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{We study in some details the statistical properties of the turbulent 2-phase interstellar atomic gas.{We present high resolution bidimensional numerical simulations of the interstellar atomic hydrogen which describe it over 3 to 4 orders…

Astrophysics · Physics 2015-06-24 P. Hennebelle , E. Audit

Hydrodynamical simulations indicate that substantial fraction of baryons in the Universe remains in a diffuse component - Warm-Hot Intergalactic Medium (WHIM). To determine physical properties (spatial distribution, temperature and density)…

Astrophysics · Physics 2009-11-11 Andrzej M. Soltan

We present the power spectrum analysis of clustering in the Durham/UKST Galaxy Redshift Survey, which covers 1450 square degrees and consists of 2501 galaxy redshifts sampled at a rate of 1 in 3 to b_J = 17. The fluctuations that we measure…

Astrophysics · Physics 2009-10-31 F. Hoyle , C. M. Baugh , T. Shanks , A. Ratcliffe

Visibility scintillation resulting from wave propagation through the turbulent ionosphere can be an important sources of noise at low radio frequencies ($\nu\lesssim 200$ MHz). Many low frequency experiments are underway to detect the power…

Instrumentation and Methods for Astrophysics · Physics 2016-03-16 H. K. Vedantham , L. V. E. Koopmans

We apply the methods of Field Theory to study the turbulent regimes of statistical systems. First we show how one can find their probability densities. For the case of the theory of wave turbulence with four-wave interaction we calculate…

High Energy Physics - Theory · Physics 2009-10-28 V. Gurarie

Aims: To showcase and characterise the rich phenomenology of temperature fluctuation patterns that are imprinted on the CMB by the gravitational wave memory (GWM) of massive black hole (BH) mergers. Methods: We analyse both individual…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Lorenz Zwick , David O'Neill , Kai Hendriks , Philip Kirkeberg , Miquel Miravet-Tenés

Turbulent flows are ubiquitous in astrophysical environments, and understanding density structures and their statistics in turbulent media is of great importance in astrophysics. In this paper, we study the density power spectra,…

Astrophysics · Physics 2009-11-11 Jongsoo Kim , Dongsu Ryu

Geometric characteristics of random fields are exploited to test the consistency of density perturbation model spectra with COBE data. These CMB maps are analyzed using the number of anisotropy hot spots and their boundary curvature. CMB…

Astrophysics · Physics 2008-02-03 Sergio Torres

The latest cosmological observables analyses seem to converge to a concordant view of the cosmological model: namely the power law Lambda-CDM. The recent WMAP results comfort this new standard model. Nevertheless, some degeneracy in the CMB…

Astrophysics · Physics 2007-05-23 Marian Douspis

We present astrophysical applications of the recently popular halo model to describe large scale structure clustering. We formulate the power spectrum, bispectrum and trispectrum of dark matter density field in terms of correlations within…

Astrophysics · Physics 2007-05-23 Asantha Cooray

We compute the two-point angular correlation function $w(\theta)$ for a sample of $\sim$ 1700 galaxies to a magnitude-limit equivalent to $R \sim 29.5$ using a catalog derived from the Hubble Deep Field images. A non zero value of…

Astrophysics · Physics 2009-10-28 Jens V. Villumsen , Wolfram Freudling , Luiz N. da Costa

We study the effect of dark matter (DM) being encapsulated in primordial black holes (PBHs) on the power spectrum of density fluctuations $P(k)$; we also look at its effect on the abundance of haloes and their clustering. We allow the…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-28 Nelson Padilla , Juan Magana , Joaquin Sureda , Ignacio Araya

We study fluctuations of the local energy cascade rate $\Phi_\ell$ in turbulent flows at scales ($\ell$) in the inertial range. According to the Kolmogorov refined similarity hypothesis (KRSH), relevant statistical properties of $\Phi_\ell$…

Fluid Dynamics · Physics 2024-04-29 H. Yao , P. K. Yeung , T. A. Zaki , C. Meneveau

We suggest to use the common appearance of voids with a scale of $5000 \kms$ in the galaxy distribution to estimate the power spectrum on this scale. We use a simple model for a gravitational formation of voids and we compare the results…

Astrophysics · Physics 2008-02-03 T. Piran , M. Lecar , D. S. Goldwirth , L. Nicolaci da Costa , G. R. Blumenthal

The Parkes telescope has been monitoring 286 radio pulsars approximately monthly since 2007 at an observing frequency of 1.4 GHz. The wide dispersion measure (DM) range of the pulsar sample and the uniformity of the observing procedure make…

High Energy Astrophysical Phenomena · Physics 2021-01-06 H. Kumamoto , S. Dai , S. Johnston , M. Kerr , R. M. Shannon , P. Weltevrede , C. Sobey , R. N. Manchester , G. Hobbs , K. Takahashi

Bose-Einstein condensates with their superfluidity property provide an interesting parallel to classical fluids. Due to the Kolmogorov spectrum of homogeneous turbulence the statistics of the incompressible velocity field is of great…

Quantum Gases · Physics 2022-08-16 Marcos A. G. dos Santos Filho , Francisco E. A. dos Santos

Gravitational wave (GW) data from observed binary black hole coalescences (BBHC) have been demonstrated in recent analyses to validate the Hawking Area Theorem (HAT) for black hole horizons. The result of such analyses is imposed here as a…

General Relativity and Quantum Cosmology · Physics 2026-02-05 Parthasarathi Majumdar

In the study of weakly turbulent wave systems possessing incomplete self-similarity it is possible to use dimensional arguments to derive the scaling exponents of the Kolmogorov-Zakharov spectra, provided the order of the resonant wave…

Fluid Dynamics · Physics 2009-11-10 Colm Connaughton , Sergey Nazarenko , Alan C. Newell

We propose a new signature for weakly interacting massive particle (WIMP) dark matter, a spectral feature in the diffuse extragalactic gamma-ray radiation. This feature, a sudden drop of the gamma-ray intensity at an energy corresponding to…

Astrophysics · Physics 2010-04-06 Lars Bergstrom , Joakim Edsjo , Piero Ullio

A wave turbulence theory is developed for inertial electron magnetohydrodynamics (IEMHD) in the presence of a relatively strong and uniform external magnetic field $\boldsymbol{B_0} = B_0 \hat{\boldsymbol{e}}_\|$. This regime is relevant…

Plasma Physics · Physics 2022-10-26 Vincent David , Sébastien Galtier