Recent Talks

El estudio de la radiación cósmica ha sido la herramienta fundamental para avanzar en el conocimiento del Universo. La instrumentación experimental ha sido muy variada utilizándose para su ubicación laboratorios convencionales, globos sonda, satélites y plataformas espaciales. Está previsto que en 2011 la Estación Espacial Internacional esté totalmente operativa y disponible para la realización de medidas precisas y de larga duración de las componentes electromagnética y cargada de la radiación cósmica en ausencia de contaminación atmosférica. Una colaboración internacional ha construido un detector de física de partículas elementales, el espectrómetro AMS−02, para la realización de este tipo de medidas, algunas de las cuales tienen extraordinario interés en Astrofísica de Partículas, una disciplina científica fronteriza entre la Física de Partículas Elementales, la Astrofísica de Altas Energías y la Cosmología. En la planificación de la NASA este instrumento será enviado a la Estación Espacial en el año 2011. En esta conferencia se describirá la Estación Espacial Internacional (ISS) y el programa científico de AMS−02, en particular la búsqueda de antimateria cósmica primaria y la posible observación de señales de materia oscura.

El azar es un concepto fascinante que atrae el interés de diversas comunidades, desde filósofos a físicos y matemáticos. Por otro lado, los números aleatorios se han convertido en un recurso de gran utilidad práctica, puesto que son utilizados en, por ejemplo, aplicaciones criptográficas o la simulación de sistemas físicos y biológicos. Hasta ahora, cualquier propuesta para la generación de números aleatorios adolece de los siguientes problemas: (i) certificación: ¿cómo se puede probar que los números generados son aleatorios?, (ii) privacidad: ¿cómo se puede garantizar que los números aleatorios son aleatorios, en el sentido de impredecibles, a cualquier otro observador externo y (iii) device-independent: ¿cómo afectan las imperfecciones en los dispositivos al proceso de generación de azar? En la charla se presentará un nuevo formalismo para la generación de azar que resuelve estos tres problemas: por medio de las correlaciones no-locales de los estados entrelazados, es posible generar números cuya aleatoriedad es certificable, privada e independiente de los dispositivos.

I present a general overview of the PLAnetary Transits and Oscillations of stars (PLATO) space mission. PLATO was approved by ESA’s Science Programme Committee, together with Euclid and Solar Orbiter missions, to enter the so-called definition phase, i.e. the step required before the final decision is taken (only two missions will be implemented). To be launched in 2018, PLATO is a third generation mission, which will take advantage of the scientific return from the currently flying space missions CoRoT (CNES, ESA, launched in 2006), and Kepler (NASA, launched in 2009). Moreover, the preparation and exploitation of the missions will benefit from the GAIA (ESA) mission data, together with new generation ground-based instrumentation like North-HARPS, GIANO, CARMENES, etc. Finally, I summarize the current organization status of the mission,focusing on the Spanish role within the consortium.

Spectroscopic analysis of stellar populations is widely used to understand the history of many systems including globular clusters, nuclear star clusters, dwarf galaxies through to giant galaxies over a wide range of redshifts. In this talk I first explore aspects of stellar population fitting, focussing on the effects of interacting binary stars on the yields and hence the spectra of early-type galaxies. The second part of the talk concentrates on what we know about supernovae type Ia and the importance of understanding their contributions to the chemical evolution of galaxies and stellar populations.

In recent years, major changes were done at the IRAM Plateau de Bure interferometer and 30-meter telescope, in particular in the areas of receivers and back-ends. These enhancements increased in significant ways both the sensitivity and the efficiency of both IRAM facilities. I will present results obtained on high-z (2 < 6.4) sub-millimeter galaxies and quasars that illustrate the progress that has been made, emphasizing recent follow-up observations of sources that were uncovered in the Herschel surveys. The talk will end with a presentation of the future projects that are currently under discussion at IRAM, including the NOrthern Extended Millimeter Array (NOEMA), as well as the prospects offered by ALMA.

Dark Matter in Galaxies is an important subject of current astrophysical research. I will concentrate on spiral galaxies, and first give an overview of the subject from the standpoint of a radioastronomer with a long involvement in the subject. This includes a historical introduction and a review of some of the present-day debates. The currently popular Lambda-CDM model has problems on the scale of galaxies. In a second part I will address more specifically the problem that we still do not know how much dark matter there is in spiral galaxies, and how it is distributed. This is due to the fact that the M/L of the visible matter is poorly constrained and that there is a 'conspiracy' between the dark and the baryonic material. I will present various dynamical methods that have been proposed to constrain the dark matter mass distribution and discuss their advantages and disadvantages.

The detection and number estimates of supermassive binary black holes (SMBBHs) provide important constraints on the hierarchical models for galaxy formation and evolution. I will present two different approaches for the possible identification of SMBBHs. 1.Radio-optical studies of X-shaped radio sources:X-shaped radio galaxies are extragalactic radio sources that present two pairs of radio lobes passing symmetrically through the center of the host galaxy, giving the galaxy the X-shaped morphology seen on radio maps.This morphology can reflect either a recent merger of two supermassive black holes or the presence of a second active black hole in the galactic nucleus. This scenario is studied by determining the mass, luminosity, jet dynamic age and starburst of a sample of X-shaped sources and comparing the results to a sample of radio-loud active nuclei with similar redshift and luminosities. 2.Compact radio emission in ULX objects: Ultraluminous X-ray sources (ULXs) have luminosities exceeding 10E39 erg/s, suggesting either the presence of black holes larger than stellar mass black holes or sources apparently radiating above the Eddington limit. I will present milliarcsecond-scale radio observations of some ULXs located within optical bright galaxies, resolving their compact radio emission, and measuring its brightness temperature and spectral properties. This allows us to uncover the nature of these sources and investigate whether they are intermediate mass black holes or supermassive black holes stripped of their accretion disks in post-merger systems.

3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was re-observed by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from the Fermi space telescope on an exceptionally high gamma -ray state. The January 2007 observations resulted in a detection on January 16 with significance 5.2 sigma, corresponding to a F(> 150 GeV)(3.8±0.8) 10^-11 ph cm^-2 s^-1 while the overall data sample does not show significant signal. The December 2008 - April 2009 observations did not detect the source. We study the multi-wavelength behaviour of the source at the epochs of MAGIC observations, collecting quasi-simultaneous data at optical and X-ray frequencies and for 2009 also gamma-ray data from Fermi. We study the light curves and spectral energy distribution of the source. The spectral energy distributions of three observing epochs (including the February 2006, which has been previously published in Albert et al. 2008a) are modelled with one-zone inverse Compton models and the emission on January 16, 2007 also with two zone model and with a lepto-hadronic model. We find that the VHE gamma-ray emission detected in 2006 and 2007 challenges standard one-zone model, based on relativistic electrons in a jet scattering broad line region photons, while the other studied models fit the observed spectral energy distribution more satisfactorily.

According to Quantum Chromodynamics, which is the well established theory of strong interactions, quark and gluons are forced to live inside hadrons because of the property of confinement. However, under extreme conditions of temperature and pressure, a new phase called quark-gluon plasma is possible, where quarks and gluons became basically free. In the last years it has been possible to study this phase experimentally by using new facilities called Heavy Ion Colliders like the RHIC (Brookhaven) or the LHC (CERN).

Los habitantes del País de Hatti, contemporáneos y rivales de los egipcios del Reino Nuevo, produjeron durante varios siglos una sofisticada cultura heredera de la larga tradición anatolia y que perduraría en diversos reinos después de su caída a finales del siglo XIII a. de C. A pesar de la importancia de ciertos dioses con un claro trasfondo celeste, tales como la Diosa Solar de Arinna, hasta el presente no se habían realizado trabajos para investigar esta dimensión en su cultura. En la presente charla realizaremos un repaso a algunos de estos elementos astrales de la religión y cultura Hitita, así como presentaremos los resultados de la campaña que llevamos a cabo in situ en el verano de 2009, recientemente aceptados para su publicación en JHA. Los resultados muestran que la orientación adecuada de templos, espacios funerarios y otros monumentos era de especial relevancia a lahora de cumplir con los requisitos religiosos. En particular, noscentraremos en los monumentos de la ciudad de Hattusa, la capital Hitita, y sus alrededores.