Recent Talks

The general picture of galaxy formation and evolution includes bars as the main drivers of the internal secular processes affecting the lifetime of disc galaxies. Bars are present in a very high fraction of all the spiral galaxies found at different redshifts, and the processes inducing their formation or the effects they may have on their host galaxies are still under discussion. Particularly interesting is the case of double-barred galaxies: at least 20% of all spirals have turned out to host not only one but two bars embedded in them. These two bars appear randomly oriented and independently rotating. The formation of such a double-barred system has been the goal of several numerical simulations and the results obtained so far can be roughly divided in two big groups: gas-rich and gas-free formation scenarios. In the same way a single bar does, double-bar systems might also promote gas inflow and contribute to the internal secular evolution. Moreover, they have also been proposed as a very efficient mechanism for the feeding of the active galactic nuclei.

All the previous theoretical hypothesis on the formation and evolution of double-barred galaxies have not been tested due to the lack of observational works focused on these systems. With this motivation, during my PhD I observed a sample of double-barred galaxies in order to fully analyse their kinematics and stellar populations. Among the most interesting results, it is important to highlight the discovery of the sigma-hollows, which are the only known kinematical signature of the presence of inner bars, or the fact that inner bars are younger and more metal-rich than their surrounding regions. In this talk I will present the whole work and discuss the results in the framework of the different formation scenarios and the role that these inner bars may be playing in the evolution of their host galaxies.

En esta charla se abordarán herramientas de interés para el desarrollo de actividades en línea con equipos de trabajo ubicados es espacios geográficos diferentes. Se darán a conocer herramientas de utilidad para el trabajo en la nube, especialmente en aquellos casos en los que tenemos que contactar con personas ubicadas en espacios geográficos distintos.

We discuss the role and significance of molecules in the modern astrophysics. Molecular opacities govern the structure of model atmospheres of late-type stars and ultracool dwarfs. Some problems of computations of model atmosphere and synthetical spectra of cool stars are discussed. We present some successful attempts of the application of the molecular spectroscpy for the studies of late -type stars and ultracool dwarfs. Finally, some problems of fitting theoretical spectra to the observed SED are discussed.

Neutron stars in low-mass X-ray binaries (NS-LMXBs) are unique laboratories of accretion physics, strong gravity and ultra-dense matter. I will give an overview of what we have learned in recent years by studying accretion flows and thermonuclear bursts in these systems.

I will first present and discuss the main result of a systematic study of their different accretion states: the discovery of a correlation between luminosity and spectral hardness. I will also show ongoing work on the connection between active (1-100% of the Eddington luminosity) and quiescent (down to 10^-6 times Eddington) phases of NS-LMXBs.

In the second part I will focus on the relation between mass accretion rate and the recurrence time of thermonuclear bursts (explosive nuclear burning on the neutron star surface), presenting results at the lowest and highest mass accretion rates. In particular, I will argue that rotation plays a larger role than we thought in setting the nuclear burning regimes on an accreting neutron star.

Among the different effects of secular evolution of galaxies we find how bars influence enormously their host galaxies. For many years now, it is known how the evolution of bars will produce different boxy/peanut and X-shape bulges. In this context our Milky Way is an example of a boxy bulge, and we will present a self consistent N-body simulation of a barred galaxy that will be compared with some of the Milky Way available data. We will compare the model in terms of morphology and structure, kinematics and finally metallicity gradients.

1) Overview on Planck and QUIJOTE. R. Rebolo 15 min. 2) The Galaxy as seen by Planck. R. Génova-Santos 15 min. 3) Planck Cosmological Results. J. A. Rubiño-Martín 20 min (times approximate). We will give an overview of two Cosmic Microwave Experiments with a significant involvement of the IAC. The ESA mission Planck has recently released its first set of Cosmological Results. QUIJOTE is a CMB polarization experiment which has recently started scientific operation at Teide Observatory. We will show the first results and the potential of QUIJOTE and we will provide an overview of the Planck mission and its impact on Galactic science and on Cosmology.

Although there is increasing speculation that the evolution of galaxy bulges may be regulated by AGN-induced outflows associated with the growth of the central supermassive black holes, the importance of AGN-induced outflows relative to those driven by starbursts has yet to be established observationally. In this context we have recently presented a study focusing on AGN-induced outflows in a sample of local Seyftert-ULIRGs. Perhaps, our most interesting result is related to the energy that the AGN returns to the galaxy in the form of feedback. We find that the typical mass outflows rates and kinetic powers of the emission line outflows are, in general, less energetically significant than the neutral and molecular outflows in ULIRGs and moreover, than those required today in the majority of the current hydrodynamic simulations that include AGN feedback. However, the uncertainties in the existing measurements are large, and more accurate estimates of the radii, densities and reddening of the outflows are required to put these results on a firmer footing. In this context, we are using HST /ACS+STIS and VLT-Xhsooter observations to accurately estimate sizes, electron densities and reddening to eventually provide the most accurate estimates of the kinetic powers associated with the ionized gas. In this talk I will describe in detail the results of this study focussing on testing the current simulations of hierarchical galaxy evolution.

How do the first galaxies form and evolve? Optical and near-infrared deep surveys are now finding galaxies at very high redshifts. However, they are typically small, not massive and present some but not very high star formation. But now the Herschel Multi-tiered Extragalactic Survey (HerMES), the largest project that has being carried out with the Herschel Space Observatory, in collaboration with other groups, has discovered a massive, maximum-starburst galaxy at a redshift of 6.34. The presence of galaxies like HFLS3 in the early Universe challenges current theories of galaxy fomation and evolution. I will describe the method we have developed to find these galaxies, the follow-up observations with different facilities and the main physical properties of this extreme object.

Taking advantage of the ultra-deep near-infrared imaging obtained with the Hubble Space Telescope on the Hubble Ultra Deep Field, we detect and explore for the first time the properties of the stellar haloes of two Milky Way-like galaxies at z~1. We find that the structural properties of those haloes (size and shape) are similar to the ones found in the local universe. However, these high-z stellar haloes are approximately three magnitudes brighter and exhibit bluer colours ((g-r)<0.3 mag) than their local counterparts. The stellar populations of z~1 stellar haloes are compatible with having ages <1 Gyr. This implies that the stars in those haloes were formed basically at 1<z<2. This result matches very well the theoretical predictions that locate most of the formation of the stellar haloes at those early epochs. A pure passive evolutionary scenario, where the stellar populations of our high-z haloes simply fade to match the stellar halo properties found in the local universe, is consistent with our data.

Total spectral irradiance is typically modeled by assinging an atmospheric model to each pixel of a full disk image and geometricllay combining the predicted wavelength dependent intensity for each of these models into a disk integrated spectrum. This works reasonably well, as the hydrostatic models that are used in this procedure generally reproduce observed spectra very well. However, for numerical expedience this scheme neglects some important physical aspects of the the solar atmosphere, in particular its three-dimensional and strongly dynamic nature. In this talk I will discuss the importance of some of these effects on the spectral irradiance signal, using forward radiative transfer modeling in realistic three-dimenional simulations. Obviously, modeling the three-dimensional dynamic structure over the whole disk is computaionally prohibitive, but if some of the effects discused above are important, strategies will have to be implemented to incorporate them approximately. Characterizing these cotributions to the spectral irradiance will also help us to better understand the physical nature of the forces that drive variability, and hopefully improve our predictive capabilities.