The scientific project

The University of Granada focuses its scientific interests on:

The magnetic field influence onto the anisotropy sources.
Cold dust in point-like sources.

Magnetic fields and CMB

Primordial magnetic fields may have important effects on the Cosmic Microwave Background (CMB). Apart from their influence on secondary anisotropies, the Last Scattering Surface (LSS) could preserve the imprints of magnetic fields, modifying the anisotropies spectrum as well as the polarization pattern. Therefore, the determination of cosmológical parameters from these spectra should be corrected if magnetic fields actually play a role.
The influence of magnetic fields on the formation of the large scale of the Universe has been studied previously, showing that primordial comoving field strengths in the range 10(**-9)-10(**-8) G could have a non negligible effect. These strengths should affect, in turn, the CMB anisotropy spectrum, contributing to non-Gaussianity of the temperature distribution, thus causing the formation of anisotropic filaments, which would intersect the LSS and produce other measurable effects.
Magnetic fields act on free electrons wihch are coupled to photons through Thomson scattering and to protons through Coulomb interactions. Magnetic fields, CDM, dark energy, photons, electrons, protons and neutrons are the components of our model, which have different amounts of coupling through the different epochs of the Universe.
The evolution of a filament created by a primordial magnetic flux tube will be reproduced through the radiation dominated era, the epoch of DM and radiation energy densities equality, until reaching photon decoupling at Recombination. The statistical evolution of these initial perturbations will in turn be followed in Fourier Space to determine the final anisotropy spectrum. The formation of primordial magnetic structures is another of our objectives.
The anisotropy spectrum to be expected from non random structures, such as the so called "fractal egg-carton" universe, is another topic to be undertaken, for a comparison with universes with random primordial spectra.
There is an interesting possibility of finding Faraday Rotation in the CMB radiation, through the polarization that Planck will measure with unprecedented sensitivity. Preparatory work for interpreting Planck measurements is in progress.

The existence of primordial magnetic fields, the quantitative determination of these or, at least, the setting of an upper limit of their strengths, are all achievements that could be provided by the Planck Mission.

Cold dust

In order to study the microwave background through the analysis of the PLANCK data, all foreground emission will have to be subtracted. This will provide a huge data base of the dust emission in galaxies in the submillimeter and millimeter bands (wavelength range between 350 mu and 1.4mm), a wavelength range that is very difficult to observe from the earth.
The 5 arcmin spatial resolution in this range will achieve to resolve only the most nearby galaxies, whereas the bulge of the objects will appear as point-like sources for PLANCK.
Nevertheless, the 20.000-30.000 objects that are expected to be detected will provide a unique database and, together with the data from the IRAS satellite in the far-infrared regime, will give us the possibility of reconstructing the entire dust spectral energy distribution (SED). Unfortunately, the dust SED is difficult to interpret due to the fact that different parameters, such as the dust temperture, its distribution and its composition, determine its shape.
At the University of Granada, the aim of our work in this field is to improve our understanding of the dust in galaxies in order to obtain a more reliable interpretation of the statistical data that PLANCK will provide.

Our work mainly focusses on the study and comparison of the presently available data which basically are the ground-based observations of the dust emission (from the submillimeter James Clerk Maxwell Telescope and the millimeter 30m telescope of the Instituto de Radioastronmía Milimetrica) and from presently active satellites such as "Spitzer", which observes in the mid-to far-infrared.
The data from the ultraviolet satellite GALEX are also important because this wavelength range is crucial for the dust heating.
Furthermore we are studying the dust via the extinction it produces, e.g. via the Balmer decrement or optical colours. Taken together, the study of all these data sets in individual galaxies or small samples will increase our knowledge about the different aspects of the dust in galaxies.

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