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With considerations of the recently released WMAP year three and supernova legacy survey (SNLS) data set analysis that favors models similar to the $% \Lambda CDM$ model by possibly mild fluctuations around the vacuum energy or the…

天体物理学 · 物理学 2007-05-23 Xin He Meng , Ming Guang Hu , Jie Ren

Future sattelite, balloon and ground based experiments will give precision determinations of the basic cosmological parameters and hence determine the amount of cold dark matter accurately. We consider here two cosmological models, the…

高能物理 - 唯象学 · 物理学 2008-11-26 Pran Nath , R. Arnowitt

The status of the standard cosmological model, also known as "LCDM" is described. With some simple assumptions, this model fits a wide range of data, with just six (or seven) free parameters. One should be skeptical about this claim, since…

宇宙学与河外天体物理 · 物理学 2018-04-05 Douglas Scott

We constrain and compare the $w_{0}w_{a}$CDM dynamical dark energy model and three $f(R)$ modified gravity models using the current cosmological distance measurements, including 112 high-quality localized FRBs, BAO measurements from the…

宇宙学与河外天体物理 · 物理学 2026-02-24 Shuai Feng , Yan Gong , Xiaohui Liu , Jun-Hui Yan , Xuelei Chen

In the late 1990's, observations of 93 Type Ia supernovae were analysed in the framework of the FLRW cosmology assuming these to be `standard(isable) candles'. It was thus inferred that the Hubble expansion rate is accelerating as if driven…

宇宙学与河外天体物理 · 物理学 2021-09-13 Roya Mohayaee , Mohamed Rameez , Subir Sarkar

The kinematic approach to cosmological tests provides a direct evidence to the present accelerating stage of the universe which does not depend on the validity of general relativity, as well as on the matter-energy content of the Universe.…

天体物理学 · 物理学 2009-03-12 J. V. Cunha

The recently discovered high redshift galaxy, 53W091, with accurate age measurements (Dunlop et al 1996) provides a measure of the small-scale power of the primordial density field and, as we show, a crucial test of the inflation-inspired…

天体物理学 · 物理学 2007-05-23 A. Kashlinsky , R. Jimenez

In this paper, the Dvali-Gabadadze-Porrati (DGP) brane model is confronted by current cosmic observational data sets from geometrical and dynamical perspectives. On the geometrical side, the recent released Union2 $557$ of type Ia…

宇宙学与河外天体物理 · 物理学 2014-11-21 Lixin Xu , Yuting Wang

In this article, we study the expanding nature of universe in the contest of $f(R,L_m)$ gravity theory, here $ R $ represents the Ricci scalar and $ L_m $ is the matter Lagrangian density. With a specific form of $ f(R,L_m) $, we obtain the…

广义相对论与量子宇宙学 · 物理学 2023-06-28 J. K. Singh , Shaily , Ratbay Myrzakulov , Harshna Balhara

Cosmologies including continuous matter creation are able to reproduce the main properties of the standard $\Lambda$CDM model, in particular in cases where the particle and entropy production rates are equal. These specific models,…

广义相对论与量子宇宙学 · 物理学 2011-03-07 Alain de Roany , J. A. de Freitas Pacheco

We consider the hypothesis of a limiting minimal curvature in gravity as a way to construct a class of theories exhibiting late-time cosmic acceleration. Guided by the minimal curvature conjecture (MCC) we are naturally lead to a set of…

天体物理学 · 物理学 2010-10-27 Damien A. Easson

We study the effect of a phenomenological parameterized quintessence model on low, intermediate and high redshift observations. At low and intermediate redshifts, we use the Gold sample of supernova Type Ia (SNIa) data and recently observed…

天体物理学 · 物理学 2009-11-13 M. Sadegh Movahed , Sohrab Rahvar

We investigate a phenomenological extension of the standard $\Lambda$CDM framework, the $\Omega_1\Omega_2$-$\Lambda$CDM model, in which the total energy density of the universe is expanded in powers of $1+z$. This parameterization recovers…

宇宙学与河外天体物理 · 物理学 2026-02-20 Suresh Kumar

In cosmology many dramatically different scenarios with the past (big bang versus bounce) and in the future (de Sitter versus big rip) singularities are compatible with the present day observations. This difficulty is called the degeneracy…

天体物理学 · 物理学 2009-11-13 Wlodzimierz Godlowski Marek Szydlowski

We present a convolutional neural network to classify distinct cosmological scenarios based on the statistically similar weak-lensing maps they generate. Modified gravity (MG) models that include massive neutrinos can mimic the standard…

宇宙学与河外天体物理 · 物理学 2019-07-17 Austin Peel , Florian Lalande , Jean-Luc Starck , Valeria Pettorino , Julian Merten , Carlo Giocoli , Massimo Meneghetti , Marco Baldi

The new 182 gold supernova Ia data, the baryon acoustic oscillation measurement and the shift parameter determined from the Sloan Digital Sky Survey and the three-year Wilkinson Microwave Anisotropy Probe data are combined to reconstruct…

天体物理学 · 物理学 2008-11-26 Yungui Gong , Anzhong Wang

In this work, we consider three different $f(Q)$ models, such as power-law, exponential, and logarithmic, to study which model better mimics $\Lambda$CDM evolution theoretically. Henceforth, we determine solutions to the $f(Q)$ gravity…

广义相对论与量子宇宙学 · 物理学 2024-05-10 Gaurav N. Gadbail , P. K. Sahoo

An alternative to the postulate of dark energy required to explain the accelerated expansion of the universe is to adopt an inhomogeneous cosmological model to explain the supernovae data without dark energy. We adopt a void cosmology…

宇宙学与河外天体物理 · 物理学 2016-08-02 J. W. Moffat

The DGP brane-world model provides an alternative to the standard LCDM cosmology, in which the late universe accelerates due to a modification of gravity rather than vacuum energy. The cosmological constant $\Lambda$ in LCDM is replaced by…

天体物理学 · 物理学 2009-11-13 Kazuya Koyama , Roy Maartens

We re-examine the contentious question of constraints on anisotropic expansion from Type Ia supernovae (SNIa) in the light of a novel determination of peculiar velocities, which are crucial to test isotropy with supernovae out to distances…

宇宙学与河外天体物理 · 物理学 2022-06-08 W. Rahman , R. Trotta , S. S. Boruah , M. J. Hudson , D. A. van Dyk
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