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.

 

Guidelines

For further information, please contact seminars (at) iaa.es.

Displaying 851 - 900 of 1227



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22/04/2003 - 14:00
Astrosismología no adiabática en estrellas Delta Scuti y fotometría multicolor
La astrosismología es una de las herramientas más potentes que tenemos para el estudio de la estuctura interna de estrellas aisladas. Esta se ha basado hasta ahora en la observación de las frecuencias de oscilación estelar y en el ajuste e identificación de estas observaciones mediante modelos teóricos. Pero para la mayor parte de las estrellas el solo ajuste de las frecuencias no es suficiente. Recientemente se ha puesto al dia otro método...
Andrés Moya Bedón
04/04/2003 - 14:00
Basic ingredients for the biggest blasts in the cosmos
There is now general agreement that gamma-ray bursts involve extraordinary power outputs, posing a severe theoretical challenge and - irrespective of which detailed model proves correct - involving some fascinating and extreme physical processes. I shall focus on some of the key issues relating the modeling of the trigger and the formation of the ultra relativistic outflow which has been proven to be a formidable challenge to computational...
Enrico Ramírez Ruiz
28/03/2003 - 13:00
Cinemática y dinámica de pares aislados de galaxias: observaciones Fabry-Perot
La interacción de galaxias es un fenómeno común en el Universo. Los efectos que tienen este tipo de encuentros sobre cada galaxia van desde la formación y/o supresión de estructura, la inducción de episodios de formación estelar y eventual actividad nuclear, hasta la transformación del tipo morfológico de las mismas. A través del estudio de su cinemática, la interacción entre galaxias nos da además la oportunidad de estudiar características como...
I. Fuentes Carrera
14/03/2003 - 13:00
Stellar population synthesis as an inverse problem. Application to nearby galaxies.
The problem of ``stellar population synthesis'' is to derive the stellar population of an unresolved stellar system using a database of stars or clusters. In this talk I will set out the two different approaches adopted since the 60s in order to solve this problem and will discuss the connected drawbacks. Then I will expose an inverse stellar population synthesis method that I developped with Didier Pelat from the ``Observatoire de Meudon'' (...
J. Moultaka
10/03/2003 - 13:00
Metallicity in Photon Dominated Regions
Dense molecular ISM is the site of star formation. FUV radiation from hot stars heat the nearby molecular gas establishing a region called Photon Dominated Regions (PDRs), where the physical and the chemical processes are dominated by the FUV field. The UV radiation not only heats the molecular gas but also regulates the star formation process itself. In low metallicity systems, such as LMC, SMC and dwarf galaxies, a reduced number of dust...
S. Jekayumar
10/02/2003 - 13:00
El papel de los archivos en la investigación astronómica
Aunque durante mucho tiempo no ha sido así, hoy se encuentra ampliamente aceptado el hecho de que los archivos juegan un papel fundamental en la investigación astronómica. Basta mirar las estadísticas de uso de archivos de misiones como HST para darse cuenta de que este hecho es una realidad innnegable. El objetivo de esta presentación es el de, tras una breve introducción histórica de los archivos en Astronomía, definir de forma precisa qué se...
Enrique Solano
06/02/2003 - 13:00
Peculiar Star Complexes
Tbd  
Yuri Efremov
24/01/2003 - 13:30
A new H alpha survey of star formation in field spiral and irregular galaxies
I will discuss results from the recently-completed H-alpha Galaxy Survey (HaGS), which resulted in H alpha and broad-band R imaging of 334 star-forming galaxies out to 3000 km/s, selected as an unbiassed subset of the Uppsala Galaxy Catalogue. Initial results from this survey include measuring the type dependence of star formation activity, determination of the effect of the group environment on star formation, normalised to activity in isolated...
Phil James
24/01/2003 - 13:00
H-alpha survey of low-redshift cluster galaxies: Contributions to an understanding of cluster galaxy evolution
Results of an extensive H alpha survey of 8 low-redshift clusters to compare cluster and field galaxy star formation will be reviewed. It will be shown how these results indicate the importance of tidal interactions on in-falling spiral galaxies for the evolution of the cluster disk galaxy population.  
Chris Moss
15/01/2003 - 13:00
IMaX: un magnetógrafo para SUNRISE
El globo estratosférico antártico SUNRISE es una colaboración entre Alemania, Estados Unidos y España y llevará a bordo un telescopio solar de nueva tecnología de C/Si C (el primario tiene 1 m de abertura y tan sólo 60 kg de peso). El telescopio lleva tres instrumentos posfocales principales: un espectropolarímetro, una cámara con un filtro universal birrefringente y un magnetógrafo. El magnetógrafo IMaX es enteramente español y basado en...
José Carlos del Toro Iniesta
26/11/2002 - 13:00
Presente y Futuro de la Relatividad General
Se revisan aspectos fundamentales de la Relatividad General y de sus aplicaciones, prestando un énfasis especial a los problemas cosmológicos actuales tanto teóricos como observacionales y, sobre todo, a la astrofísica de altas energías, en particular a aspectos presentes y futuros relativos a agujeros negros y ondas gravitatorias. El objetivo esencial de esta charla es poner de manifiesto el excelente estado de salud del que goza la relatividad...
Pedro González
20/11/2002 - 13:00
Supervientos Galácticos
Tbd  
Guillermo Tenorio Tagle
11/11/2002 - 13:00
A Cosserat Detector for Dynamic Geometry
It is proposed to explore the interaction of weak gravitational fields with slender elastic materials in order to assess the viability of achieving enhanced laser interferometric sensitivities for the detection of gravitational waves with frequencies between 1e-4 and 1 Hz. The aim is the design of novel gravitational antennae in interplanetary orbit. The implementation of these ideas would be complimentary to existing programmes of gravitational...
Robin Tucker
07/11/2002 - 13:00
Molecular outflows in high-mass star-forming regions: the extreme case of IRAS 20126+4104
As part of an outflow study in high-mass star-forming regions we observed the outflow in 20126+4104. It molecular outflow shows extremely high-velocity gas that extends in velocity more than +/- 50 km/s from the LSR. Comparing the different velocity components with the previously observed SiO jet, we found different orientation between the jet and the outflow that we interpret due to a precessing jet. The energetic of the outflow and it effects...
Mayra Lebron
09/10/2002 - 14:00
The Legacy of the HST for Studies of Stellar Populations in the Local Group
Over the past 10 years, most of the galaxies in the Local Group have been observed by the HST for the purpose of studying their stellar populations. I will present a summary of some of these observations, and describe some of the key scientific questions that have been addressed with these data. I will focus on the issue of derived star formation histories of Local Group galaxies, giving my perspective of the important issues, some of the...
Prof. Jon Holtzman
04/10/2002 - 14:30
Modelization of the giant HII regions NGC588 and NGC595
Tbd  
Luc Jamet
04/10/2002 - 14:00
Investigating the Starburst-AGN connection
Tbd  
Lucimara Martins
03/10/2002 - 14:00
The evolution of stars and gas in Starburst galaxies
Tbd  
Roberto Cid Fernandes
01/10/2002 - 14:00
Mass accretion to supermassive blackholes in the nuclei of galaxies
Tbd  
Thaisa Storchi-Bergmann
30/09/2002 - 14:00
Jet directions in AGNs
Tbd  
Henrique Schmit
26/09/2002 - 14:00
Afterglows of gamma-ray bursts
Ever since the first fading counterpart of Gamma Ray Burst (GRB) was discovered in 1997 there had been tremendous progress in our understanding of GRBs both in observation and theory. In this talk I will summarize the various aspects we learnt from multi-band observations of GRBs as well as the open issues. I will mention the contribution fron Indian observatories and particularly the observations I carried out at Vainu.  
S.G. Bhargavi
15/07/2002 - 14:00
The feeding of monsters - a study of nearby active galaxies
The understanding of the nature of AGNs and the galaxies hosting them belongs to one of the most interesting topics of modern astrophysical research. Especially the fueling mechanisms of the central black hole - supposed to be responsible for the enormous activity in these objects - raise a wealth of unanswered questions. The so called NUGA (NUclei of GAlaxies) survey an international collaboration and the Cologne Nearby QSO sample aim at...
Melanie Krips
03/07/2002 - 14:00
Luminous Vs. dark matter in the inner parts of bright spiral galaxies
The inner part of the rotation curve is crucial in determining the nature of the dark matter. The shape of the dark spherical halo is determined by the central density and the core radius. Haloes built up by hierarchical merging in dark matter cosmogonies are cusped and dominated by dark matter at the very centre. These characteristics seem to disagree with a number of observations. The number of subhaloes around typical galaxies, as identified...
Isabel Pérez
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
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
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

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