Dark energy in motion
نویسنده
چکیده
Recent large-scale peculiar velocity surveys suggest that large matter volumes could be moving with appreciable velocity with respect to the CMB rest frame. If confirmed, such results could conflict with the Cosmological Principle according to which the matter and CMB rest frames should converge on very large scales. In this work we explore the possibility that such large scale bulk flows are due, not to the motion of matter with respect to the CMB, but to the flow of dark energy with respect to matter. Indeed, when dark energy is moving, the usual definition of the CMB rest frame as that in which the CMB dipole vanishes is not appropriate. We find instead that the dipole vanishes for observers at rest with respect to the cosmic center of mass, i.e. in motion with respect to the background radiation. ∗ Essay selected for “Honorable Mention” in the 2006 Awards for Essays on Gravitation (Gravity Research Foundation)
منابع مشابه
Formation of Large Structures in the Acceleration Universe with a Hybrid Expansion Law
In the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. For this purpose, we used both WMAP9 and Planck data to study how the radius changes with redshift in these mod-els. We used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. The mechanism of structure formation f...
متن کاملگذار از مرز فانتوم با جفتیدگی ناکمینه جنبشی و گاؤس- بانه
In this paper we study a dark energy model in which tachyon scalar field non-minimally coupled with kinetic energy and Gauss-Bonnet invariant. Energy density рø, pressure рø and scalar field equation of motion have been calculated and then equation of state parameter has been extracted. We have investigated the conditions required for ω=-1 crossing in such a model. It is shown that phantom divi...
متن کاملMoving dark energy and the CMB dipole
We explore the possibility that the rest frames of CMB, matter and dark energy differ one from another, i.e. they do not converge on very large scales. In such a case, the usual interpretation of the CMB dipole as being due to the relative motion of the observer with respect to the CMB rest frame is not appropriate. Instead, we find that the measured dipole is due to the observer motion relativ...
متن کاملDark energy rest frame and the CMB dipole
If dark energy can be described as a perfect fluid, then, apart from its equation of state relating energy density and pressure, we should also especify the corresponding rest frame. Since dark energy is typically decoupled from the rest of components of the universe, in principle such a frame could be different from that of matter and radiation. In this work we consider the potential observabl...
متن کاملDensity Evolution in the New Modified Chaplygin Gas Model
In this paper, we have considered new modified Chaplygin gas (NMCG) model which interpolates between radiation at early stage and ΛCDM at late stage. This model is regarded as a unification of dark energy and dark matter (with general form of matter). We have derived the density parameters from the equation of motion for the interaction between dark energy and dark matter. Also we have studied ...
متن کاملCosmology with Interaction between Phantom Dark Energy and Dark Matter and the Coincidence Problem
We study a cosmological model in which phantom dark energy has an interaction with dark matter by introducing a term in the equations of motion of dark energy and dark matter. Such a term is parameterized by a product of a dimensionless coupling function δ, Hubble parameter and the energy density of dark matter, and it manifests an energy flow between the dark energy and dark matter. We discuss...
متن کامل