Research sublines
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Many open questions remain concerning Active Galactic Nuclei (AGNs). The mechanism responsible for triggering the non-thermal nuclear activity (mergers/interactions or secular evolution of the host galaxies?), the conditions required to switch on the nuclear activity and how the properties of the host galaxy relate to the different levels of activity are not known. Both the origin of the gas accreted onto the black hole and how it loses its angular momentum before being accreted need to be elucidated. To investigate all these questions, a quantification of the relationship between AGN class (LINER, Seyfert 1 or 2), the morphological type of the host galaxy and the environment, needs to be determined. Another open question concerns the relationship between Seyfert and LINER activity, to know whether they are a result of scaling of the AGN energetics or they are connected to the galaxy evolution and the accreting mechanism onto the black hole. As a result from this project we expect to provide some hints on the unification of AGNs.
On the other hand, AGN feedback has become a popular topic in the last decade, since theoretical models demonstrate that it can solve compelling problems of the most popular galaxy formation scenarios. However, little observational evidence exists to support such models. It is important to carry out deep spectroscopic and imaging studies of different AGN classes at different epochs to evaluate the role AGN feedback plays and disentangle the impact on the evolution of the host galaxies.
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We work on ground and space based study of the minor bodies of the Solar System, Trans-Neptunian objects (TNOs), asteroids and comets. This observational work is complemented with theoretical developments of the rotational state of the minor bodies, their interiors, shape, mass and density, all this having strong implications in constrain the origin of the solar system and its evolution.
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The role played by the environment in the evolution of galaxies remains an open issue: the so called " nature versus nurture " debate. At present, it is known that the environment where galaxies are located appears to have a decisive influence on several processes that regulate the kinematics and activity of star formation in galaxies. To disentangle which effects can be attributed to gravitational interactions the full characterization of a well defined baseline of isolated galaxies is still incomplete.
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Today there is increasing evidence that the evolution of massive galaxies is linked to their nuclear activity. This evidence is supported by: 1) the similarities between the evolution of the QSO luminosity density and the star formation rate; 2) the tight correlation between the black hole mass and the bulge stellar velocity dispersion.
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For an comprehensive view of the star formation the study of the interstellar medium is needed. In our group it is carried out including its different phases, from the distribution of cold gas, both molecular and atomic, the warm component of the HII regions, till the very hot gas responsible for the X-ray emission. For the warm ionized component, members of this group are international experts in the physical properties and chemical composition of the HII regions from different points of view: for individual regions, detailed studies of the internal structure can be carried out using mainly spectroscopy in the optical and ultraviolet ranges. Emission line fluxes can be measured and electron temperatures, density and chemical composition are derived. In addition, useful properties of the ionizing population can be inferred from these studies, incorporating theoretical photo-ionization modeling of the regions using photo-ionization codes. The study of the diffuse component of the ISM can be carried out using spectroscopy of emission and absorption lines (mainly in the ultraviolet), whereas for the study of the less dense and very hot component of the IGM we make use of measurements of X ray emission. Both measurements are provided by satellites.
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For an comprehensive view of the star formation the study of the interstellar medium is needed. In our group it is carried out including its different phases, from the distribution of cold gas, both molecular and atomic, the warm component of the HII regions, till the very hot gas responsible for the X-ray emission. For the warm ionized component, members of this group are international experts in the physical properties and chemical composition of the HII regions from different points of view: for individual regions, detailed studies of the internal structure can be carried out using mainly spectroscopy in the optical and ultraviolet ranges. Emission line fluxes can be measured and electron temperatures, density and chemical composition are derived. In addition, useful properties of the ionizing population can be inferred from these studies, incorporating theoretical photo-ionization modeling of the regions using photo-ionization codes. The study of the diffuse component of the ISM can be carried out using spectroscopy of emission and absorption lines (mainly in the ultraviolet), whereas for the study of the less dense and very hot component of the IGM we make use of measurements of X ray emission. Both measurements are provided by satellites.
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The IAA Cosmic Dust Laboratory is devoted to experimentally studying the angle dependence of the scattering matrices of dust samples of astrophysical interest. We are especially interested in mineral dust particles that are potential candidates for being present in the planetary and cometary atmospheres of the Solar System (e.g. olivines, pyroxenes, calcite, carbon, etc). Moreover, there is great interest in measuring aerosol samples that can affect the radiative balance of the Earth's atmosphere such as desert dust, volcanic ashes, and carbon soot.
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Clusters and groups of galaxies, as representations of the densest regions of the universe, are key environments to understand the evolution of galaxies as traced by their star formation history, intimately related to their morphology and gas content. Indeed it has been reported that the global star formation rates of spiral galaxies located in the innermost regions of nearby and intermediate-redshift clusters appear strongly depressed as compared to the results found for similar galaxies at larger galactocentric radii. Less information is available in the literature with respect to the evolution of the star formation activity of the population of dwarf galaxies in clusters. Metallicity is, with stellar mass, one of the fundamental physical properties of galaxies, reflecting the gas reprocessed by stars and any exchange of gas between the galaxy and its environment. The study of the relation between stellar mass and metallicity is central to our understanding of the physical processes that govern star formation in galaxies. There seems to be a well defined relation between mass and luminosity in the sense that more massive galaxies are also more metal rich. This holds at all redshifts, although for a given stellar mass, more distant galaxies appear less metal rich than local galaxies. Up to now, few works have been devoted to the study of the metal content of cluster star-forming galaxies; some of them show a different behaviour with respect to field galaxies, and this effect has been attributed to the action of the cluster environment.
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We are facing the study of the origin of water in the Giant Planets and Titan atmospheres by developing photochemical models whose output will be compared with the data provided by the HIFI (Herschel space telescope, ESA) during 2009 and beyond. Study of the surface, exosphere of Mercury, and their interaction, is being faced since 2007 as new research front. Our involvement in the Bepi Colombo mission will guarantee our success. As a new research line, we are working on the development of applications for the scientific exploitation of the data provided by the laser altimeter (BeLA) on board the Bepi Colombo mission. This data are related to Mercury geology, geodesy, interior and surface characteristics.
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The main goal of this reasearch is to improve our basic knowledge of the physical processes associated with the early stages of the star formation. In particular, we study the basic ingredients of the process of star (and planet) formation: gravitational collapse of envelopes of gas and dust, protoplanetary accretion disks, outflows, and maser emission. We analyze the differences and similarities between the low-mass and high-mass star formation, both from an observational and theoretical point of view, making a special emphasis in high-angular resolution studies.
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The main goal of this reasearch is to improve our basic knowledge of the late stages of stellar evolution. For low- and intermediate-mass stars, we study the short transition from the asymptotic giant branch (AGB) phase to the planetary nebula stage. The primary objective of this research is to understand the effects of the different shaping agents (stellar winds, fast collimated outflows, central star strong radiation field) in the formation of planetary nebulae and to assess their relative importance in different phases of the nebular evolution.