Conveners
Tuesday afternoon
- Jose Alberto Ruiz Cembranos (UCM)
The Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have provided a strong confirmation of the LCDM model of structure formation. However, there are a few interesting tensions with other cosmological probes that leave the door open to possible extensions to LCDM. I will review some extended cosmological scenarios, in order to find...
In this work, we explore the possibility of topological defects as viable dark matter candidates. The non-thermal production of magnetic monopoles by a phase transition is studied. The Kibble mechanism is analyzed, concluding that it is not a good approach to estimate their abundance and studying the corrections of the Kibble-Zurek model. We also study the effect of monopoles annihilation...
In flat spacetime, an instability problem arises in the homogeneous field configuration of a system with concave potential. We extend that analysis to an accelerated expanding universe where the potential is not needed to be concave in order to have instabilities. We study the particular case of an inflationary universe with a slow-roll phase and calculate the lifetime associated to its decay....
In warm inflation, substantial radiation production can occur concurrently with the inflationary expansion. In the strong dissipative regime, the temperature dependent dissipative coefficient leads to the wrong spectral index. An imperfect radiation fluid, via shear effects, can successfully solve that problem, although one needs to resort to weakly interacting fluids. However, certain...
In this talk I will present a new modified theory of gravitation, that includes infinite derivatives and torsion in the action. I shall also provide some solutions that are ghost and singularity free.
In this talk we shall consider the possibility of chiral symmetry restoration for observers located close to acceleration horizons, black holes and cosmological horizons. The Thermalization Theorem formalism and the large N limit (with N being the number of pions) will be employed to solve the lowest-order approximation to QCD at low energies in Rindler spacetime and close to the horizons of...
Although the Lambda cold dark matter model (ΛCDM) has become the best phenomenological description for the late-time accelerating phase of the Universe, the yet unsolved cosmological constant problem has driven an effort towards alternatives. We will mention two leading approaches which avoid the introduction of a cosmological constant. On the one hand, Dark Energy (DE) models where yet...
I will briefly outline the first progresses with miniJPAS, the JPAS-like data obtained with the Pathfinder camera attached to the JST/T250 telescope at the OAJ. This small data set already encodes all the richness and complexity to be expected for regular J-PAS data, and allows defining the hottest science cases to be addressed with the main survey. I will also describe the strategy for J-PAS...
The next generation of galaxy surveys will allow us to test one of the most fundamental assumptions of the standard cosmology, i.e., that gravity is governed by the general theory of relativity (GR). In this paper we investigate the ability of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) to constrain GR and its extensions. Based on the J-PAS information on...
We compare the statistics and morphology of arcs in galaxy clusters using simulations with standard cold dark matter and simulations where dark matter has a probability of interaction (parametrized by its cross section), i.e self-interacting dark matter. Through ray tracing, we produce a statistically large number of arcs around galaxy clusters at different redshifts. Since dark matter in more...
Dark matter, as a cold collisionless fuid, effectively occupies a three-dimensional sub-manifold in six-dimensional phase space. In simulations, this "dark matter sheet" can in principle be reconstructed by interpolation techniques to obtain an almost exact density estimate. However, in regions of strong mixing (like dark matter haloes), this is difficult due to the rapid growth of the sheet's...
We study the dependence of a variety of halo properties (shape, spin, virialisation status) on different environments in a whole-sky ΛCDM light-cone halo catalogue extending to z ∼ 0.65,CDM light-cone halo catalogue extending to z ∼ 0.65, 0.65, using a simple and well-defined halo isolation criterion. Using this definition of the environment we study if and how the DM halo-properties and their...
If dark matter particles annihilate, then we should detect signals of this annihilation in the sky. In this talk we will focus on the contribution of particle dark matter in the injection of cosmic rays in dwarf spheroidals and the synchrotron emission from secondary processes. We also study the Square Kilometre Array (SKA) sensitivity in the detection of dark matter candidates that would fit...
I employ methods of fractal geometry and fluid turbulence to describe how the cosmic web structure arises in the nonlinear regime of evolution of the LCDM cosmology. I evaluate this theory with the results of N-body simulations and observations of the galaxy distribution by the Sloan Digital Sky Survey.
