Topic
Cosmology
About: Cosmology is a research topic. Over the lifetime, 18004 publications have been published within this topic receiving 631028 citations. The topic is also known as: physical cosmology & cosmologies.
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TL;DR: In this article, it is shown that the acceleration of the universe can be understood by considering a F(T) gravity model, and a variant of the accelerating cosmology reconstruction program is developed.
Abstract: It is shown that the acceleration of the universe can be understood by considering a F(T) gravity models. For these F(T) gravity models, a variant of the accelerating cosmology reconstruction program is developed. Some explicit examples of F(T) are reconstructed from the background FRW expansion history.
397 citations
TL;DR: In this paper, the authors search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity, and find that models can be made consistent with solar system constraints either by giving the scalar a high mass or by exploiting the so-called chameleon effect.
Abstract: We search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity. We find that models can be made consistent with solar system constraints either by giving the scalar a high mass or by exploiting the so-called chameleon effect. However, in both cases, it appears likely that any late-time cosmic acceleration will be observationally indistinguishable from acceleration caused by a cosmological constant. We also explore further observational constraints from, e.g., big bang nucleosynthesis and inflation.
396 citations
TL;DR: In this paper, the authors present a comprehensive overview of galaxy bias, that is, the statistical relation between the distribution of galaxies and matter, which forms the basis of the rigorous perturbative description of galaxy clustering, under the assumptions of General Relativity and Gaussian, adiabatic initial conditions.
394 citations
TL;DR: In this article, it is suggested that current cosmic acceleration arises due to modification of general relativity by the terms with negative powers of curvature, and that such a model which seems to eliminate the need for dark energy may have the origin in M-theory.
388 citations
TL;DR: In this paper, the authors used cosmological simulations that incorporate a physically motivated approximation to three dimensional radiative transfer that recovers correct asymptotic ionization front propagation speeds for some cosmologically relevant density distributions to investigate the process of the reionization of the universe by ionizing radiation from protogalaxies.
Abstract: I use cosmological simulations that incorporate a physically motivated approximation to three- dimensional radiative transfer that recovers correct asymptotic ionization front propagation speeds for some cosmologically relevant density distributions to investigate the process of the reionization of the universe by ionizing radiation from protogalaxies. Reionization proceeds in three stages and occupies a large redshift range from z D 15 until z D 5. During the —rst, ii preoverlap ˇˇ stage, H II regions gradually expand into the low-density intergalactic medium, leaving behind neutral high-density protrusions. During the second, ii overlap ˇˇ stage, that occurs in about 10% of the Hubble time, H II regions merge and the ionizing background rises by a large factor. During the third, ii postoverlap ˇˇ stage, remaining high-density regions are being gradually ionized as the required ionizing photons are being produced. Residual —uctuations in the ionizing background reach signi—cant (more than 10%) levels for the Lya forest absorption systems with column densities above 1014¨1015 cm~2 at z \ 3¨4. Subject headings: cosmology: theorygalaxies: formationintergalactic medium ¨ large-scale structure of universe
388 citations