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相关论文: Isotropy of low redshift type Ia Supernovae: A Bay…

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The assumption of homogeneity and isotropy on large scales is one of the main hypotheses of the standard cosmological model. In this paper, we revisit a test of cosmological isotropy using type Ia supernova (SN Ia) distances provided by the…

宇宙学与河外天体物理 · 物理学 2018-10-01 Uendert Andrade , Carlos A. P. Bengaly , Beethoven Santos , Jailson S. Alcaniz

We investigate the validity of the Cosmological Principle by mapping the cosmological parameters $H_0$ and $q_0$ through the celestial sphere. In our analysis, performed in a low-redshift regime to follow a model-independent approach, we…

宇宙学与河外天体物理 · 物理学 2015-07-21 C. A. P. Bengaly , A. Bernui , J. S. Alcaniz

We investigate the validity of the Cosmological Principle by constraining the cosmological parameters $H_0$ and $q_0$ through the celestial sphere. Our analyses are performed in a low-redshift regime in order to follow a model independent…

宇宙学与河外天体物理 · 物理学 2016-02-04 C. A. P. Bengaly, , A. Bernui , J. S. Alcaniz

We probe the possible anisotropy of the Universe by using the JLA compilation of type-Ia supernovae. We apply the Markov Chain Monte Carlo (MCMC) method to constrain the amplitude and direction of anisotropy in three cosmological models.…

宇宙学与河外天体物理 · 物理学 2016-01-29 Hai-Nan Lin , Sai Wang , Zhe Chang , Xin Li

We analyze the magnitude-redshift data of type Ia supernovae included in the Union and Union2 compilations in the framework of an anisotropic Bianchi type I cosmological model and in the presence of a dark energy fluid with anisotropic…

宇宙学与河外天体物理 · 物理学 2011-05-12 L. Campanelli , P. Cea , G. L. Fogli , A. Marrone

The cosmological principle is one of the cornerstones in modern cosmology. It assumes that the universe is homogeneous and isotropic on cosmic scales. Both the homogeneity and the isotropy of the universe should be tested carefully. In the…

宇宙学与河外天体物理 · 物理学 2018-06-19 Hua-Kai Deng , Hao Wei

We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique…

宇宙学与河外天体物理 · 物理学 2015-08-31 Behnam Javanmardi , Cristiano Porciani , Pavel Kroupa , Jan Pflamm-Altenburg

We test the cosmological principle by fitting a dipolar modulation of distance modulus and searching for an evolution of this modulation with respect to cosmological redshift. Based on a redshift tomographic method, we divide the Joint…

宇宙学与河外天体物理 · 物理学 2018-07-06 Zhe Chang , Hai-Nan Lin , Yu Sang , Sai Wang

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

In this paper, we study an anisotropic universe model with Bianchi-I metric using Joint Light-curve Analysis (JLA) sample of type Ia supernovae (SNe Ia). Because light-curve parameters of SNe Ia vary with different cosmological models and…

宇宙学与河外天体物理 · 物理学 2017-12-27 Y. Y. Wang , F. Y. Wang

Recent studies have indicated that an anisotropic cosmic expansion may exist. In this paper, we use three datasets of type Ia supernovae (SNe Ia) to probe the isotropy of cosmic acceleration. For the Union2.1 dataset, the direction and…

宇宙学与河外天体物理 · 物理学 2019-10-23 Z. Q. Sun , F. Y. Wang

The cosmological principle assumes the isotropy of the Universe at large scales. It is a foundational assumption in the $\Lambda$CDM model, which is the current standard model of cosmology. Recent tensions give legitimacy to investigating…

The cosmological principle asserts that the Universe looks spatially homogeneous and isotropic on sufficiently large scales. Given the fundamental implications of the cosmological principle, it is important to empirically test its validity…

宇宙学与河外天体物理 · 物理学 2023-01-11 Suhail Dhawan , Antonin Borderies , Hayley J. Macpherson , Asta Heinesen

In this paper, we study the anisotropy of cosmic acceleration the using Pantheon sample, which includes 1048 spectroscopically confirmed Type Ia supernovae (SNe Ia) covering the redshift range $0.01 < z < 2.3$. In hemisphere comparison…

宇宙学与河外天体物理 · 物理学 2018-07-05 Z. Q. Sun , F. Y. Wang

The cosmological principle assumes that the universe is homogeneous and isotropic on cosmic scales. There exist many works testing the cosmic homogeneity and/or the cosmic isotropy of the universe in the literature. In fact, some…

宇宙学与河外天体物理 · 物理学 2018-09-21 Hua-Kai Deng , Hao Wei

The question of the transition to global isotropy from our anisotropic local Universe is studied using the Union 2 catalogue of Type Ia supernovae (SNe Ia). We construct a "residual" statistic sensitive to systematic shifts in their…

宇宙学与河外天体物理 · 物理学 2015-03-17 Jacques Colin , Roya Mohayaee , Subir Sarkar , Arman Shafieloo

The cosmological principle, as the cornerstone of the standard cosmological model, requires that the Universe be homogeneous and isotropic on large scales. As a fundamental assumption, it is constantly subjected to testing via various…

宇宙学与河外天体物理 · 物理学 2026-04-21 Jianping Hu , Chao Geng , Xuandong Jia , Zhaoyu Zuo , Taozhi Yang , Fayin Wang

We examine three SNe Type Ia datasets: Union2.1, JLA and Panstarrs to check their consistency using cosmology blind statistical analyses as well as cosmological parameter fitting. We find that Panstarrs dataset is the most stable of the…

宇宙学与河外天体物理 · 物理学 2017-06-28 Ujjaini Alam , Jeremie Lasue

Observations reveal a `bulk flow' in the local Universe which is faster and extends to much larger scales than is expected around a typical observer in the standard $\Lambda$CDM cosmology. This is expected to result in a scale-dependent…

宇宙学与河外天体物理 · 物理学 2019-11-27 Jacques Colin , Roya Mohayaee , Mohamed Rameez , Subir Sarkar

We investigate the possible anisotropy of the universe using the most up-to-date type Ia supernovae, i.e. the Pantheon+ compilation. We fit the full Pantheon+ data with the dipole-modulated $\Lambda$CDM model, and find that it is well…

宇宙学与河外天体物理 · 物理学 2023-10-26 Li Tang , Hai-Nan Lin , Liang Liu , Xin Li
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