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Spatial processes with nonstationary and anisotropic covariance structure are often used when modelling, analysing and predicting complex environmental phenomena. Such processes may often be expressed as ones that have stationary and…

Methodology · Statistics 2020-04-06 Andrew Zammit-Mangion , Tin Lok James Ng , Quan Vu , Maurizio Filippone

The formation and collapse of a protostar involves the simultaneous infall and outflow of material in the presence of magnetic fields, self-gravity, and rotation. We use self-similar techniques to self-consistently model the anisotropic…

Astrophysics · Physics 2016-01-13 Mahmoud Aburihan , Jason D. Fiege , Richard N. Henriksen , Thibaut Lery

We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-19 Mathias Garny , Thomas Konstandin , Rafael A. Porto , Laura Sagunski

We have studied the nonlinear structure formation of the environmentally dependent dilaton model using $N$-body simulations. We find that the mechanism of suppressing the scalar fifth force in high-density regions works very well. Within…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Phil Brax , Carsten van de Bruck , Anne-C. Davis , Baojiu Li , Douglas J. Shaw

We present direct $N$-body simulations of tidally filling 30,000 ${\rm M}_\odot$ star clusters orbiting between 10 kpc and 100 kpc in galaxies with a range of dark matter substructure properties. The time-dependent tidal force is determined…

Astrophysics of Galaxies · Physics 2019-08-21 Jeremy J. Webb , Jo Bovy , Raymond G. Carlberg , Mark Gieles

Most prior works studying tidal interactions in tight star/planet or star/star binary systems have employed linear theory of a viscous fluid in a uniformly-rotating two-dimensional spherical shell. However, compact systems may have…

Solar and Stellar Astrophysics · Physics 2023-10-11 Aurélie Astoul , Adrian J. Barker

In this paper we calculate the particle creation as seen by a stationary observer in an anisotropic universe. By using an observer and geometry dependent time to quantise a massive scalar field we show that a discrete energy spectrum shift…

High Energy Physics - Theory · Physics 2009-10-28 D. J. Lamb , A. Z. Capri , M. Kobayashi

Upcoming large-scale structure surveys will measure the matter power spectrum to approximately percent level accuracy with the aim of searching for evidence for new physics beyond the standard model of cosmology. In order to avoid biasing…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-18 Jaime Salcido , Ian G. McCarthy , Juliana Kwan , Amol Upadhye , Andreea S. Font

We apply CMB lensing techniques to large scale structure and solve for the 3-D cosmic tidal field. We use small scale filamentary structures to solve for the large scale tidal shear and gravitational potential. By comparing this to the…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-28 Ue-Li Pen , Ravi Sheth , J. Harnois-Deraps , Xuelei Chen , Zhigang Li

This work deals with the computation of the power spectrum of large-scale structure using the dynamical system approach for a multi-fluid universe in scalar-tensor theory of gravity. We use the $1+3$ covariant approach to obtain evolution…

General Relativity and Quantum Cosmology · Physics 2022-08-31 Joseph Ntahompagaze , Amare Abebe , Manasse R. Mbonye

Tidal dissipation, which is directly linked to internal structure, is one of the key physical mechanisms that drive systems evolution and govern their architecture. A robust evaluation of its amplitude is thus needed to predict evolution…

Earth and Planetary Astrophysics · Physics 2014-12-10 F. Remus , S. Mathis , J. -P. Zahn , V. Lainey

In weakly collisional stellar systems such as some globular clusters, partial energy equipartition and mass segregation are expected to develop as a result of the cumulative effect of stellar encounters even in systems initially…

Astrophysics of Galaxies · Physics 2019-12-04 Stefano Torniamenti , Giuseppe Bertin , Paolo Bianchini

We study the local response to long wavelength fluctuations in cosmological $N$-body simulations, focusing on the matter and halo power spectra, halo abundance and non-linear transformations of the density field. The long wavelength mode is…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Tobias Baldauf , Uroš Seljak , Leonardo Senatore , Matias Zaldarriaga

A new time-dependent, scale-independent parameter, \varpi, is employed in a phenomenological model of the deviation from General Relativity in which the Newtonian and longitudinal gravitational potentials slip apart on cosmological scales…

Astrophysics · Physics 2008-11-26 Scott F. Daniel , Robert R. Caldwell , Asantha Cooray , Alessandro Melchiorri

Most existing cosmological entanglement studies are focused on the isotropic Robertson-Walker (RW) spacetime. Here we go beyond this limitation and study the influence of anisotropy on entanglement generated by dynamical spacetime. Since…

General Relativity and Quantum Cosmology · Physics 2017-11-16 Roberto Pierini , Shahpoor Moradi , Stefano Mancini

The Large-Scale Structure (LSS) of the Universe provides valuable information for modern cosmology. The future redshift surveys, as DESI (Dark Energy Spectroscopic Instrument), will measure millions of galaxies and quasars, which allows to…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-27 Dante V. Gomez-Navarro

It is known than the inclusion of spatial curvature can modify the evolution of matter perturbations and affect the Large Scale Structure (LSS) formation. We quantify the effects of the non-zero space curvature in terms of LSS formation for…

General Relativity and Quantum Cosmology · Physics 2020-12-08 Jhonny A. Agudelo Ruiz , Júlio C. Fabris , Alan M. Velasquez-Toribio , Ilya L. Shapiro

Redshift-space clustering anisotropies caused by cosmic peculiar velocities provide a powerful probe to test the gravity theory on large scales. However, to extract unbiased physical constraints, the clustering pattern has to be modelled…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-28 Federico Marulli , Alfonso Veropalumbo , Lauro Moscardini , Andrea Cimatti , Klaus Dolag

It is common practice, both in dynamical modelling and in idealised numerical simulations, to assume that galaxies and/or dark matter haloes are spherical and have isotropic velocity distributions, such that their distribution functions are…

Astrophysics of Galaxies · Physics 2025-11-04 Barry T. Chiang , Frank C. van den Bosch , Hsi-Yu Schive

The ghost-free theory of massive gravity with two dynamical metrics has been shown to produce viable cosmological expansion, where the late-time acceleration of the Universe is due to the finite range of the gravitational interaction rather…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-29 Adam R. Solomon , Yashar Akrami , Tomi S. Koivisto