scholarly journals Cosmological Constraints from Hubble Parameter versus Redshift Data

2006 ◽  
Vol 650 (1) ◽  
pp. L5-L8 ◽  
Author(s):  
Lado Samushia ◽  
Bharat Ratra
Keyword(s):  
Hubble Parameter ◽  
Cosmological Constraints ◽  
Parameter Versus

scholarly journals Cosmological constraints from the Hubble parameter onf(R) cosmologies

2008 ◽  
Vol 2008 (09) ◽  
pp. 008 ◽  
Author(s):  
F C Carvalho ◽  
E M Santos ◽  
J S Alcaniz ◽  
J Santos
Keyword(s):  
Hubble Parameter ◽  
Cosmological Constraints

scholarly journals Relaxion window

2017 ◽  
Vol 32 (27) ◽  
pp. 1750142 ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Osamu Seto ◽  
Takashi Shimomura ◽  
Yuko Urakawa
Keyword(s):  
Strong Correlation ◽  
Hubble Parameter ◽  
Particle Physics ◽  
Large Scale ◽  
Mass Formula ◽  
Scalar Potential ◽  
Mass Range ◽  
Lower Mass ◽  
Cosmological Constraints ◽  
Physics Model

We investigate cosmological constraints on the original relaxion scenario proposed by Graham, Kaplan and Rajendran. We first discuss the appropriate sign choice of the terms in the scalar potential, when the QCD axion is the relaxion with a relaxion–inflaton coupling proposed in the original paper. We next derive the cosmologically consistent ranges of the mass and a coupling of the relaxion for both the QCD relaxion and non-QCD relaxion. The mass range is obtained by [Formula: see text]. We also find that a strong correlation between the Hubble parameter at the relaxion stabilization and the scale [Formula: see text] of non-QCD strong dynamics, which generates the non-perturbative relaxion cosine potential. For a higher relaxion mass, a large scale [Formula: see text] becomes available. However, for its lower mass, [Formula: see text] should be small and constructing such a particle physics model is challenging.

COSMOGRAPHY WITH THE HUBBLE PARAMETER

2011 ◽  
Vol 26 (20) ◽  
pp. 1459-1466 ◽  
Author(s):  
ORLANDO LUONGO
Keyword(s):  
Hubble Parameter ◽  
Free Parameter ◽  
A Priori ◽  
Matter Density ◽  
Cosmological Constraints ◽  
Fitting Procedure ◽  
Model Independent ◽  
The Universe ◽  
Friedmann Robertson Walker

In this paper we investigate the possibility to obtain constraints on the kinematics of the Universe in a flat Friedmann–Robertson–Walker cosmology, through the use of the so-called Cosmography. The basic idea lies directly on fitting the H(z) series, by adopting a more recent dataset of H(z), in the range z≼1.8, obtaining the limits of the kinematical quantities under exam. The advantage that we propose here is that this fitting procedure is model independent and it does not need any assumption given a priori on the cosmology of the Universe, but only its geometry and flatness. Moreover, as an example, we relate the measured cosmographic set to the free parameter of ΛCDM, being the matter density Ωm. In fact, by inverting Ωm in terms of the cosmographic set, it would be possible to infer limits on it. We find results in agreement with other kind of cosmological constraints.

scholarly journals The constraint ability of Hubble parameter by gravitational wave standard sirens on cosmological parameters

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Tong-Jie Zhang ◽  
Yang Liu ◽  
Zhi-E Liu ◽  
Hao-Yi Wan ◽  
Ting-Ting Zhang ◽  
...  
Keyword(s):  
Binary System ◽  
Gravitational Wave ◽  
Hubble Parameter ◽  
Figure Of Merit ◽  
Confidence Region ◽  
Cosmological Parameters ◽  
New Method ◽  
Cosmological Constraints ◽  
Einstein Telescope ◽  
Potential Possibility

Abstract In this paper, we present the application of a new method measuring Hubble parameter H(z) by using the anisotropy of luminosity distance ($$d_{L}$$dL) of the gravitational wave (GW) standard sirens of neutron star (NS) binary system. The method has never been put into practice so far due to the lack of the ability of detecting GW. However, LIGO’s success in detecting GW of black hole (BH) binary system merger announced the potential possibility of this new method. We apply this method to several GW detecting projects, including Advanced LIGO (aLIGO), Einstein Telescope (ET) and DECIGO, and evaluate its constraint ability on cosmological parameters of H(z). It turns out that the H(z) by aLIGO and ET is of bad accuracy, while the H(z) by DECIGO shows a good one. We simulate H(z) data at every 0.1 redshift span using the error information of H(z) by DECIGO, and put the mock data into the forecasting of cosmological parameters. Compared with the previous data and method, we get an obviously tighter constraint on cosmological parameters by mock data, and a concomitantly higher value of Figure of Merit (FoM, the reciprocal of the area enclosed by the $$2\sigma $$2σ confidence region). For a 3-year-observation by standard sirens of DECIGO, the FoM value is as high as 170.82. If a 10-year-observation is launched, the FoM could reach 569.42. For comparison, the FoM of 38 actual observed H(z) data (OHD) is 9.3. We also investigate the undulant universe, which shows a comparable improvement on the constraint of cosmological parameters. These improvement indicates that the new method has great potential in further cosmological constraints.

The uncertainty principle between the Hubble parameter and the volume of space.

2019 ◽  
Author(s):  
Vitaly Kuyukov
Keyword(s):  
Uncertainty Principle ◽  
Hubble Parameter

The uncertainty principle between the Hubble parameter and the volume of space.

scholarly journals Towards a self-consistent analysis of the anisotropic galaxy two- and three-point correlation functions on large scales: application to mock galaxy catalogues

2020 ◽  
Author(s):  
Naonori S Sugiyama ◽  
Shun Saito ◽  
Florian Beutler ◽  
Hee-Jong Seo
Keyword(s):  
Correlation Functions ◽  
Hubble Parameter ◽  
Theoretical Models ◽  
Practical Method ◽  
Acoustic Oscillation ◽  
Nonlinear Damping ◽  
Joint Analysis ◽  
Angular Diameter Distance ◽  
Point Correlation ◽  
Parameter Constraints

Abstract We establish a practical method for the joint analysis of anisotropic galaxy two- and three-point correlation functions (2PCF and 3PCF) on the basis of the decomposition formalism of the 3PCF using tri-polar spherical harmonics. We perform such an analysis with MultiDark Patchy mock catalogues to demonstrate and understand the benefit of the anisotropic 3PCF. We focus on scales above 80 h−1 Mpc, and use information from the shape and the baryon acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density field reconstruction to increase the signal-noise ratio of BAO in the 2PCF measurement, but not in the 3PCF measurement. In particular, we study in detail the constraints on the angular diameter distance and the Hubble parameter. We build a model of the bispectrum or 3PCF that includes the nonlinear damping of the BAO signal in redshift space. We carefully account for various uncertainties in our analysis including theoretical models of the 3PCF, window function corrections, biases in estimated parameters from the fiducial values, the number of mock realizations to estimate the covariance matrix, and bin size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole components shows a $30\%$ and $20\%$ improvement in Hubble parameter constraints before and after reconstruction of the 2PCF measurements, respectively, compared to the 2PCF analysis alone. This study clearly shows that the anisotropic 3PCF increases cosmological information from galaxy surveys and encourages further development of the modeling of the 3PCF on smaller scales than we consider.

Deep learning approach to Hubble parameter

2021 ◽  
Vol 261 ◽  
pp. 107809
Author(s):  
H. Tilaver ◽  
M. Salti ◽  
O. Aydogdu ◽  
E.E. Kangal
Keyword(s):  
Deep Learning ◽  
Hubble Parameter ◽  
Learning Approach

scholarly journals Redshift-space effects in voids and their impact on cosmological tests. Part I: the void size function

2020 ◽  
Vol 500 (1) ◽  
pp. 911-925
Author(s):  
Carlos M Correa ◽  
Dante J Paz ◽  
Ariel G Sánchez ◽  
Andrés N Ruiz ◽  
Nelson D Padilla ◽  
...  
Keyword(s):  
Theoretical Framework ◽  
Real Space ◽  
Global Dynamics ◽  
Void Size ◽  
Spherical Void ◽  
Cosmological Constraints ◽  
Redshift Surveys ◽  
Size Function ◽  
Expansion Effect ◽  
Space Effects

ABSTRACT Voids are promising cosmological probes. Nevertheless, every cosmological test based on voids must necessarily employ methods to identify them in redshift space. Therefore, redshift-space distortions (RSD) and the Alcock–Paczyński effect (AP) have an impact on the void identification process itself generating distortion patterns in observations. Using a spherical void finder, we developed a statistical and theoretical framework to describe physically the connection between the identification in real and redshift space. We found that redshift-space voids above the shot noise level have a unique real-space counterpart spanning the same region of space, they are systematically bigger and their centres are preferentially shifted along the line of sight. The expansion effect is a by-product of RSD induced by tracer dynamics at scales around the void radius, whereas the off-centring effect constitutes a different class of RSD induced at larger scales by the global dynamics of the whole region containing the void. The volume of voids is also altered by the fiducial cosmology assumed to measure distances, this is the AP change of volume. These three systematics have an impact on cosmological statistics. In this work, we focus on the void size function. We developed a theoretical framework to model these effects and tested it with a numerical simulation, recovering the statistical properties of the abundance of voids in real space. This description depends strongly on cosmology. Hence, we lay the foundations for improvements in current models of the abundance of voids in order to obtain unbiased cosmological constraints from redshift surveys.

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