منابع مشابه
Modified gravity, Dark Energy and MOND
We propose a class of actions for the spacetime metric that introduce corrections to the Einstein-Hilbert Lagrangian depending on the logarithm of some curvature scalars. We show that for some choices of these invariants the models are ghost free and modify Newtonian gravity below a characteristic acceleration scale given by a0 = cμ, where c is the speed of light and μ is a parameter of the mod...
متن کاملDark Baryons and Rotation Curves
The best measured rotation curve for any galaxy is that of the dwarf spiral DDO 154, which extends out to about 20 disk scale lengths. It provides an ideal laboratory for testing the universal density profile prediction from high resolution numerical simulations of hierarchical clustering in cold dark matter-dominated cosmological models. We find that the observed rotation curve cannot be fit e...
متن کاملDark Baryons in Galactic Halos
Primordial nucleosynthesis as well as anisotropies in the cosmic microwave background radiation imply that the total amount of baryons in the Universe largely exceeds the visible contribution, thereby making a strong case for baryonic dark matter. Moreover, certain recent developments lead to a consistent picture of the dark baryon budget in the present-day Universe. Accordingly, dark baryons a...
متن کاملOn the Halo Occupation of Dark Baryons
We introduce a new technique that adopts the halo occupation framework for understanding the origin of QSO absorption-line systems. Our initial study focuses specifically on Mg II absorbers. We construct a model of the gaseous content in which the absorption equivalent width Wr is determined by the the amount of cold gas, in the form of discrete clouds, along a sightline through a halo. The two...
متن کاملUnified origin of baryons and dark matter
We investigate the possibility that both the baryon asymmetry of the universe and the observed cold dark matter density are generated by decays of a heavy scalar field which dominates the universe before nucleosynthesis. Since baryons and cold dark matter have common origin, this mechanism yields a natural explanation of the similarity of the corresponding energy densities. The cosmological mod...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2009
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/200811085