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Hubble expansion in warped braneworld model is addressed in presence of more than one warped extra dimensions. It is shown that while the expansion depends on all the moduli, an exponential nature of the expansion of the scale factor…

High Energy Physics - Theory · Physics 2011-06-10 Narayan Banerjee , Sayantani Lahiri , Soumitra SenGupta

Stars form in the densest regions of molecular clouds, however, there is no universal understanding of the factors that regulate cloud dynamics and their influence on the gas-to-stars conversion. This study considers the impact of Galactic…

Astrophysics of Galaxies · Physics 2024-07-01 Raffaele Rani , Jia-Lun Li , Toby J. T. Moore , David J. Eden , Andrew J. Rigby , Geumsook Park , Yueh-Ning Lee

Our motion through the Universe generates a dipole in the temperature anisotropies of the Cosmic Microwave Background (CMB) and also in the angular distribution of sources. If the cosmological principle is valid, these two dipoles are…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Charles Dalang , Camille Bonvin

We study the cosmology of K-mouflage theories at the background level. We show that the effects of the scalar field are suppressed at high matter density in the early Universe and only play a role in the late time Universe where the…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-02 Philippe Brax , Patrick Valageas

Departures of the energy spectrum of the cosmic microwave background (CMB) from a perfect blackbody probe a fundamental property of the universe -- its thermal history. Current upper limits, dating back some 25 years, limit such spectral…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-01 A. Kogut , M. H. Abitbol , J. Chluba , J. Delabrouille , D. Fixsen , J. C. Hill , S. P. Patil , A. Rotti

A string cosmology scenario ("pre-big-bang") postulates that the evolution of the Universe starts from a state of very small curvature and coupling, undergoes a long phase of dilaton-driven kinetic inflation and at some later time joins…

High Energy Physics - Theory · Physics 2016-10-26 Ram Brustein

We investigate recent claims by Secrest et al. of an anomalously large amplitude of the dipole in the distribution of CatWISE-selected quasars on the sky. Two main issues indicate that the systematic uncertainties in the derived…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Arefe Abghari , Emory F. Bunn , Lukas T. Hergt , Boris Li , Douglas Scott , Raelyn M. Sullivan , Dingchen Wei

In string theory, the traditional picture of a Universe that emerges from the inflation of a very small and highly curved space-time patch is a possibility, not a necessity: quite different initial conditions are possible, and not…

High Energy Physics - Theory · Physics 2017-06-01 M. Gasperini , G. Veneziano

We study the large-scale anisotropy of the Universe by measuring the dipole in the angular distribution of a flux-limited, all-sky sample of 1.36 million quasars observed by the Wide-field Infrared Survey Explorer (WISE). This sample is…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-01 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar , Jacques Colin

The unprecedented sky coverage and photometric uniformity of the Two Micron All Sky Survey (2MASS) provides a rich resource for investigating the galaxies populating the local Universe. A full characterization of the large-scale clustering…

Astrophysics · Physics 2009-11-07 Ariyeh H. Maller , Daniel H. McIntosh , Neal Katz , Martin D. Weinberg

We consider different aspects of the problem of cosmological singularity such as the BKL oscillatory approach to the singularity, the new features of the cosmological dynamics in the neighbourhood of the singularity in multidimensional and…

General Relativity and Quantum Cosmology · Physics 2010-12-17 A. Yu. Kamenshchik

The dynamics of the tilted axisymmetric Bianchi IX cosmological models are explored allowing energy flux in the source fluid. The Einstein equations and the continuity equation are presented treating the equation of state $w$ and the tilt…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Peter Sundell , Tomi Koivisto

We discuss a cosmological model where the universe shrinks rather than expands during the radiation and matter dominated periods. Instead, the Planck mass and all particle masses grow exponentially, with the size of atoms shrinking…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-13 C. Wetterich

The cosmological principle posits that the universe is statistically homogeneous and isotropic on large scales, implying all matter shares the same rest frame. This principle suggests that velocity estimates of our motion from various…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Pedro da Silveira Ferreira , Valerio Marra

With the developments of large galaxy surveys or cosmic shear surveys it is now possible to map the dark matter distribution at truly cosmological scales. Detailed examinations of the statistical properties of the dark matter distribution…

Astrophysics · Physics 2007-05-23 Francis Bernardeau

We present a Bayesian analysis of the Quaia sample of 1.3 million quasars as a test of the cosmological principle. This principle postulates that the universe is homogeneous and isotropic on sufficiently large scales, forming the basis of…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-16 Vasudev Mittal , Oliver T. Oayda , Geraint F. Lewis

The scenario that the Universe contracts towards a big crunch and then undergoes a transition to expanding Universe in envisaged in the quantum string cosmology approach. The Wheeler-De Witt equation is solved exactly for an exponential…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Jnanadeva Maharana

In the concordance model of the Universe, the matter distribution - as observed in galaxy number counts or the intensity of line emission (such as the 21cm line of neutral hydrogen) - should have a kinematic dipole due to the Sun's motion…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-19 Roy Maartens , Chris Clarkson , Song Chen

The largest temperature anisotropy in the cosmic microwave background (CMB) is the dipole. The simplest interpretation of the dipole is that it is due to our motion with respect to the rest frame of the CMB. As well as creating the $\ell$=1…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Raelyn M. Sullivan , Douglas Scott

Peculiar velocities encode rich cosmological information, but their transverse components are hard to measure. Here, we present the first observations of a novel effect of transverse velocities: the dipole signatures that they imprint on…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Yan-Chuan Cai , John A. Peacock , Anna de Graaff , Shadab Alam