English
Related papers

Related papers: Cosmological number density in depth from V/Vm dis…

200 papers

Using distribution p(V/Vm) of V/Vm rather than just mean <V/Vm> in V/Vm-test leads directly to cosmological number density n(z). Calculation of n(z) from p(V/Vm) is illustrated using best sample (of 76 quasars) available in 1981, when…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-17 Dilip G. Banhatti

The classical cosmological V/Vm-test is introduced. Use of the differential distribution p(V/Vm) of the V/Vm-variable rather than just the mean <V/Vm> leads directly to the cosmological number density without any need for assumptions about…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-12 Dilip G. Banhatti

The classical cosmological V/Vm-test is introduced and elaborated. Use of the differential distribution p(V/Vm) of the V/Vm-variable rather than just the mean <V/Vm> leads directly to the cosmological number density without any need for…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-09 Dilip G. Banhatti

Banhatti (2009) set down the procedure to derive cosmological number density n(z) from the differential distribution p(x) of the fractional luminosity volume relative to the maximum volume, x \equiv V/Vm (0 \leq x \leq 1), using a small…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-03 Dilip G Banhatti

A new cosmological test is derived, based on the distribution of individual V/Vmax in a complete redshift-limited sample of distant objects. The fundamental assumption is that, in any bin of absolute luminosity, individual V/Vmax are…

Astrophysics · Physics 2007-05-23 L. Van Waerbeke , G. Mathez , Y. Mellier , H. Bonnet , M. Lachieze-Rey

Although the $\Lambda$ Cold Dark Matter model is the most accredited cosmological model, information at high redshifts ($z$) between type Ia supernovae ($z=2.26$) and the Cosmic Microwave Background ($z=1100$) is crucial to validate this…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-23 Maria Giovanna Dainotti , Giada Bargiacchi , Aleksander Łukasz Lenart , Salvatore Capozziello

The value of the cosmological constant arising from a crystalline model for vacuum cosmic space with lattice parameter of the order of the neutron radius [1] has been calculated. The model allows to solve, in an easy way, the problem of the…

The challenge of understanding the Universe's dynamics, particularly the Hubble tension, requires precise measurements of the Hubble constant. Building upon the existing spectral-siren method, which capitalizes on population information…

General Relativity and Quantum Cosmology · Physics 2025-01-10 Thomas C. K. Ng , Stefano Rinaldi , Otto A. Hannuksela

Void number counts (VNC) indicates the number of low-density regions in the large-scale structure (LSS) of the Universe, and we propose to use it as an effective cosmological probe. By generating the galaxy mock catalog based on Jiutian…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-06 Yingxiao Song , Qi Xiong , Yan Gong , Furen Deng , Kwan Chuen Chan , Xuelei Chen , Qi Guo , Yun Liu , Wenxiang Pei

The Friedmann equation is derived for a Newtonian universe. Changing mass density to energy density gives exactly the Friedmann equation of general relativity. Accounting for work done by pressure then yields the two Einstein equations that…

Astrophysics · Physics 2015-06-24 Thomas F. Jordan

We examine a simple theoretical model to estimate (by fine tuning condition) the value of the cosmological constant. We assume, in analogy with holographic principle, that cosmological constant, like classical surface tension coefficient in…

Astrophysics · Physics 2008-01-21 V. Pankovic , S. Ciganovic , J. Ivanovic , R. Glavatovic , P. Grujic

In theories in which the cosmological constant Lambda takes a variety of values in different ``subuniverses,'' the probability distribution of its observed values is conditioned by the requirement that there must be someone to measure it.…

Astrophysics · Physics 2009-10-30 Hugo Martel , Paul R. Shapiro , Steven Weinberg

A crucial test of any cosmological model is the distribution of distant objects such as quasars. Because of well defined selection criteria quasars found by a ultraviolet excess (UVX) survey are ideal candidates for testing the model out to…

Astrophysics · Physics 2009-10-22 David F. Crawford

Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent…

High Energy Physics - Phenomenology · Physics 2009-10-28 Anupam Singh

Within the $\Lambda$CDM cosmological model, the absolute value of Einstein's cosmological constant $\Lambda$, sometimes expressed as the gravitating mass-energy density $\rho_\Lambda$ of the physical vacuum, is a fundamental constant of…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-22 J. Prat , C. Hogan , C. Chang , J. Frieman

The statistical properties of cosmic structures are well known to be strong probes for cosmology. In particular, several studies tried to use the cosmic void counting number to obtain tight constrains on Dark Energy. In this paper we…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 Jean-Michel Alimi , Paul de Fromont

Counts-in-cells are measured in the $\tau$CDM Virgo Hubble Volume simulation. This large N-body experiment has 10^9 particles in a cubic box of size 2000 h^{-1} Mpc. The unprecedented combination of size and resolution allows for the first…

Astrophysics · Physics 2009-10-31 Stéphane Colombi , István Szapudi , Adrian Jenkins , Jörg Colberg

In this work a satisfactory, simple theoretical prediction of the data corresponding to observationally (by fine tuning condition) estimated value of the cosmological constant is given. It is supposed (in conceptually analogy with…

Astrophysics · Physics 2007-12-27 Vladan Pankovic , Simo Ciganovic , Jovan Ivanovic , Rade Glavatovic , Petar Grujic

We propose a new approach to understand hierarchy problem for cosmological constant in terms of considering noncommutative nature of space-time. We calculate that vacuum energy density of the noncommutative quantum field theories in…

High Energy Physics - Theory · Physics 2007-05-23 Xiao-Jun Wang

This work is related to different questions within cosmology. The principal idea herein is to develop cosmological knowledge making use of the analyses of observational data in order to find the values of the matter density Omega_m and…

Astrophysics · Physics 2007-05-23 S. M. Harun-or-Rashid
‹ Prev 1 2 3 10 Next ›