Seminars
Scientific seminars exposed by scientists and technologists of the IAA and the many centers and research institutions who visit us. They show the intense scientific exchange, they are held at 12:30 every Thursday. Seminars are broadcasted live at IAA - CSIC Seminars Live.
For further information, please contact seminars (at) iaa.es.
Displaying 851 - 900 of 1201
Pages
|
12/06/2002 - 14:00
A review of the fundamental problem of galactic dynamics The dynamics of stellars systems is fully specified by its distribution function - the phase density of its consistuent stars - and the form of the gravitational potential that binds it together. The so-called fundamental problem of galactic dynamics is the recovery of this information from the observable properties of a galaxy. I will review past results concerning this problem in the spherical and axisymmetric geometry. Finally I will show my... Anne Mathieu |
|
27/05/2002 - 14:00
Evolución química en galaxias enanas esferoidales y su importancia en el medio intergaláctico del Grupo Local Se han modelado quimicamente 4 galaxias enanas esferoidales (dSph) satelites locales a partir de historias de formacion estelar obtenidas de sus diagramas HR. Se encuentran restricciones sobre la cantidad de materia oscura en estas galaxias, los tipos de vientos galacticos acontecidos y detalles de la tasa de la formacion estelar en los primeros tiempos evolutivos. Basandose en el material expulsado por el bulbo Galactico y por las galaxias... Leticia Carigi |
|
24/05/2002 - 14:00
Star formation, gas cycles and the chemical evolution of dwarf irregular galaxies Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences from internal and external sources. In gas-rich dwarf irregular galaxies not only that star formation regulates itself due to the stellar energy release, but also supernova-driven galactic winds are accepted as a general explanation for their low metallicities. Chemodynamical models of dIrrs that take the dynamics of different gas phases and... Gerhard Hensler |
|
17/05/2002 - 14:00
Hipparcos y la población estelar temprana de la vecindad solar: Estructura vertical galáctica, la burbuja local y extinciones masivas. The availability of Hipparcos data has revolutionized astrometry. The impact has been felt more strongly in those fields where there is a significant number of objects within 200 pc, which corresponds to the maximum distance at which individual Hipparcos parallaxes can be considered accurate. However, objects located further away can still be analyzed with Hipparcos when one considers the measurements in a statistical sense. Here I discuss some... Jesús Maíz Apellániz |
|
14/05/2002 - 14:00
La compleja vida de las galaxias elípticas We present a simple phenomenological model of feedback in early-type galaxies that tracks the evolution of the gas content, metallicity and temperature. Modeling the star formation rate as a Schmidt law with a temperature-dependent efficiency, we find that intermittent episodes of star formation are common in moderate-size ellipticals. This departure from a standard scenario of passive evolution implies significantly younger luminosity-weighted... Ignacio Ferreras |
|
10/05/2002 - 14:00
Gas molecular y formación estelar en galaxias enanas de marea Tidal Dwarf Galaxies (TDGs) are created during a violent interaction of galaxies containing at least one spiral. Atomic hydrogen is torn off a spiral and star formation takes place in this gas which accumulates at the ends of tidal tails. TDGs typically contain two main stellar components: young stars recently formed by collapse of expelled HI clouds, and an older stellar population, at least 1 Gyr old, which was pulled out from the disk of the... Ute Lisenfeld |
|
25/04/2002 - 14:00
Nuclear star clusters in late-type spirals I will summarize the results of our recently completed HST/WFPC2 I-band survey of a sample of 77 nearby, late-type spiral galaxies with low inclination. The main purpose of this catalog is to study the frequency and properties of nuclear star clusters in this class of galaxies. We find that at least 75% of late-type spirals harbor a distinct, compact (but resolved), and dominant star cluster at their photocenter. From an isophotal analysis, we... Torsten Boeker |
|
24/04/2002 - 14:00
New results from Plateau de Bure Tbd Michel Guelin |
|
17/04/2002 - 14:00
Solar Terrestrial Physics Laboratory at CRESS, York University, Canada Tbd Stoyan Sargoytchev |
|
16/04/2002 - 14:00
La calibración de ALMA: Efectos atmosféricos, su modelización, medida y estrategias de corrección El proyecto ALMA exigirá grandes esfuerzos tanto en el dominio técnico como en el de la modelización que deberá simular o tratar ciertos efectos. Uno de los problemas a abordar es el de los efectos atmosféricos sobre las observaciones: atenuación, contribución a la temperatura de sistema, fluctuaciones de la fase... Disponer de un modelo lo más preciso posible de dichos efectos atmosféricos y trabajar sobre las estrategias más convenientes para... Juan Ramón Pardo |
|
02/04/2002 - 14:00
Dwarf Galaxies: the building blocks of the Milky Way? In hierarchical clustering scenarios of galaxy formation, such as cold dark matter-dominated cosmologies (White and Rees 1978), dwarf galaxies should have formed prior to the epoch of giant galaxy formation and would be the building blocks of larger galaxies. The picture of building the Galactic halo from merging ``fragments'', which Searle and Zinn (1978) proposed on the basis of the properties of the Milky Way globular clusters, is regarded as... David Martínez Delgado |
|
20/03/2002 - 13:00
Astronomy in Egypt Tbd Anas Osman |
|
13/03/2002 - 13:00
La evolución del He4 y del Helio primordial En esta charla voy a revisar la evolución del 4He en el Universo, con un énfasis particular en la determinación de la abundancia de Helio primordial Y_P y sus implicaciones cosmológicas. Discutiré las determinaciones más recientes de Y_P, y las incertidumbres que las afectan. Valentina Luridiana |
|
04/03/2002 - 13:00
Proyecto ALMA Tbd José Cernicharo |
|
29/01/2002 - 13:00
Los cometas y el agua terrestre Resultados de observaciones cometarias recientes han estimulado varias hipotesis nuevas sobre el origen de la materia volatil terrestre, incluyendo el agua, moleculas organicas y gases nobles. Se ha sugerido (por ejemplo, Owen and Bar-Nun 1995 y 2000, Delsemme 1999) que los cometas son la fuente principal del agua y de las primeras moleculas organicas terrestres. Por otro lado, Swindle y Kring (2001) se basan en la abundacia de Argon observada... Humberto Campins |
|
15/01/2002 - 13:00
Estrellas, emisión multirango y estadística: hacia una nueva generación de modelos de síntesis Los modelos de sintesis evolutiva son una herramienta que se aplica para determinar las propiedades fisicas de un amplico rango de objetos, desde cumulos estelares a galaxias a distancias cosmologicas. Su principal ventaja es la capacidad de obtener las propiedades promedio de sistemas estelares en funcion de cierto numero de parametros y la capacidad de comprobar nuestro conocimiento sobre la teoria de evolucion estelar mediante la comparacion... Miguel Cerviño Saavedra |
|
09/01/2002 - 13:00
El gas más caliente en nebulosas planetarias: revelaciones en rayos X y UV Las nebulosas planetarias son el resultado de la evolucion de estrellas de masa baja e intermedia. El modelo mas aceptado para explicar la formacion de las nebulosas planetarias es el de la interaccion entre el viento estelar rapido y tenue que emana de la estrella central con el viento lento y denso que se eyecto en fases anteriores de la evolucion estelar. Una de las predicciones basicas de este modelo es que el viento estelar en el interior... Martin A. Guerrero |
|
18/12/2001 - 13:00
The Martian atmospheric evolution: implications for the planetary water inventory The study of Mars and its planetary water inventory is particularly interesting because this planet is similar to Earth in many ways. Observations by various spacecraft in the past and more recently by Mars Global Surveyor showed the probable existence, at least in the past, of large quantities of liquid water on the Martian surface or in subsurface layers. Surface features resembling massive outflow channels provide evidence that the Martian... Helmut Lammer |
|
17/12/2001 - 13:00
Searching for signatures of life on extra-solar plantes The direct detection of terrestrial extra-solar planned should be possible in the next 10 or 20 years. It is the main purpose of two space missions: Darwin (ESA) and TPF (NASA). Moreover, assuming a detection of such a planet, these telescopes should also be able to perform low-resolution spectra of this new world and therefore to infer the presence of atmospheric compounds. I will discuss the exobiological implications of these extrasolar... Franck Selsis |
|
22/11/2001 - 13:00
Cúmulos estelares en regiones de HII extragalácticas This talk deals with properties of very young (< 10-20 Myr) stellar clusters which are in the nebular phase and are embedded in photoionized regions (classical extragalactic HII regions (RHIIs) or starburst galaxies). Based on the analysis of the integrated light of these clusters at the UV and optical wavelengths, different techniques are discussed that allow to estimate in consistent the stellar content and the evolutionary state of the... Rosa González Delgado |
|
16/11/2001 - 13:00
The Rayleigh ellipsoid approximation. A poor man's approach to the extinction of electrogmanetic radiation by small particles. Tbd Andrzej Jurewicz |
|
14/11/2001 - 13:00
Non-adiabatic eigenfunctions in the atmosphere of pulsation stars: a tool for better mode identification. In this seminar, an overview of the utility of studying non-radial non-adiabatic oscillations of stars such as $\delta$ Scuti, $\beta$ Cephei and Slowly Pulsating B stars will be given, with a particular attention on the problem of mode identification. Then I will present in more details the particularities of the non-adiabatic code I have written, which is mainly the special care given to the modelling of the pulsation in the atmosphere. Antoine Dupret |
|
07/11/2001 - 13:00
Enigmática expulsión esférica de materia en un embrión estelar. ALMA, una gran espectativa. Tbd José María Torrelles Arnedo |
|
06/11/2001 - 13:00
The Hamburg/SAO survey for low metallicity BCGs (HSS-LM) The description and the first results of the new project will be presented. It is devoted to the search for the most metal-deficient blue compact galaxies. The first goal is to extend the sample of the most interesting candidates to truly young galaxies in the local Universe, and study them in detail. The second goal of the project is to create a large, clearly selected sample of BCGs with reliably measured O/H. The data will be used for the... Simon Pustilnik |
|
24/10/2001 - 14:00
Acreción y pérdida de masa cerca del límite subestelar LS-RCrA 1 es una estrella de tipo espectral muy tardío (M6.5-M7) cuyo espectro muestra líneas de emisión muy intensas, tanto prohibidas como permitidas. La estrella parece encontrarse en una región de formación estelar, lo que explicaría la presencia de las líneas, pero su posición en el diagrama HR, teniendo en cuenta las trazas evolutivas calculadas para estrellas de muy baja masa, difiere de la esperada. Matilde Fernández |
|
02/10/2001 - 14:00
The evolution of galaxies in different cosmological environment According to the hierarchical scenario, galaxies form via merging and accretion of small objects. Within a series of high resolution simulations we have studied the formation and evolution of dark matter halos hosting galaxies. First halos have been formed at z > 10. We have studied the evolution of isolated halos (field galaxies) as well as of halos in dense regions (galaxies in groups or clusters and galaxies with satellites) and of small... Stefan Gottloeber |
|
26/09/2001 - 14:00
Perspectivas científicas con VLBI a longitudes de onda milimétricas Tbd Antxon Alberdi |
|
12/09/2001 - 14:00
Interacción de meteoroides con las atmóferas de Marte y Titán Tbd Gregorio Molina |
|
04/07/2001 - 14:00
El instrumento OSIRIS de la misión Rosetta Tbd Rafael Rodrigo |
|
28/06/2001 - 14:00
The problem of stability of internal spaces in multidimensional cosmology We investigate effective 4-dimensional theories which were obtained under dimensional reduction of multidimensional cosmological models. We show that for warped product spacetimes the conformal (geometrical moduli) excitations of the internal spaces should be observable as massive scalar fields in the external (our) spacetime. These scalar fields (gravitational excitons) describe weakly interacting particles and can be considered as dark matter... Prof. Alexander Zhuk |
|
27/06/2001 - 14:00
High-Energy Emission from Relativistic Jets in Blazars We have been observing a number of blazars with the Very Long Baseline Array in concert with monitoring at other wavebands, including X-rays and gamma-rays. Observations over several years demonstrate that there is an intimate connection between the ejection of apparent superluminal knots in the relativistic jets and X-ray or gamma-ray flares in blazars. The high-energy emission tends to be simultaneous with or even to follow the radio event,... Prof. Alan Marscher |
|
26/06/2001 - 14:00
Some aspects of the upper atmosphere of Mars: ionosphere, airglow, meteors. The comparative study of the planetary atmospheres is a young and interesting science, because of the diversity of the situations. As part of this programme, the exploration of Mars is very challenging. This talk concerns more particularly the modeling of the Martian ionosphere, in the context of the future missions to Mars (Mars-Express, Nozomi, Netlander, Mars 2007). The ionospheric model is based on a terrestrial coupled kinetic and fluid... Olivier Witasse |
|
22/06/2001 - 14:00
Panorama de la Gravedad Cuántica El objetivo fundamental de esta charla es promover un acercamiento entre las comunidades observacional y teórica de este Instituto. Con la sensibilización como meta previa, se realizará un recorrido por la situación actual de la investigación en Gravedad Cuántica, enfatizando los aspectos conceptuales de las principales aproximaciones al problema y motivando las correspondientes soluciones técnicas. José Luis Jaramillo |
|
13/06/2001 - 14:00
Unificación no trivial de las fuerzas electromanéticas y gravitatorias El principio de mínima interacción es revisado en un marco grupoteórico. Al imponer la invariancia "local" bajo traslaciones espaciotemporales del lagrangiano de la partícula libre después de haber extendido centralmente el grupo de Poincare por U(1) (invariancia de fase en Mecánica Cuántica) aparece una nueva fuerza de tipo electromagnético pero de origen puramente gravitatorio. Esto constituye un paso hacia la mezcla de simetrías... Víctor Aldaya |
|
08/06/2001 - 14:00
Corrugaciones En esta charla se hará una revisión del concepto de corrugación como fenómeno universal que afecta a los discos de las galaxias espirales y se plantean diversas estrategias para dirimir su origen y estructura. Emilio Alfaro Navarro |
|
23/05/2001 - 12:00
Retrieval of atmospheric parameters from MIPAS/ENVISAT emission spectra at 5.3 um under non-LTE conditions In (hopefully) 5 months ESA's polar platform ENVISAT will be launched. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is one of the core instruments and will continously record high resolution emission spectra of the Earth's atmosphere. Vertical profiles of temperature and various trace gases relevant to stratospheric chemistry are planned to be retrieved from the data. The talk will give a summary on the status of the... Bernd Funke |
|
18/05/2001 - 14:00
Evolution of Pulsar Magnetic Fields Because canonical neutron stars consist mainly of superfluid neutrons, superconducting protons and extremely relativistic electrons, all enclosed by a thin solid crust, the magnetic field structures of these stars vary in predictable ways during stellar spin-up and spin-down. Predicted consequences will be compared to a variety of observations of regular and millisecond pulsars including sudden changes in pulsar spin-periods ("glitches... Prof. Malvin Ruderman |
|
09/05/2001 - 14:00
Procesos de 'scattering' múltiple en comas cometarias Los modelos dinámicos multifluido realizados hasta la fecha para el cálculo de la distribución de gas y polvo en las comas cometarias rodeando núcleos no esféricos no tienen en cuenta el efecto del "scattering" múltiple de la luz solar por las partículas que rodean al cometa. Nuestras estimaciones indican, sin embargo, que la profundidad óptica en el visible en condiciones subsolares, en las comas de ciertos cometas con elevado... Fernando Moreno |
|
02/05/2001 - 14:00
Recent Water Activity on the Surface of Mars There are two known reservoirs of water on Mars: the atmosphere, and the north polar cap. The latter contains possibly as much as 10 meters of water (global ocean equivalent). What happens to this water at high obliquity? Mars' obliquity varies chaotically on time scales greater than 10 million years and may have been as high as 60 degrees. We use a general circulation model with a simple hydrological cycle to address this question. We find that... Robert Haberle |
|
24/04/2001 - 14:00
Seminario-coloquio Seminario-coloquio Prof. Dr. Stephen Hawking |
|
18/04/2001 - 14:00
Is the universe fractal or homogeneous on large scales? The debate about the possible smoothness of the Universe on large scales as opposed to an unbounded fractal hierarchy has been the subject of increasing interest in recent years. The controversy arises as a consequence of different statistical analyses performed on surveys of galaxy redshifts. I review the observational evidence supporting the idea that a gradual transition occurs in the galaxy distribution: from a fractal regime at small scales... Vicent Martínez |
|
04/04/2001 - 14:00
Arc-shaped star complexes in galaxies There exist isolated star complexes , located sometimes far away from the center of a galaxy or from the spiral arms. These complexes often have spheroidal or arc-like shapes. The best examples are in the LMC, NGC 6946 and NGC 5236. This shape strongly suggests triggering by some energetic events. The striking feature of these complexes is their sharp and circular outer edge. This suggests they are partiall spheres and could be formed from the... Yuri N. Efremov |
|
21/03/2001 - 13:00
Stephan's Quintet: Anatomy of a Multiple Galaxy Collision. We present old and new unpublished multiwavelength data for the most famous compact group of galaxies. Such groups are ideal laboratories for studying the effects of strong interactions. The data suggest an evolutionary history that may have general relevance to the compact group phenomenon and to interaction phenomena in the early Universe. The data suggest that SQ has been visited by two intruders in the past Gyr. The first intruder stripped... Jack Sulentic |
|
16/03/2001 - 13:00
Moléculas y anillos aromáticos en el espacio Tbd José Cernicharo |
|
08/03/2001 - 13:00
Un método para la alineación del telescopio de 1.5m de San Pedro Mártir Tbd Leonel Gutiérrez |
|
07/03/2001 - 13:00
WeCAPP: Wendelstein Calar Alto Pixellensing Project: Capturing dark matter in M31 I present (WeCAPP) our long time project searching for microlensing events in M31. Since 1997 the bulge of M31 was monitored in two different wavebands with the Wendelstein 0.8 m telescope. In 1999 we extended our observations to the Calar Alto 1.23m telescope. Observing simultaneously on these two sites we obtained a larger than 60% time coverage of the visibility of M31. To check thousands of frames for variability of unresolved sources, we... Arno Riffeser |
|
21/02/2001 - 13:00
El campo magnético de las manchas solares En esta charla trataré de repasar y resumir nuestros conocimientos más actuales acerca del campo magnético de las manchas, de su estructura tridimensional, del transporte energético a través de su atmósfera, así como de las relaciones del campo magnético con los fenómenos dinámicos más importantes que tienen lugar en la fotosfera de las manchas. José Carlos del Toro Iniesta |
|
15/02/2001 - 13:00
Eigenvector 1: An H-R Diagram for AGN? Most Active Galactic Nuclei (AGN) are characterized by the presence of broad emission lines. However the AGN definition includes a wide range of phenomenologies, both radio-loud and radio-quiet. We report on exciting new developments that unify all classes of AGN showing broad lines. Correlations in this "Eigenvector 1" parameter space appear to be driven primarily by the accretion rate onto the supermassive black holes that power... Jack Sulentic |
|
07/02/2001 - 13:00
Eyecciones colimadas en nebulosas planetarias y estrellas centrales binarias En la eyección de muchos de los flujos colimados observados las nebulosas planetarias parecen estar involucradas estrellas binarias. Sin embargo, el número de estrellas centrales binarias que se conocen es escaso y la detección de binarias puede ser difícil observacionalmente. Una forma de inferir la presencia de una estrella central binaria es estudiar su influencia en las propiedades nebulares. Presentamos dos nebulosas planetarias (IC4846 y... Luis F. Miranda |
|
31/01/2001 - 13:00
INTEGRAL: El Observatorio Astronómico Europeo de Altas Energías En Abril de 2002 está previsto el lanzamiento de la misión INTEGRAL de la ESA, que operará durante al menos 5 años cubriendo todo el rango desde los 3 keV hasta los 10 MeV, con una sensibilidad sin precedentes a Altas Energías, lo que permitirá investigar nuevos fenómenos violentos en el Universo. Las propuestas para el Primer Anuncio de Oportunidad se han de presentar antes del 16 de Febrero de 2001. Alberto Castro Tirado |