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Galaxy clusters are potentially powerful probes of the large-scale velocity field in the Universe because their peculiar velocity can be estimated directly via the kinematic Sunyaev-Zeldovich effect (kSZ). Using high-resolution cosmological…

Astrophysics · Physics 2011-05-12 Daisuke Nagai , Andrey V. Kravtsov , Arthur Kosowsky

We derive new approximations for quintessence solutions that are simpler and an order of magnitude more accurate than anything available in the literature, which from an observational perspective \emph{makes numerical calculations…

General Relativity and Quantum Cosmology · Physics 2025-05-06 Artur Alho , Claes Uggla

We present an analysis of the parallel peculiar velocity correlation function using data from the Cosmicflows-4 (CF4) survey. CF4 significantly extends the depth of the peculiar velocity measurements, mitigating the impact of observers on…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-10 Yuyu Wang , Hume A. Feldman , Richard Watkins , Xiaohu Yang

A powerful test of fundamental physics consists on probing the variability of fundamental constants in Nature. Although they have been measured on Earth laboratories and in our Solar neighbourhood with extremely high precision, it is…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-27 Gabriel Rodrigues , Carlos Bengaly

We assess the effect of the local large scale structure on the estimation of two-point statistics of the observed radial peculiar velocities of galaxies. A large N-body simulation is used to examine these statistics from the perspective of…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 Wojciech A. Hellwing , Adi Nusser , Martin Feix , Maciej Bilicki

The Poisson point process (PPP) is not always a realistic model for the locations of vehicles along a road, because it does not account for the safety distance a driver maintains from the vehicle ahead. In this paper, we model the…

Networking and Internet Architecture · Computer Science 2020-09-11 Konstantinos Koufos , Carl P. Dettmann

A common way to quantify the ,,distance'' between measures is via their discrepancy, also known as maximum mean discrepancy (MMD). Discrepancies are related to Sinkhorn divergences $S_\varepsilon$ with appropriate cost functions as…

Optimization and Control · Mathematics 2020-08-25 Sebastian Neumayer , Gabriele Steidl

We investigate the error implied by the use of the Zel'dovich approximation to set up the initial conditions at a finite redshift zi in numerical simulations. Using a steepest-descent method developed in a previous work we derive the…

Astrophysics · Physics 2009-11-07 P. Valageas

The statistical distribution of the radial pairwise peculiar velocity of galaxies is known to have an exponential form as implied by observations and explicitly shown in N-body simulations. Here we calculate its statistical distribution…

Astrophysics · Physics 2009-10-30 Naoki Seto , Jun'ichi Yokoyama

Photometric redshifts are a key component of many science objectives in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). In this paper, we describe and compare the codes used to compute photometric redshifts for HSC-SSP, how we…

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

We describe a new method for measuring the true redshift distribution of any set of objects studied only photometrically. The angular cross-correlation between objects in a photometric sample with objects in some spectroscopic sample as a…

Astrophysics · Physics 2009-11-13 Jeffrey A. Newman

Optimal transport distances are powerful tools to compare probability distributions and have found many applications in machine learning. Yet their algorithmic complexity prevents their direct use on large scale datasets. To overcome this…

Machine Learning · Statistics 2021-10-14 Kilian Fatras , Younes Zine , Rémi Flamary , Rémi Gribonval , Nicolas Courty

Cosmological peculiar velocities have traditionally been studied within the framework of Newtonian theory. Around the turn of the century, a few quasi-Newtonian analyses appeared in the literature, but led to equations and results identical…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Christos G. Tsagas

We study the extreme $L_p$ discrepancy of infinite sequences in the $d$-dimensional unit cube, which uses arbitrary sub-intervals of the unit cube as test sets. This is in contrast to the classical star $L_p$ discrepancy, which uses…

Number Theory · Mathematics 2021-09-15 Ralph Kritzinger , Friedrich Pillichshammer

The distribution of pairwise, relative peculiar velocities, $f(u;r)$, on small nonlinear scales, $r$, is derived from the Press--Schechter approach. This derivation assumes that Press--Schechter clumps are virialized and isothermal. The…

Astrophysics · Physics 2015-06-24 Ravi K. Sheth , U. C. Berkeley

To date, the most precise measurement of the observer's peculiar velocity comes from the dipole in the Cosmic Microwave Background (CMB). This velocity also generates a dipole in the source number counts, whose amplitude is governed not…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-27 Fabien Lacasa , Camille Bonvin , Charles Dalang , Ruth Durrer

The need for accurate photometric redshifts estimation is a topic that has fundamental importance in Astronomy, due to the necessity of efficiently obtaining redshift information without the need of spectroscopic analysis. We propose a…

Instrumentation and Methods for Astrophysics · Physics 2017-06-14 Antonio D'Isanto

Existing approaches to depth or disparity estimation output a distribution over a set of pre-defined discrete values. This leads to inaccurate results when the true depth or disparity does not match any of these values. The fact that this…

Computer Vision and Pattern Recognition · Computer Science 2021-03-30 Divyansh Garg , Yan Wang , Bharath Hariharan , Mark Campbell , Kilian Q. Weinberger , Wei-Lun Chao

We investigate the distance-redshift relation in a realistic inhomogeneous universe where the mass distribution is described by the mass function of Sheth and Tormen. It is found that the derived distance deviates systematically from the…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-19 Tomohiro Okamura , Toshifumi Futamase
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