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Growth of the structure in the Universe manifest as accretion flows of galaxies onto groups and clusters. Thus, the present day properties of groups and their member galaxies are influenced by the characteristics of this continuous infall…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 M. V. Santucho , M. L. Ceccarelli , D. G. Lambas

Recent observations of high-redshift Type Ia supernovae have placed stringent constraints on the cosmological constant $\Lambda$. We explore the implications of these SNe observations for cosmological models in which a classically evolving…

Astrophysics · Physics 2009-10-30 Joshua A. Frieman , Ioav Waga

We study different one-parametric models of type Ia Supernova magnitude evolution on cosmic time scales. Constraints on cosmological and Supernova evolution parameters are obtained by combined fits on the actual data coming from Supernovae,…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-16 Sebastian Linden , Jean-Marc Virey , Andre Tilquin

Peculiar velocity surveys, which measure galaxy peculiar velocities directly from standard candles in addition to redshifts, can provide strong constraints on the linear growth rate of cosmological large-scale structure at low redshift. The…

I review the capabilities of H$\alpha$ observations to constrain some aspects of the current models of the interstellar medium. In particular, it is shown that turbulence is a necessary ingredient of any viable model, since most of the…

Astrophysics · Physics 2015-06-24 Andrea Ferrara

Large-scale structure surveys can be used to measure the dipole in the cosmic microwave background (CMB), in the luminosity distances inferred from type-Ia supernova observations, and in the spatial distribution of galaxies and quasars. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Jaiyul Yoo , Matteo Magi , Dragan Huterer

We compare the measured peculiar velocities of 98 local (<150/h Mpc) type Ia supernovae with predictions derived from the PSCz survey. There is excellent agreement between the two datasets with a best fit beta_I (=Omega_m^0.6/b_I) of…

Astrophysics · Physics 2009-11-10 D. J. Radburn-Smith , J. R. Lucey , M. J. Hudson

A strictly linear evolution of the cosmological scale factor is surprisingly an excellent fit to a host of cosmological observations. Any model that can support such a coasting presents itself as a falsifiable model as far as classical…

Astrophysics · Physics 2007-05-23 Savita Gehlaut , A. Mukherjee , S. Mahajan , D. Lohiya

We demonstrate the capability of Principal Component Analysis (PCA) as applied by Heyer & Schloerb (1997) to extract the statistics of turbulent interstellar velocity fields as measured by the energy spectrum, E(k)= k^-beta. Turbulent…

Astrophysics · Physics 2007-05-23 C. Brunt , M. H. Heyer

Peculiar velocities of galaxies hosting Type Ia supernovae generate a significant systematic effect in deriving the dark energy equation of state w, at level of a few percent. Here we illustrate how the peculiar velocity effect in SN Ia…

Astrophysics · Physics 2009-11-13 Alexandra Abate , Ofer Lahav

Under the assumption that they are standard(isable) candles, the lightcurves of Type Ia supernovae have been analyzed in the framework of the standard Friedmann-Lema\^itre-Robertson-Walker cosmology to conclude that the expansion rate of…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-14 Mohamed Rameez

We analyze the cosmic peculiar velocity field as traced by a sample of 1184 spiral, elliptical and S0 galaxies, grouped in 704 objects. We perform a statistical analysis, by calculating the bulk flow, Cosmic Mach Number and velocity…

Astrophysics · Physics 2009-10-22 Lauro Moscardini , Giuseppe Tormen , Sabino Matarrese , Francesco Lucchin

The local Hubble flow provides a valuable probe of the transition between cosmic expansion and nonlinear gravitational dynamics. On large scales, galaxies follow the linear Hubble law, but within group- and cluster-sized environments,…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 David Benisty , Antonino Del Popolo

We study cosmological models using dynamical systems and averaging methods, encompassing flat and open FLRW geometries as well as the LRS Bianchi types I, III, and V. Under mild regularity and frequency-scaling assumptions, we obtain a…

General Relativity and Quantum Cosmology · Physics 2026-01-27 Genly Leon , Claudio Michea

There is mounting observational evidence that the expansion of our Universe is undergoing a late-time acceleration. Among many proposals to describe this phenomenon, the cosmological constant seems to be the simplest and the most natural…

Astrophysics · Physics 2010-03-19 S. Carneiro , C. Pigozzo , H. A. Borges , J. S. Alcaniz

We present a measurement of the velocity flow of the local universe relative to the CMB rest frame, based on the Jha, Riess & Kirshner (2007) sample of 133 low redshift type Ia supernovae. At a depth of 4500 km/s we find a dipole amplitude…

In this methodological note we discuss some details and peculiarities of the cosmic expansion as viewed by a realistic observer. We show that the velocity $v_\Theta$ related to a change (measured by observer's clock) of the angular…

Popular Physics · Physics 2015-06-17 A. V. Toporensky , S. B. Popov

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 physical nature of the very local (<3 Mpc) Hubble flow is studied on the basis of the recent high precision observations in the Local Volume. A model including both analytical treatment and computer simulations describes the flow…

The common attribute of all Big Bang cosmologies is that they are based on the assumption that the universe is expanding. However examination of the evidence for this expansion clearly favours a static universe. The major topics considered…

General Physics · Physics 2014-07-10 David F. Crawford
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