scholarly journals Hubble Diagram Test of Expanding and Static Cosmological Models: The Case for a Slowly Expanding Flat Universe

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Laszlo A. Marosi
Keyword(s):  
Cosmological Models ◽  
Hubble Diagram ◽  
Flat Universe

scholarly journals Infrared Observations of Giant Elliptical Galaxies: (V-K) Colors and the Infrared Hubble Diagram

1980 ◽  
Vol 92 ◽  
pp. 269-277
Author(s):  
Gary L. Grasdalen
Keyword(s):  
Elliptical Galaxies ◽  
Cosmological Models ◽  
Hubble Diagram ◽  
Infrared Observations ◽  
Color Evolution ◽  
Magnitude Diagram ◽  
Luminosity Evolution

The (V-K) colors of giant elliptical galaxies as a function of redshift are discussed. Present data are consistent with mild color evolution at z ~ 0.45. An infrared Hubble (redshift-magnitude) diagram is given. Cosmological models with qo = 0 and no luminosity evolution are clearly excluded by the present data. A wide variety of models including those with qo = 0 are permissible if luminosity evolution is included. Instrumental and programmatic implications of these results are summarized.

scholarly journals SNe Ia Redshift in a Nonadiabatic Universe

Universe ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 104 ◽  
Author(s):  
Rajendra Gupta
Keyword(s):  
Cosmological Constant ◽  
Deceleration Parameter ◽  
Hubble Constant ◽  
Cosmological Models ◽  
Single Parameter ◽  
New Approach ◽  
Cosmological Principle ◽  
Flat Universe ◽  
Λcdm Model ◽  
Two Parameters

By relaxing the constraint of adiabatic universe used in most cosmological models, we have shown that the new approach provides a better fit to the supernovae Ia redshift data with a single parameter, the Hubble constant H0, than the standard ΛCDM model with two parameters, H0 and the cosmological constant Λ related density, ΩΛ. The new approach is compliant with the cosmological principle. It yields the H0 = 68.28 (±0.53) km s−1 Mpc−1 with an analytical value of the deceleration parameter q0 = −0.4. The analysis presented is for a matter-only, flat universe. The cosmological constant Λ may thus be considered as a manifestation of a nonadiabatic universe that is treated as an adiabatic universe.

scholarly journals The gamma-ray bursts Hubble diagram in quintessential cosmological models

2010 ◽  
Vol 411 (2) ◽  
pp. 1213-1222 ◽  
Author(s):  
Marek Demianski ◽  
Ester Piedipalumbo ◽  
Claudio Rubano
Keyword(s):  
Gamma Ray ◽  
Cosmological Models ◽  
Gamma Ray Bursts ◽  
Hubble Diagram

CORRESPONDENCE BETWEEN 5D RICCI-FLAT COSMOLOGICAL MODELS AND QUINTESSENCE DARK ENERGY MODELS

2005 ◽  
Vol 20 (40) ◽  
pp. 3105-3114 ◽  
Author(s):  
LIXIN XU ◽  
HONGYA LIU ◽  
BAORONG CHANG
Keyword(s):  
Dark Energy ◽  
Arbitrary Function ◽  
Big Bang ◽  
Cosmological Models ◽  
Ricci Flat ◽  
Flat Universe ◽  
Energy Models ◽  
Accelerating Expansion ◽  
Big Bounce

We study the accelerating expansion and the induced dark energy of the 5D Ricci-flat universe which is characterized by having a big bounce as opposed to a big bang. We show that the arbitrary function μ(t) contained in the 5D solutions can be rewritten in terms of the redshift z as a new arbitrary function f(z), and we find that there is a correspondence between this f(z) and the potential V(ϕ) of the 4D quintessence models. Using this correspondence, the arbitrary function f(z) and the 5D solution could be specified for a given form of the potential V(ϕ).

scholarly journals Cosmological test with the QSO Hubble diagram

2016 ◽  
Vol 25 (05) ◽  
pp. 1650060 ◽  
Author(s):  
M. López-Corredoira ◽  
F. Melia ◽  
E. Lusso ◽  
G. Risaliti
Keyword(s):  
Cosmological Models ◽  
De Sitter ◽  
Hubble Diagram ◽  
Stellar Objects ◽  
Static Universe ◽  
Steady State Model ◽  
Type Ia ◽  
Nonlinear Relation ◽  
Quasi Stellar Objects ◽  
Ia Supernovae

A Hubble diagram (HD) has recently been constructed in the redshift range [Formula: see text] using a nonlinear relation between the ultraviolet (UV) and X-ray luminosities of quasi stellar objects (QSOs). The Type Ia Supernovae (SN) HD has already provided a high-precision test of cosmological models, but the fact that the QSO distribution extends well beyond the supernova range ([Formula: see text]), in principle provides us with an important complementary diagnostic whose significantly greater leverage in [Formula: see text] can impose tighter constraints on the distance versus redshift relationship. In this paper, we therefore perform an independent test of nine different cosmological models, among which six are expanding, while three are static. Many of these are disfavored by other kinds of observations (including the aforementioned Type Ia SNe). We wish to examine whether the QSO HD confirms or rejects these earlier conclusions. We find that four of these models (Einstein–de Sitter, the Milne universe, the static universe with simple tired light and the static universe with plasma tired light) are excluded at the [Formula: see text] C.L. The quasi-steady state model is excluded at [Formula: see text] C.L. The remaining four models ([Formula: see text]CDM/[Formula: see text]CDM, the [Formula: see text] universe, the Friedmann open universe and a static universe with a linear Hubble law) all pass the test. However, only [Formula: see text]CDM/[Formula: see text]CDM and [Formula: see text] also pass the Alcock–Paczyński (AP) test. The optimized parameters in [Formula: see text]CDM/[Formula: see text]CDM are [Formula: see text] and [Formula: see text] (the dark energy equation-of-state). Combined with the AP test, these values become [Formula: see text] and [Formula: see text]. But whereas this optimization of parameters in [Formula: see text]CDM/[Formula: see text]CDM creates some tension with their concordance values, the [Formula: see text] universe has the advantage of fitting the QSO and AP data without any free parameters.

scholarly journals Transit cosmological models coupled with zero-mass scalar field with high redshift in higher derivative theory

New Astronomy ◽  
2021 ◽  
pp. 101587
Author(s):  
Archana Dixit ◽  
Dinesh Chandra Maurya ◽  
Anirudh Pradhan
Keyword(s):  
Scalar Field ◽  
High Redshift ◽  
Cosmological Models ◽  
Zero Mass ◽  
Higher Derivative

scholarly journals Anisotropic cosmological models in Horndeski gravity

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Rafkat Galeev ◽  
Ruslan Muharlyamov ◽  
Alexei A. Starobinsky ◽  
Sergey V. Sushkov ◽  
Mikhail S. Volkov
Keyword(s):  
Cosmological Models ◽  
Anisotropic Cosmological Models

Cosmic acceleration and stability of cosmological models in extended teleparallel gravity

Pramana ◽  
2021 ◽  
Vol 95 (1) ◽  
Author(s):  
A Y Shaikh ◽  
S V Gore ◽  
S D Katore
Keyword(s):  
Teleparallel Gravity ◽  
Cosmological Models ◽  
Cosmic Acceleration
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