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Measurements suggest that our universe has a substantial dark energy component. The most recent data on type Ia supernovae give a dark energy density which is in good agreement with other measurements if the dark energy is assumed to be a…

Astrophysics · Physics 2009-11-10 Duane A. Dicus , Wayne W. Repko

We show that the cosmic microwave background (CMB) data of WMAP can give subelectronvolt limit on the neutrino mass: m_nu < 0.63 eV (95% CL). We also investigate its degeneracy with other cosmological parameters. In particular, we show the…

Astrophysics · Physics 2008-11-26 Kazuhide Ichikawa

Although well motivated from theoretical arguments, the cosmological constant \emph{barrier}, i.e., the imposition that the equation-of-state parameter of dark energy ($\omega_x \equiv p_x/\rho_x$) is $\geq -1$, seems to introduce bias in…

Astrophysics · Physics 2009-11-10 J. S. Alcaniz

We investigate whether cosmological data suggest the need for massive neutrinos. We employ galaxy power spectrum measurements from the Sloan Digital Sky Survey (SDSS) and the Two Degree Field Galaxy Redshift Survey (2dFGRS), along with…

High Energy Physics - Phenomenology · Physics 2008-11-26 V. Barger , Danny Marfatia , Adam Tregre

We perform fits to DESI, CMB and supernova data to understand the physical origin of the DESI hint for dynamical dark energy. We find that the linear parametrization of the equation of state $w$ may guide to misleading interpretations, such…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-27 Ioannis D. Gialamas , Gert Hütsi , Kristjan Kannike , Antonio Racioppi , Martti Raidal , Martin Vasar , Hardi Veermäe

We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8, from peculiar velocities, CMB and type Ia supernovae. These three data sets directly probe the mass in the Universe, without the need to…

Astrophysics · Physics 2009-10-31 S. L. Bridle , I. Zehavi , A. Dekel , O. Lahav , M. P. Hobson , A. N. Lasenby

We present constraints on the parameters of the $\Lambda$CDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly$\alpha$ forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey…

The suggestion that we occupy a privileged position near the centre of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-11 Adam Moss , James P. Zibin , Douglas Scott

We study the cosmological constraints of the time variation of the electron mass $m_e$ and the fine-structure constant $\alpha$, using data of cosmic microwave background, supernovae light curve and baryon acoustic oscillation (BAO) data…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-15 Yo Toda , Osamu Seto

The recent release of high-precision cosmological data, particularly the small-scale cosmic microwave background (CMB) measurements from ACT and baryon acoustic oscillation (BAO) data from DESI, has opened a new landscape for probing the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-06 Lu Feng , Tian-Nuo Li , Guo-Hong Du , Jing-Fei Zhang , Xin Zhang

High-precision data from observation of the cosmic microwave background and the large scale structure of the universe provide very tight constraints on the effective parameters that describe cosmological inflation. Indeed, within a…

Astrophysics · Physics 2008-11-26 Jan Hamann , Steen Hannestad , Martin S. Sloth , Yvonne Y. Y. Wong

We extend our previous analysis of cosmological supernova data (Padmanabhan & Choudhury 2003) to include three recent compilation of data sets. Our analysis ignores systematic effects in the data and concentrates on some key theoretical…

Astrophysics · Physics 2009-11-10 T. Roy Choudhury , T. Padmanabhan

We consider the inference of the cosmic radiation density, traditionally parameterised as the effective number of neutrino species N_eff, from precision cosmological data. Paying particular attention to systematic effects, notably…

Astrophysics · Physics 2008-11-26 Jan Hamann , Steen Hannestad , Georg G. Raffelt , Yvonne Y. Y. Wong

Considering the mass splittings of three active neutrinos, we investigate how the nature of dark energy affects the cosmological constraints on the total neutrino mass $\sum m_\nu$ using the latest cosmological observations. In this paper,…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Ming Zhang , Jing-Fei Zhang , Xin Zhang

A significant lower limit on the mass of the lightest neutralino \chi can be obtained by combining the results from sparticle searches at LEP at centre-of-mass energies up to 172 GeV with cosmological considerations, if it is assumed that…

High Energy Physics - Phenomenology · Physics 2009-09-11 John Ellis , Toby Falk , Keith A. Olive , Michael Schmitt

The accelerating expansion of the universe is the most surprising cosmological discovery in many decades. In this short review, we briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-03 Michael J. Mortonson , David H. Weinberg , Martin White

The possibility of determining cosmological parameters on the basis of a wide set of observational data including the Abell-ACO cluster power spectrum and mass function, peculiar velocities of galaxies, the distribution of Ly-$\alpha$…

Astrophysics · Physics 2007-05-23 B. Novosyadlyj , R. Durrer , S. Gottloeber , V. N. Lukash , S. Apunevych

A number of recent works in astronomy and cosmology have relied upon theoretical He I emissivities, but we know of no effort to quantify the uncertainties in the atomic data. We analyze and assign uncertainties to all relevant atomic data,…

Astrophysics · Physics 2009-11-13 R. L. Porter , G. J. Ferland , K. B. MacAdam , P. J. Storey

The discussion of cosmological parameters used to be a source of embarrassment to cosmologists. Today, measurements of the cosmological parameters are leading the way into the era of precision cosmology. The CMB temperature is measured to…

Astrophysics · Physics 2009-10-31 Michael S. Turner