraining the growth rate of…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 David Alonso , Thibaut Louis , Philip Bull , Pedro G. Ferreira

We present a Bayesian reconstruction method which maps a galaxy distribution from redshift-space to real-space inferring the distances of the individual galaxies. The method is based on sampling density fields assuming a lognormal prior…

We use observations and simulation to study the relationship between star-forming galaxies and the intergalactic medium at z~3. The observed galaxy sample is based on spectroscopic redshift data from a combination of the VLT LBG Redshift…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 P. Tummuangpak , R. Bielby , T. Shanks , N. H. M. Crighton , H. Francke , L. Infante , T. Theuns

We develop a method for reconstructing the two-dimensional, projected gravitational potential of galaxy clusters from observed line-of-sight velocity dispersions of cluster galaxies. It is the third of an intended series of papers aiming at…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Eleonora Sarli , Sven Meyer , Massimo Meneghetti , Sara Konrad , Charles L. Majer , Matthias Bartelmann

The Sunyaev-Zel'dolvich (SZ) effect is expected to be instrumental in measuring velocities of distant clusters in near future telescope surveys. We simplify the calculation of peculiar velocities of galaxy clusters using deep learning…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 Yuyu Wang , Nesar Ramachandra , Edgar M. Salazar-Canizales , Hume A. Feldman , Richard Watkins , Klaus Dolag

Currently, existing tensor recovery methods fail to recognize the impact of tensor scale variations on their structural characteristics. Furthermore, existing studies face prohibitive computational costs when dealing with large-scale…

Machine Learning · Computer Science 2025-07-09 Wenjin Qin , Hailin Wang , Jingyao Hou , Jianjun Wang

We systematically study the effects of varying the starting redshift z_i for cosmological simulations in the highly non-linear regime. Our primary focus lies with the (individual) properties of dark matter halos -- namely the mass, spin,…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Alexander Knebe , Christian Wagner , Steffen Knollmann , Tobias Diekershoff , Fabian Krause

Using comoving distance $d_c$ and angular diameter distance $d_A$, we recalculate parameters describing kinematical state of the universe, still combining the kinematical model of universe but not relying on dynamical equations for gravity.…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-27 Hai Huang , Long Huang

Using a dynamical 3-D reconstruction procedure we estimate the peculiar velocities of $R\ge0$ Abell/ACO galaxy clusters from their measured redshift within 25000 km/sec. The reconstruction algorithm relies on the linear gravitational…

Astrophysics · Physics 2009-10-28 Enzo Branchini , Manolis Plionis , Dennis W. Sciama

We perform the first joint analysis of galaxy clustering (GC) and the kinetic Sunyaev-Zel'dovich (kSZ) effect to simultaneously constrain cosmological and astrophysical parameters in this work, utilizing a combination of the Atacama…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-13 Shaohong Li , Yi Zheng

The redshifts of ~250000 galaxies are used to study the Local Hole and its associated peculiar velocities. The sample, compiled from 6dFGS and SDSS provides wide sky coverage to a depth of ~300h-1Mpc. We have therefore examined K and r…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-07 J. R. Whitbourn , T. Shanks

When measuring the value of the Hubble parameter, $H_0$, it is necessary to know the recession velocity free of the effects of peculiar velocities. In this work, we study different models of peculiar velocity in the local Universe. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Supranta S. Boruah , Michael J. Hudson , Guilhem Lavaux

The theoretical basis of dark energy remains unknown and could signify a need to modify the laws of gravity on cosmological scales. In this study we investigate how the clustering and motions of galaxies can be used as probes of modified…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-10 Stuart Lyall , Chris Blake , Ryan Turner , Rossana Ruggeri , Hans Winther

A method we developed recently for the reconstruction of the initial density field in the nearby Universe is applied to the Sloan Digital Sky Survey Data Release 7. A high-resolution N-body constrained simulation (CS) of the reconstructed…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-15 Huiyuan Wang , H. J. Mo , Xiaohu Yang , Youcai Zhang , JingJing Shi , Y. P. Jing , Chengze Liu , Shijie Li , Xi Kang , Yang Gao

The caustic technique uses galaxy redshifts alone to measure the escape velocity and mass profiles of galaxy clusters to clustrocentric distances well beyond the virial radius, where dynamical equilibrium does not necessarily hold. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Ana Laura Serra , Antonaldo Diaferio , Giuseppe Murante , Stefano Borgani

We investigate the possibility of probing dark energy by measuring the isotropy of the galaxy cluster autocorrelation function (an Alcock-Paczynski test). The correlation function is distorted in redshift space because of the cluster…

Astrophysics · Physics 2008-11-26 Young-Rae Kim , Rupert Croft