Constraining dark energy interacting models with WMAP

We determine the range of parameter space of an interacting quintessence (IQ) model that best fits the luminosity distance of type Ia supernovae data and the recent WMAP measurements of Cosmic Microwave Background temperature anisotropies. Models in which quintessence decays into dark matter provide a clean explanation for the coincidence problem. We focus on cosmological models of zero spatial curvature. We show that if the dark energy (DE) decays into cold dark matter (CDM) at a rate that brings the ratio of matter to dark energy constant at late times, the supernovae data are not sufficient to constrain the interaction parameter. On the contrary, WMAP data constrain it to be smaller than $c^2 < 10^{-2}$ at the $3\sigma$ level. Accurate measurements of the Hubble constant and the dark energy density, independent of the CMB data, would support/disprove this set of models.Comment: 4 pages, 3 figures. Uses AIP style. To be published in the AIP Proceedings of the XXVIII Spanish Relativity Meetin

Is there Any Evidence for Integrated Sachs-Wolfe Signal in WMAP First Year Data?

We introduce a pixel-to-pixel comparison method to detect the temperature anisotropies on the Cosmic Microwave Background induced by the time variation of gravitational potentials along the line of sight. We demonstrate it to be more sensitive than the cross-correlation method used in previous studies. We compare the recent WMAP data with templates constructed from galaxy catalogues. A positive cross-correlation between both data sets will be a signature of an accelerated expansion of the Universe. Contrary to other authors, we fail to detect any signal, except those coming from foreground residuals. Either the effect of an accelerated expansion is not present on the WMAP data or the galaxy catalogues at present do not trace the evolution of the large scale gravitational field

Serie de Conferencias: “Temas actuales de Física”

Memoria ID-350. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2013-2014.[ES] La presente memoria describe las actuaciones llevadas a cabo durante el curso 2013/2014 en las asignaturas de: Laboratorio de Física de primer curso y Mecánica I de segundo curso, ambas del Grado en Física. Asimismo se han aplicado e las actuaciones llevadas a cabo en ste proyecto a la asignatura deResolución de Ecuaciones de la Física en el Master de Física de la Universidad de Salamanca. Las actividades de este proyecto de innovación docente fueron proyectadas y ejecutadas para unos 150 alumnos matriculados en total en estas asignaturas . Adicionalmente, el resto de alumnos del Grado y Master de Física, así como profesores, fueron invitados a participar en todas las actividades. EL grupo innovador estuvo integrado por el profesor CU, el Dr. Fernando Atrio Barandela y la profesora PCD, la Dra. M. Ángeles Pérez García que ha sido coordinadora. Los dos han venido elaborando de forma continuada innovación docente, mayoritariamente dentro de las convocatorias de la USAL de Programas de Innovación y Mejoras docentes. Pasamos a detallar en la siguiente memoria las actuaciones realizadas, los resultados, su análisis y las conclusiones

Dynamics of Interacting Quintessence Models: Observational Constraints

Interacting quintessence models have been proposed to explain or, at least, alleviate the coincidence problem of late cosmic acceleration. In this paper we are concerned with two aspects of these kind of models: (i) the dynamical evolution of the model of Chimento et al. [L.P. Chimento, A.S. Jakubi, D. Pavon, and W. Zimdahl, Phys. Rev. D 67, 083513 (2003).], i.e., whether its cosmological evolution gives rise to a right sequence of radiation, dark matter and dark energy dominated eras, and (ii) whether the dark matter dark energy ratio asymptotically evolves towards a non-zero constant. After showing that the model correctly reproduces these eras, we correlate three data sets that constrain the interaction at three redshift epochs: $z\le 10^{4}$, $z=10^{3}$, and $z=1$. We discuss the model selection and argue that even if the model under consideration fulfills both requirements, it is heavily constrained by observation. The prospects that the coincidence problem can be explained by the coupling of dark matter to dark energy are not clearly favored by the data.Comment: 16 pages, 7 figures and 3 tables. Modifications introduced to match published versio