Recent Talks

In this work we have tried to verify what types of bulges are the descendants and the precursors of the bulges with blue colors observed at intermediate z. These may be the result of intense star formation in the central regions of the disks, related to the phenomenon of pseudo-bulges in the local universe or, alternatively, they may result from rejuvenation processes of old and red classical bulges, formed at high z, perhaps through secular evolution produced by internal or external agents. We can identify and distinguish between these processes analyzing the central surface brightness of the galaxies, μ₀. For the general bulge population in the local universe, color is strongly correlated with surface density, in the sense that redder bulges are denser. Classical bulges and pseudo-bulges occupy different regions in a color-μ₀ diagram. We have studied the redshift evolution of the relation between the colors and the central surface brightness for samples of spiral galaxy bulges selected from HST/ACS GOODS-N survey, and have analysed the ability of color-μ₀ diagram to segregate different types of bulges at z ~ 1. The results show that, up to z ~ 0.8, galaxy nuclear and global colors are strongly correlated with the central surface brightness and, therefore, with the central surface density, in the sense that denser bulges are redder. This suggests that these formed the bulk of their stars at earlier epochs than less dense bulges. For z > 0.8, we find an important fraction of galaxies with high central surface brightness and nuclear colors much bluer than the rest of the galaxy, which probably corresponds to episodes of strong nuclear star formation that may result in the growth of the bulges inside the disks. From simple evolution models we can infer that these nuclei with star formation evolve towards the formation/growth of moderate central surface brightness, intermediate color z ~ 0 pseudobulges rather than classical bulges. These models also argue against rejuvenation processes for z ~ 1 dense and old bulges.

En una parte preliminar se recordarán unos pocos hechos experimentales obtenidos durante las últimas décadas, con énfasis en fenómenos puramente cuánticos como el entrelazamiento y el teletransporte, y también algunos hechos matemáticos elementales, con énfasis en las matrices hermíticas y unitarias. En una segunda parte se presentará un modelo matemático de la noción de q-ordenador y de conceptos subordinados como puertas q-lógicas, q-computación y q-algoritmos programas, con énfasis en los ejemplos, incluyendo la q-transformada de Fourier y el q-algoritmo de Shor de factorización en tiempo polinómico de números enteros positivos. A continuación se sumarizará un enfoque axiomático de la mecánica cuántica y se usará para relacionar las q-nociones anteriores con sus posibles realizaciones físicas, con énfasis en algunos problemas abiertos y en posibles líneas de trabajo futuro. La base de este material es la tesis de máster de Juanjo Rué,  "Un modelo matemático para la computación cuántica: fundamentos, algoritmos y aplicaciones" (julio de 2007), dirigida por Lluís Torner y el conferenciante.

I will propose a new theory to explain the formation and properties of rings and spirals in barred galaxies, focusing on a comparison of theoretical results to observations and giving some predictions for further comparisons. This theory can account for both spirals and rings, the latter both inner and outer. The model outer rings have the observed R₁, _{R_1'}, _{R_2}, _{R_2'} and _{R_1R_2} morphologies, including the dimples near the direction of the bar major axis. It explains why the vast majority of spirals in barred galaxies are two armed and trailing and I will discuss what it takes for higher multiplicity arms to form. The shapes of observed and theoretical spirals agree and the theory predicts that stronger non-axisymmetric forcings at and somewhat beyond corotation will drive more open spirals. I will compare the ratio of ring diameters in theory and in observations and predict that more elliptical rings will correspond to stronger forcings. This theory also provides the right building blocks for the rectangular-like bar outline and for ansae.