On the sources of the late integrated Sachs-Wolfe effect

In some scenarios, the peculiar gravitational potential of linear and mildly nonlinear structures depends on time and, as a result of this dependence, a late integrated Sachs-Wolfe effect appears. Here, an appropriate formalism is used which allows us to improve on the analysis of the spatial scales and locations of the main cosmological inhomogeneities producing this effect. The study is performed in the framework of the currently preferred flat model with cosmological constant, and it is also developed in an open model for comparisons. Results from this analysis are used to discuss the contribution of Great Attractor-like objects, voids, and other structures to the CMB anisotropy.Comment: 25 pages, 4 figures, accepted for publication in New Astronom

Embedding realistic surveys in simulations through volume remapping

Connecting cosmological simulations to real-world observational programs is often complicated by a mismatch in geometry: while surveys often cover highly irregular cosmological volumes, simulations are customarily performed in a periodic cube. We describe a technique to remap this cube into elongated box-like shapes that are more useful for many applications. The remappings are one-to-one, volume-preserving, keep local structures intact, and involve minimal computational overhead.Comment: 4 pages, 4 figures. Companion material at http://mwhite.berkeley.edu/BoxRemap

Seeable universe and its accelerated expansion: an observational test

From the equivalence principle, one gets the strength of the gravitational effect of a mass $M$ on the metric at position r from it. It is proportional to the dimensionless parameter $\beta^2 = 2GM/rc^2$, which normally is $<< 1$. Here $G$ is the gravitational constant, $M$ the mass of the gravitating body, $r$ the position of the metric from the gravitating body and $c$ the speed of light. The seeable universe is the sphere, with center at the observer, having a size such that it shall contain all light emitted within it. For this to occur one can impose that the gravitational effect on the velocity of light at $r$ is zero for the radial component, and non zero for the tangential one. Light is then trapped. The condition is given by the equality $R_g = 2GM/c^2$, where $R_g$ represents the radius of the {\it seeable} universe. It is the gravitational radius of the mass $M$. The result has been presented elsewhere as the condition for the universe to be treated as a black hole. According to present observations, for the case of our universe taken as flat ($k = 0$), and the equation of state as $p = - \rho c^2$, we prove here from the Einstein's cosmological equations that the universe is expanding in an accelerated way as $t^2$, a constant acceleration as has been observed. This implies that the gravitational radius of the universe (at the event horizon) expands as $t^2$. Taking $c$ as constant, observing the galaxies deep in space this means deep in time as $ct$, linear. Then, far away galaxies from the observer that we see today will disappear in time as they get out of the distance ct that is $< R_g$. The accelerated expanding vacuum will drag them out of sight. This may be a valid test for the present ideas in cosmology. Previous calculations are here halved by our results.Comment: 15 pages, 2 figure

Quantization of the universe as a black hole

It has been shown that black holes can be quantized by using Bohr's idea of quantizing the motion of an electron inside the atom. We apply these ideas to the universe as a whole. This approach reinforces the suggestion that it may be a way to unify gravity with quantum theory.Comment: 7 pages. Accepted for publication in Astrophysics & Space Science in 25th Octuber 201