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We have reanalysed constraints on the equation of state parameter, w_Q = P/rho, of the dark energy, using several cosmological data sets and relaxing the usual constraint w_Q > -1. We find that combining Cosmic Microwave Background, large…

Astrophysics · Physics 2009-11-07 Steen Hannestad , Edvard Mortsell

We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were…

A hierarchical Bayesian method is applied to the analysis of Type-Ia supernovae (SNIa) observations to constrain the properties of the dark matter haloes of galaxies along the SNIa lines-of-sight via their gravitational lensing effect. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 N. V. Karpenka , M. C. March , F. Feroz , M. P. Hobson

Testing the equality of the covariance matrices of two high-dimensional samples is a fundamental inference problem in statistics. Several tests have been proposed but they are either too liberal or too conservative when the required…

Statistics Theory · Mathematics 2023-01-04 Jin-Ting Zhang , Jingyi Wang , Tianming Zhu

Owing to the mass-sheet degeneracy, cosmic shear maps do not probe directly the Fourier modes of the underlying mass distribution on scales comparable to the survey size and larger. To assess the corresponding effect on attainable…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Julien Carron , István Szapudi

We study supernova (SN) classification using the machine learning method of the Recurrent Neural Network (RNN) in the Chinese Space Station Survey Telescope Ultra-Deep Field (CSST-UDF) photometric survey, and explore the improvement of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-05 Minglin Wang , Yan Gong , Dejia Zhou , Xuelei Chen

Quintessence has been introduced as an alternative to the cosmological constant scenario to account for the current acceleration of the universe. This new dark energy component allows values of the equation of state parameter…

Astrophysics · Physics 2009-11-06 P. S. Corasaniti , E. J. Copeland

Type Ia supernovae (SNIe) are generally accepted to act as standardisable candles, and their use in cosmology led to the first confirmation of the as yet unexplained accelerated cosmic expansion. Many of the theoretical models to explain…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-31 Bill S. Wright , Baojiu Li

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…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-04 C. A. P. Bengaly, , A. Bernui , J. S. Alcaniz

Dark energy and the accelerated expansion of the universe have been the direct predictions of the distant supernovae Ia observations which are also supported, indirectly, by the observations of the CMB anisotropies, gravitational lensing…

Astrophysics · Physics 2008-11-26 Ram Gopal Vishwakarma

Type Ia supernovae (SNe Ia) are a prime tool in observational cosmology. A relation between their peak luminosities and the shapes of their light curves allows to infer their intrinsic luminosities and to use them as distance indicators.…

Solar and Stellar Astrophysics · Physics 2010-02-15 F. K. Roepke , W. Hillebrandt , D. Kasen , S. E. Woosley

We perform a cosmographic analysis using several cosmological observables such as the luminosity distance moduli, the volume distance, the angular diameter distance and the Hubble parameter. These quantities are determined using different…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Jun-Qing Xia , Vincenzo Vitagliano , Stefano Liberati , Matteo Viel

We probe the systematic uncertainties from 113 Type Ia supernovae (SNIa) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. (2013) describes the photometric…

We present the results of a novel new search of the first data-release from the Sloan Digital Sky Survey (SDSS-DR1) for the spectra of supernovae. The use of large spectroscopic galaxy surveys offers the prospect of obtaining improved…

Astrophysics · Physics 2009-11-10 Darren S. Madgwick , Paul Hewett , Daniel Mortlock , Lifan Wang

In this work, a computer optimization model has been developed that allows one to load the initial observation data of supernovae 1a into a table and, simply, by searching for the best fit between observations and theory, obtain the values…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-02 A. P. Mahtessian , G. S. Karapetian , M. A. Hovhannisyan , L. A. Mahtessian

Type Ia supernovae (SNe Ia) are one of the major tools to determine the cosmological parameters. Utilizing them as distance indicators, it is possible to geometrically survey the universe. To this end, the intrinsic scatter in the…

Astrophysics · Physics 2007-05-23 F. K. Roepke , W. Hillebrandt , S. I. Blinnikov

We use multi-band imagery data from the Sloan Digital Sky Survey (SDSS) to measure projected distances of 302 supernova type Ia (SNIa) from the centre of their host galaxies, normalized to the galaxy's brightness scale length, with a…

Astrophysics of Galaxies · Physics 2019-01-02 R. Hill , H. Shariff , R. Trotta , S. Ali-Khan , X. Jiao , Y. Liu , S. K. Moon , W. Parker , M. Paulus , D. A. van Dyk , L. B. Lucy

We test the distance--duality relation $\eta \equiv d_L / [ (1 + z)^2 d_A ] = 1$ between cosmological luminosity distance ($d_L$) from the JLA SNe Ia compilation (arXiv:1401.4064) and angular-diameter distance ($d_A$) based on Baryon…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-16 Cong Ma , Pier-Stefano Corasaniti

Type Ia supernova (SNIa) are excellent probes of local distance, and the increasing sample sizes of SNIa have driven an increased need to study the associated systematic uncertainties and improve the standardisation methods in preparation…

We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization $w(a)=w_0+w_1…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 J. C. Bueno Sanchez , S. Nesseris , L. Perivolaropoulos
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