Seminaris / Seminarios / Seminars





Titulo/Titol/Title ALFALFA: the Search for Low Mass Halos in the Local Universe
Conferenciant/Conferenciante/Speaker Dr. Martha Haynes
Institucio/Institucion/Institution Cornell University, NY, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
Dimecres, 13 d'octubre de 2004
A les 12:45h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jm.solanes@ub.edu
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Titulo/Titol/Title The Cornell-Caltech Far Infrared/Submm Atacama Telescope Project
Conferenciant/Conferenciante/Speaker Dr. Riccardo Giovanelli
Institucio/Institucion/Institution Cornell University, NY, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula Planta 5a. Facultat Física
Dimecres, 14 d'octubre de 2004
A les 11:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jm.solanes@ub.edu
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Titulo/Titol/Title Identification of gamma-ray sources in the multi-messenger era: some ideas
Conferenciant/Conferenciante/Speaker Dr. Diego F. Torres
Institucio/Institucion/Institution Lawrence Livermore National Laboratory
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus. Facultat Física
Dilluns, 8 de novembre de 2004
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jm.solanes@ub.edu
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Titulo/Titol/Title High-energy emission of hadronic origin from microquasars
Conferenciant/Conferenciante/Speaker Dr. Gustavo E. Romero
Institucio/Institucion/Institution Instituto Argentino de Radioastronomia, IAR
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus. Facultat Física
Dimarts, 16 de novembre de 2004
A les 16:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jm.solanes@ub.edu
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Titulo/Titol/Title METHANOL MASERS AS TOOLS FOR STUDYING STAR FORMATION
Conferenciant/Conferenciante/Speaker Dr. MICHELE PESTALOZZI
Institucio/Institucion/Institution ONSALA SPACE OBSERVATORY (SUECIA)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
Dimarts, 23 de novembre de 2004
A les 16.00h
Resum/Resumen/Abstract

Using a consistent survey of the galactic plane at 6.7 GHz as a starting point, this talk reports on the observational as well as theoretical results achieved by extensively studying of the phenomenon of class II methanol masers. The talk will be divided in two parts, the first presenting the General Catalog of 6.7GHz methanol masers, the second reporting the successful modelling of a northern source (NGC7538 IRS 1 N) as a keplerian rotating disc.


Contacte/Contacto/Contact cesca@am.ub.es
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Titulo/Titol/Title The entrainment process of carbon dioxide in the atmospheric boundary layer
Conferenciant/Conferenciante/Speaker Dr. Jordi Vilà-Guerau de Arellano
Institucio/Institucion/Institution Meteorology and Air Quality Section, Wageningen University. The Netherlands
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 321
13 de desembre de 2004
A les 12:45h
Resum/Resumen/Abstract



Contacte/Contacto/Contact rosa@am.ub.es
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Titulo/Titol/Title Boundary Layer Mixing by Buoyant Cumulus Clouds
Conferenciant/Conferenciante/Speaker Dr.John Young
Institucio/Institucion/Institution University of Wisconsin-Madison, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 321
20 de desembre de 2004
A les 12:45h
Resum/Resumen/Abstract



Contacte/Contacto/Contact rosa@am.ub.es
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Titulo/Titol/Title Modulating X-Ray Iron Line Emission in the Seyfert Galaxy NGC3516: Relativistic Effects and Implications for the Black Hole Mass
Conferenciant/Conferenciante/Speaker Dr. Kazushi Iwasawa
Institucio/Institucion/Institution Institute of Astronomy, University of Cambridge, UK
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505 (Planta 5a)
14 de gener de 2005
A les 12:00h
Resum/Resumen/Abstract

I will present our finding of systematic, energy and flux variations of a transient, redshifted iron line emission in the Seyfert galaxy NGC3516 observed with XMM-Newton. The spectral evolution can be interpreted as a result of orbital motion of an illuminated spot on the accretion disk in the relativistic region around a black hole, which causes modulating relativistic effects on the line emission. Combining the orbital timescale and radius, inferred from the observed line variations, would yield an estimate of the black hole mass, which is in agreement with values obtained from other techniques.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title Un nou model de quasars: col.lisions d'estrelles amb el disc d'acreció
Conferenciant/Conferenciante/Speaker Dr. Jordi Miralda
Institucio/Institucion/Institution IEEC (Fundació Catalana per a la Recerca)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
8 de febrer de 2005
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact eduard@am.ub.es
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Titulo/Titol/Title Binarias de rayos X, estrellas Be y blue stragglers en cúmulos abiertos jóvenes
Conferenciant/Conferenciante/Speaker Dr. Ignacio Negueruela
Institucio/Institucion/Institution Universitat d'Alacant
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
16 de febrer de 2005
A les 12:00h
Resum/Resumen/Abstract

La mayor parte de los cúmulos abiertos jóvenes contienen importantes poblaciones de estrellas blue straggler, que aparentan ser más jóvenes que el resto del cúmulo. Las razones de la presencia de estas blue stragglers no se conocen con certeza, y podrían ser múltiples, pero resulta curioso observar que en muchos cúmulos con edades en el rango 50-150 Myr una fracción importante de las blue stragglers son estrellas Be. Presentaré los resultados de una serie de campañas de observación destinadas a determinar la fracción de estrellas Be en cúmulos abiertos y discutiré la posibilidad de que una parte de las blue stragglers se formen como consecuencia de la transferencia de masa en una binaria interactiva. En algunos casos, por lo menos, esta posibilidad se revela cierta por la presencia de binarias de rayos X entre las blue stragglers.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title El medio interestelar alrededor de la asociación de Sco-Cen
Conferenciant/Conferenciante/Speaker Dr. Wolfgang Poppel
Institucio/Institucion/Institution Instituto Argentino de Radioastronomía
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
17 de febrer de 2005
A les 12:00h
Resum/Resumen/Abstract

Se combinó el relevamiento de alta sensibilidad en línea de 21 cm del cielo austral hecho en el Instituto Argentino de Radioastronomía con su similar del cielo norte hecho en Dwingeloo (Hartmann & Burton, 1997), a fin de hacer un estudio de las peculiaridades que presenta el medio interestelar en una amplia zona alrededor de la asociación estelar de Sco-Cen. Dichas peculiaridades son morfológicas (loops y arcos alrededor de la asociación) y cinemáticas (velocidades radiales LSR de acercamiento y de alejamiento, en algunos casos de hasta algunas decenas de km/s), y se las describe mediante mapas. Se muestra que existe una relación global entre los mapas cinemáticos de la intensidad de radiación H I (curvas de nivel latitud-velocidad radial para valores de longitud constante) y los mapas de 3D para idénticas longitudes, computados por Vergely et al. (2001) para el Na I interestelar a partir de observaciones ópticas en absorción en espectros estelares. Independientemente, se derivan límites superiores para las distancias de varios de los objetos de H I. La conclusión es que el material interestelar alrededor de la asociación de Sco-Cen forma parte del anillo de gas en expansión característico del Cinturón de Gould y que la asociación presumiblemente se formó en dicho gas. La masa total del gas vinculado a la asociación se estima en 312000 masas solares, suponiendo una distancia media del H I de 100 pc, una masa molecular de 35000 masas solares y un 30 % de He. Se modelan sendas cáscaras de H I en expansión alrededor de cada uno de los tres subgrupos de la asociación. Si bien los modelos son muy simplificados (isotropía y homogeneidad del medio), ellos permiten algunas conclusiones consistentes con las observaciones, como ser: existencia de interacciones entre las cáscaras, casquetes de gas en acercamiento, velocidades peculiares, perturbaciones del gas local. Finalmente, se considera un escenario adecuado para la formación de la asociación, proponiéndose que sea en el contexto de un origen explosivo del anillo de gas en expansión observado asociado al Cinturón de Gould.


Contacte/Contacto/Contact cesca@am.ub.es
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Titulo/Titol/Title Is there any dark matter in the Galaxy?
Conferenciant/Conferenciante/Speaker Dr. Benoit Famaey
Institucio/Institucion/Institution Oxford University - Universite Libre de Bruxelles
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus
22 de febrer de 2005
A les 12:00h
Resum/Resumen/Abstract

I will review the "evidence" for dark matter in external galaxies, and point out the inherent problems of the dark matter paradigm. I will then present the results of a recent dynamical model of the Milky Way that sucessfully accounts for many different probes of the Galaxy's mass distribution interior to the Sun with a negligible amount of dark matter. The dark matter halo of this model disagrees with predictions of the standard cold dark matter cosmology, but agrees exactly with the correction to the law of gravity predicted by Modified Newtonian Dynamics (MOND) under the assumption that there is no dark halo.


Contacte/Contacto/Contact xluri@am.ub.es
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Titulo/Titol/Title Bayesian Extrasolar Planet Detection
Conferenciant/Conferenciante/Speaker Prof. Phil Gregory
Institucio/Institucion/Institution Univ. of British Columbia, Canada
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de seminaris. Dept. d'Astronomia i Meteorologia. Planta 7a
Dimecres, 27 d'Abril de 2005
A les 12:00h
Resum/Resumen/Abstract

Seminari informal de discussió amb gent interessada en el tema


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title A Bayesian Revolution in Spectral Analysis
Conferenciant/Conferenciante/Speaker Prof. Phil Gregory
Institucio/Institucion/Institution Univ. of British Columbia, Canada
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de seminaris. Dept. d'Astronomia i Meteorologia. Planta 7a
Dijous, 28 d'Abril de 2005
A les 12:00h
Resum/Resumen/Abstract

Increasingly, researchers in many branches of science are coming into contact with Bayesian statistics or Bayesian probability theory. By encompassing both inductive and deductive logic, Bayesian analysis can improve model parameter estimates by many orders of magnitude. It provides a simple and unified approach to all data analysis problems, allowing the experimenter to assign probabilities to competing hypotheses of interest, on the basis of the current state of knowledge.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title A Coupled Accretion-Jet Model for Microquasars
Conferenciant/Conferenciante/Speaker Dr. Wei Cui
Institucio/Institucion/Institution Department of Physics. Purdue University. USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505 - Planta 5. Facultat de Física
Dimarts, 31 de Maig de 2005
A les 12:00h
Resum/Resumen/Abstract

Since microquasars are X-ray binaries, the studies of them have historically been focused on the X-ray emission. While the X-ray light curves of these sources can be messy and complicated, their spectral energy distributions (SEDs) seem to be much simpler. In gross terms, there are two varieties: the SED peaks either at around 1 keV or 100 keV, corresponding to soft X-ray or hard X-ray dominated states; Of course, the SED takes on an intermediate form as a source goes from one state to the other. It is generally thought that the emission from microquasars is powered by mass accretion. However, it has become increasingly clear, from radio observations, that the role of jets should not be ignored, particularly in the hard state. To quantify the role accurately, broadband SEDs are required. In this talk, a coupled accretion-jet model will be presented to account for the spectral energy distribution of microquasars. The application to XTE J1118+480 (which has the best SED among all microquasars) demonstrates the viability of the model. The results will be presented and the predictions of the model described.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title On the Origin of the X-ray Structure in the Center of Crab Nebula
Conferenciant/Conferenciante/Speaker Dr. Dmitri Khangulyan
Institucio/Institucion/Institution Max Planck Institut fur Kernphysik (Heidelberg, Germany)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 9 de Juny de 2005
A les 12:00h
Resum/Resumen/Abstract

We have investigated on the origin of the X-ray structure in center part of Crab Nebula in the framework of Kennel & Coroniti theory. A simple analytical model following a MHD approach will be presented to explain the formation of the torus- and jet-like features in plerions.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title A Wavelet Approach for the Study of Intra-group Light in Hickson Compact Groups
Conferenciant/Conferenciante/Speaker Dr. Cristiano da Rocha
Institucio/Institucion/Institution Universitäts-Sternwarte Göttingen, Germany
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 14 de Juny de 2005
A les 13:00h
Resum/Resumen/Abstract

The diffuse intra-group light component observed in compact groups of galaxies represent an efficient tool for the determination of the stage of dynamical evolution of such structures and for mapping the gravitational potential of the group. This component is presumably due to stellar material tidally stripped from the member galaxies of the group, which gets trapped in the group potential. The detection of this kind of low surface brightness structure (about 1% above the sky level) is subject to many effects, as stars and galaxy modeling and sky subtraction. We are applying a new method, the wavelet technique OV\_WAV, with which these low surface brightness structures can be revealed and analyzed by separating different components according to their spatial characteristic sizes (allowing the study of the point sources, galaxies and diffuse envelope separately). We have analyzed a subsample of the Hickson Compact Groups Catalogue (HCG 79, HCG 88 and HCG 95), and the diffuse component was in two of the studied groups: HCG 79, where it corresponds to 46% of the total $B$ band light and HCG 95, where the fraction is 11%. HCG 88 had no component detected, as expected by its estimated evolutionary stage. Those structures have a mean $B$ band surface brightness of $24.8\pm0.18$ and $27.3\pm0.18$, for HCG 79 and HCG 95, respectively.


Contacte/Contacto/Contact eduard@am.ub.es
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Titulo/Titol/Title Rotating Disks in High-Mass Young Stellar Objects: G24.78+0.08 and G31.41+0.31
Conferenciant/Conferenciante/Speaker Dra. Maite Beltrán
Institucio/Institucion/Institution Dept. Astronomia i Meteorologia, Univ. de Barcelona
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dimecres, 6 de Juliol de 2005
A les 12:00h
Resum/Resumen/Abstract

I will discuss the detection of four rotating massive disks in two regions of high-mass star formation. The disks are perpendicular to known bipolar outflows and turn out to be unstable but long lived. We infer that accretion onto the embedded (proto)stars must proceed through the disks with rates of ~0.01 Msolar/yr.


Contacte/Contacto/Contact robert.estalella@am.ub.es
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Titulo/Titol/Title Research on Hurricane Katrina and her Cousins
Conferenciant/Conferenciante/Speaker Prof. Brian Mapes
Institucio/Institucion/Institution University of Miami - RSMAS, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Divendres, 30 de Setembre de 2005
A les 13:00h
Resum/Resumen/Abstract

Hurricane research is divided into questions of formation, motion, and intensity. Intensity change was studied in a large experiment based at UM this year. Three coordinated aircraft with Doppler radars flew in Katrina and other storms.


Contacte/Contacto/Contact ileanablade@ub.edu
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Titulo/Titol/Title Magnetismo solar, pingüinos y Solar Orbiter
Conferenciant/Conferenciante/Speaker Dr. Valentín Martínez-Pillet
Institucio/Institucion/Institution Instituto de Astrofísica de Canarias
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 10 de Novembre de 2005
A les 10:30h
Resum/Resumen/Abstract

Mesures locals del camp magnetic solar a partir d'observacions en llum polaritzada. Experiment IMAX (globus estratosfèric)a l'Antartida. La missió al Sol, Solar Orbiter (SolO, Agencia Espacial Europea)i VIM/SolO, un magnetómetre vectorial de filtres polaritzants liquids.


Contacte/Contacto/Contact Blai.Sanahuja@ub.edu
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Titulo/Titol/Title Hadronic high-energy gamma-ray emission from massive microquasars
Conferenciant/Conferenciante/Speaker Mariana Orellana
Institucio/Institucion/Institution Instituto Argentino de Radioastronomía, IAR
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dimarts, 15 de Novembre de 2005
A les 12:00h
Resum/Resumen/Abstract

Accreting X-ray binary systems that eject collimated relativistic outflows or jets are called microquasars. Recently microquasars had been confirmed to be high energy gamma-ray sources, though the origin of this high energy emission is still debated. We present a hadronic model for gamma-ray production in windy microquasars, with a particular application on LS I +61 303. This system is formed by a neutron star that accretes matter from the dense and slow equatorial wind of the Be primary star. We calculate the gamma-ray emission originated in pp interactions between relativistic protons in the jet and cold protons from the wind. After taking into account opacity effects on the gamma-rays introduced by the different photons fields, we present high-energy spectral predictions that can be tested with the new generation Cherenkov telescope MAGIC. A final paragraph is devoted to the neutrino emission that is produced together with the photon signal.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title Broadband emission from high energy processes in microquasars
Conferenciant/Conferenciante/Speaker Valentí Bosch-Ramon
Institucio/Institucion/Institution Universitat de Barcelona
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Divendres, 2 de Desembre de 2005
A les 12:00h
Resum/Resumen/Abstract

Microquasars are X-ray binaries that present relativistic radio jets. The high energy processes that take place in microquasars are of great importance to understand the spectral and time properties of the observed emission from these sources. We have considered the main elements of the microquasar scenario, altogether with their intrinsic and relational properties, studying afterward what observational features come out. Our aim has been to build physically meaningful models following a comprehensive approach, well in agreement with the phenomenology and capable of providing predictions concerning the physics underlying not only radiative processes, but also globally other important aspects of microquasars and their environment.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title PARTNeR: una observación radioastronómica en directo
Conferenciant/Conferenciante/Speaker Dra. Olga Suárez Fernández
Institucio/Institucion/Institution LAEFF-INTA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 15 de Desembre de 2005
A les 10:30h
Resum/Resumen/Abstract

PARTNeR es un programa educativo dedicado a que los estudiantes de educación secundaria y de universidad realicen observaciones radioastronómicas remotas con una de las antenas de 34 m de la estación espacial de Robledo de Chavela. El objetivo del programa es que los estudiantes tengan una experiencia científica real que les sirva para acercarse a la ciencia de una manera más amable, y que les permita tomar datos que puedan ser de utilidad científica. Durante la charla se realizará una breve observación en directo con la antena de PARTNeR.


Contacte/Contacto/Contact jmparedes@ub.edu
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Titulo/Titol/Title Coronal Mass Ejection initiation and evolution simulations at CPA
Conferenciant/Conferenciante/Speaker Dr. Stefaan Poedts
Institucio/Institucion/Institution Centre for Plasma Astrohysics, K.U. Leuven -Bélgica
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dimarts, 21 de Febrer de 2006
A les 12:00h
Resum/Resumen/Abstract

Dr. Poedts' research is situated in the field of computation and nonlinear magnetohidrodynamics with applications in "solar astrophysics". He is particularly interested in MHD wave dynamics (generation, propagation, and dissipation) of coronal loops, coronal holes, galactic and extra-galactic jets, and accretion disks and in the nonlinear dynamics of Coronal Mass Ejections and super-fast magnetized flows around comets, moons, and planets and the MHD shock interactions in such flows (related to space weather).


Contacte/Contacto/Contact blai@am.ub.es (Blai Sanahuja)
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Titulo/Titol/Title Simulaciones climáticas del último milenio
Conferenciant/Conferenciante/Speaker Dr. Jesús Fidel González Rouco
Institucio/Institucion/Institution Dpto. Astrofisica y CC. de la Atmósfera, Universidad Complutense de Madrid
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dimecres, 22 de Febrer de 2006
A les 11:00h
Resum/Resumen/Abstract

El aumento de temperatura global a lo largo de las últimas décadas y su posible origen antrópico plantea la necesidad de entender el clima actual en el contexto de la variabilidad climática a lo largo del último milénio. Los avances en este campo se han fundamentado en la simulación paleoclimática con modelos globales de atmósfera y océano y en la reconstrucción climática a partir de fuentes de información indirecta (proxy).


Contacte/Contacto/Contact ileanablade@ub.edu (Ileana Bladé)
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Titulo/Titol/Title Què, quan i com observar durant els eclipsis de Sol
Conferenciant/Conferenciante/Speaker Dr. Eduard Masana
Institucio/Institucion/Institution Dpt. d'Astronomia i Meteorologia (UB)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus Eduard Fontserè (edifici nou)
Dimecres, 1 de Març de 2006
A les 16:00h
Resum/Resumen/Abstract

El proper 29 de març es produeix un eclipsi total de Sol visible a una estreta franja de terra que comença al Brasil, travessa el desert del Sàhara, Turquia i l'Àsia central i finalitza a Mongòlia. En aquest seminari es descriuran els diferents fenomens que es poden observar durant un eclipsi total de Sol. El seminari està especialment adreçat a aquelles persones que tenen intenció de desplaçar-se per observar aquest esdeveniment astronòmic.


Contacte/Contacto/Contact emasana@am.ub.es (Eduard Masana)
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Titulo/Titol/Title The global signal of ENSO in observations and model calculations
Conferenciant/Conferenciante/Speaker Dr. Rolando García
Institucio/Institucion/Institution National Center for Atmospheric Research, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus Eduard Fontserè (edifici nou)
Dilluns, 3 d'Abril de 2006
A les 11:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jlorentec@ub.edu (Jeroni Lorente)
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Titulo/Titol/Title Constraining Inverse Curvature Gravity with Supernovae
Conferenciant/Conferenciante/Speaker Dr. Jochen Weller
Institucio/Institucion/Institution University College London, UK
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus de la Facultat de Física (Sala de Graus Antiga)
Divendres, 21 d'Abril de 2006
A les 16:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact pilar@am.ub.es (Pilar Ruiz-Lapuente)
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Titulo/Titol/Title Star Formation in the Vela Molecular Ridge:from Molecular Clouds to Young Embedded Clusters
Conferenciant/Conferenciante/Speaker Dr. Fabrizio Massi
Institucio/Institucion/Institution Osservatorio Astrofisico di Arcetri (Florencia)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dimecres, 24 de Maig de 2006
A les 11:00h
Resum/Resumen/Abstract

The Vela Molecular Ridge (VMR) is a giant molecular cloud complex located within the galactic plane, in the outer galaxy. It is one of the nearest regions (d ~ 700 pc) hosting massive star formation. One of its molecular cloud, named VMR-D, exhibits a large efficiency in producing small young embedded clusters. I will present large scale maps (1x1 deg) of the cloud at mm wavelengths, both line (CO) and continuum (1.2 mm), with unprecedented resolution. Then, I will present near-IR images of a sample of associated young embedded clusters. A picture of the star formation history emerges, from large to small scale, that will be briefely discussed.


Contacte/Contacto/Contact mbeltran@am.ub.es (Maite Beltran)
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Titulo/Titol/Title Damped Lyman-alpha systems and Lyman break galaxies
Conferenciant/Conferenciante/Speaker Dr. Chenggang Shu
Institucio/Institucion/Institution Joint Center for Astrophysics. Shanghai Normal University. China
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 25 de Maig de 2006
A les 12:00h
Resum/Resumen/Abstract

DLAs and LBGs are very important to understand galaxy formation and evolution at high redshift (z~3). The observational properties of DLAs and LBGs are briefly summarized. Semi-analytic models are applied to these two populations at z~3 including their host galaxies, metallicticity distribution, size distribution, galactic winds and mass outflows, and clustering etc as well.


Contacte/Contacto/Contact carme@am.ub.es (Carme Jordi)
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Titulo/Titol/Title Computers and supercomputers: our laboratories for understanding galaxies
Conferenciant/Conferenciante/Speaker Prof. Evangelie Athanassoula
Institucio/Institucion/Institution Observatoire Astronomique de Marseille Provence. France
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari Planta 7a. Facultat de Física
Dijous, 1 de Juny de 2006
A les 11:00h
Resum/Resumen/Abstract

Galaxies are complex objects composed of stars, gas clouds and dark matter. The latter can not be observed directly, but it exerts a gravitational force on the stars and on the gas clouds. Seen the complexity of galaxies, the scope of analytical work on them is very limited. But we are lucky enough to live at a time where computers are sufficiently powerful to allow us to follow the dynamical evolution of galaxies and to understand how their components and substructures are formed and how they evolve. In this lecture I will discuss how computer experiments can be set up and analysed and how computers can be used to increase our knowledge on galaxies. In particular, I will discuss the evolution of disc galaxies and the formation of bars. Movies from simulations will be used to illustrate these processes, as well as the interactions between galaxies.


Contacte/Contacto/Contact jm.solanes@ub.edu (Josep Maria Solanes)
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Titulo/Titol/Title Cepheus A, an ideal laboratory for testing and opening new theories on high-mass star formation
Conferenciant/Conferenciante/Speaker Dr. José María Torrelles
Institucio/Institucion/Institution ICE(CSIC)--IEEC(UB,CSIC,UPC,UAB,FCR,DURSI)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula-Seminari 505. Planta 5a. Facultat de Física
Dijous,8 de Juny de 2006
A les 12:00h
Resum/Resumen/Abstract

Cepheus A is one of the closest high-mass star-forming regions. At the center of a high-density molecular core, within a 20 arcsec (15000 AU) radius region, there is a cluster of 16 compact radio continuum sources, some of them associated with phenomena such as Herbig-Haro objects, molecular outflows, jets, disks, masers, and strong magnetic fields, all of which are signatures of the first steps of evolution of young stars. In this talk I will review some of the past and most recent observations that have made of Cepheus A an ideal laboratory for testing and opening new puzzling questions related to the early stellar evolution.


Contacte/Contacto/Contact torrelles@ieec.fcr.es (José María Torrelles)
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Titulo/Titol/Title ASTROSAT: An Indian Multi wavelength Astronomy Satellite
Conferenciant/Conferenciante/Speaker Dr. Ishwara Chandra C. H.
Institucio/Institucion/Institution National Center for Radio Astrophysics, TIFR, India
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dijous,20 de Setembre de 2007
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Formación estelar masiva
Conferenciant/Conferenciante/Speaker Dr. Luis Felipe Rodríguez
Institucio/Institucion/Institution Centro de Radioastronomía y Astrofisica. UNAM, Morelia (México)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimarts,9 d'Octubre de 2007
A les 12:00h
Resum/Resumen/Abstract

En las últimas décadas se ha consolidado un esquema que describe de manera adecuada la formación de las estrellas de tipo solar. ¿Podemos extender este esquema a la formación de las estrellas de alta masa? Este es un tema de investigación que ha generado gran interés y revisaremos la evidencia encontrada en una lista selecta de estrellas masivas en formación.


Contacte/Contacto/Contact torrelles@ieec.fcr.es (José María Torrelles)
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Titulo/Titol/Title Massive Star and Gamma-Rays
Conferenciant/Conferenciante/Speaker Dr. Gustavo E. Romero
Institucio/Institucion/Institution Instituto Argentino de Radioastronomía, IAR
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimarts,23 d'Octubre de 2007
A les 12:00h
Resum/Resumen/Abstract

The production of gamma-rays in astrophysical settings is usually associated with exotic objects like black holes, pulsars, and AGNs. In this talk it will be shown that even the most traditional astronomical objetcs, the stars, can generate gamma-rays under a variety of circumstances. It will be described how massive proto-stars, isolated hot stars, massive binary stars, and stellar associations can generate detectable gamma-ray emission, opening a new window for stellar studies.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title RCW 108 i la formació estel.lar induida
Conferenciant/Conferenciante/Speaker Dr. Fernando Comerón
Institucio/Institucion/Institution European Southern Observatory, ESO
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimecres,31 d'Octubre de 2007
A les 12:00h
Resum/Resumen/Abstract

RCW 108 és una regió de formació estel.lar a l'associació Ara OB1, consistent en un núvol molecular que està en proces de destrucció per part de la radiació ultraviolada de les estrelles massives d'un cumul vei. A l'interior d'aquest núvol hi ha un cúmul compacte molt jove que també conté estrelles massives. Presentarem noves observacions obtingudes amb òptica adaptativa amb el Very Large Telescope que permeten examinar el contingut d'aquest cúmul, i que mostren una manca accentuada d'estrelles de baixa massa en comparació amb el que caldria esperar a partir del nombre d'estrelles de massa més gran. Aquests resultats semblen confirmar que, tal com prediuen qualitativament els models, la formació estel.lar induida externament tendeix a donar com a resultat un espectre de masses que difereix significativament de la funció inicial de masses del camp i de la majoria dels cúmuls. RCW 108 apareix d'aquesta manera com un exemple molt probable de formació estel.lar induida externament, i que presenta l'important avantatge de que la majoria de les condicions de contorn poden determinar-se directament a partir de les observacions.


Contacte/Contacto/Contact cesca@am.ub.es (Francesca Figueras)
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Titulo/Titol/Title Non-thermal radiation from massive star/jet systems (single or double)
Conferenciant/Conferenciante/Speaker Dr. Valentí Bosch Ramon
Institucio/Institucion/Institution Max Planck Institut fur Kernphysik, Heidelberg
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dilluns, 5 de Novembre de 2007
A les 12:00h
Resum/Resumen/Abstract

Massive stars enbed their environments with dense radiation and matter fields. When accretion takes place, the formation of supersonic powerful outflows is likely. Such outflows and their environment, whose properties depend strongly on the star, can interact producing significant multiwavelength radiation via thermal and non thermal processes. We will focus here on the latter.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Simulations and Experiments of Stellar Jets
Conferenciant/Conferenciante/Speaker Dr. Andrea Ciardi
Institucio/Institucion/Institution Observatoire de Paris, (LERMA) and Imperial College, Plasma Physics Group, London
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimarts, 6 de Novembre de 2007
A les 12:00h
Resum/Resumen/Abstract

In recent years the development of high-energy density plasma experiments has opened the way to the study of extreme astrophysical phenomena in the laboratory. The validity of the laboratory studies rests, partly, on the condition that the important dimensionless numbers (Reynolds, Peclet, etc) are in the same range as those in the astrophysical environment. Coupled with numerical modelling, much understanding can then be gained by analysing the resulting laboratory phenomena.

Pulsed-power facilities are generally dedicated to the study of intense X-ray sources and high-energy density plasmas with applications to inertial confinement fusion. I will first present a brief review of the development of jet experiments on such facilities and then discuss recent work on (magneto)hydrodynamic jets. In particular I will present experiments addressing the dynamics of curved stellar jets, observed in many star forming regions, and new results to study magnetically launched jets. The implications and relevance to astrophysical models, and future laboratory modelling will be addressed.


Contacte/Contacto/Contact rosario@am.ub.es (Rosario López)
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Titulo/Titol/Title Some inferences about the bulk speed of the AGN jets
Conferenciant/Conferenciante/Speaker Dr. Gopal Krishna
Institucio/Institucion/Institution NCRA.TIFR, Pune, India
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dijous, 22 de Novembre de 2007
A les 12:00h
Resum/Resumen/Abstract

Jets of nonthermal radiation are the most conspicuous manifestations of the active galactic nuclei (AGN). In recent years, bulk speeds of the radiating plasma in the jets have been estimated in multiple ways and often these estimates have turned out to be widely discrepant. A similar uncertainty exists about the deceleration scenarios for the powerful blazar jets. These aspects will be reviewed and a possiblity to reconcile these conflicting estimates will be discussed.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title The CIRCE Infrared Camera for the Gran Telescopio Canarias
Conferenciant/Conferenciante/Speaker Dr. Stephen S. Eikenberry
Institucio/Institucion/Institution University of Florida
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimecres, 12 de Desembre de 2007
A les 12:00h
Resum/Resumen/Abstract

I will give a presentation of the Canarias InfraRed Camera Experiment (CIRCE) -- a visitor-class near-infrared camera and spectrograph for the Gran Telescopio Canarias which will be open for use by the GTC community near Day One. CIRCE is fundamentally a high-throughput imager with a 3.4x3.4-arcminute field of view and image quality limited by seeing down to < 0.3-arcsec. In addition, CIRCE has powerful capabilities for narrowband imaging, low-resolution spectroscopy, polarimetry, high-speed photometry/polarimetry, and even spectro-polarimetry. I will review the current status of CIRCE, and also present some of the key science planned for early operations -- particularly, high-speed IR polarimetry of microquasar systems.


Contacte/Contacto/Contact mribo@am.ub.es (Marc Ribó)
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Titulo/Titol/Title On the properties of extra-solar planets: the observational approach
Conferenciant/Conferenciante/Speaker Dr. Nuno Santos
Institucio/Institucion/Institution Centro de Astrofisica, Universidade do Porto (Portugal)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimecres, 7 de Febrer de 2008
A les 12:00h
Resum/Resumen/Abstract

Since the detection a decade ago of the planetary companion of 51 Peg, more than 200 extra-solar planets have been unveiled, mostly by radial-velocity measurements but also in a few cases by photometric transit observations or in microlensing experiments. They present a wide variety of characteristics as e.g. large masses with small orbital separations, high eccentricities, period resonances in multi-planet systems, etc. Meaningful features of the statistical distributions of orbital parameters for giant planets or of parent stellar properties have emerged. We discuss them in the context of the constraints they provide for planet-formation models, and in comparison to Neptune-mass planets in short-period orbits recently detected by radial-velocity surveys. We anticipate the detection of Neptune-mass planets in longer-period orbits and even lower-mass planets in short-period orbits, giving us new information on the mass distribution function of exoplanets. Finally, the role of radial-velocity follow-up measurements of transit candidates is emphasized.


Contacte/Contacto/Contact torrelles@ieec.fcr.es (José María Torrelles)
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Titulo/Titol/Title Neutron star steady and explosive behaviours: results and predictions on their very high energy emission
Conferenciant/Conferenciante/Speaker Dr. Nanda Rea
Institucio/Institucion/Institution University of Amsterdam, Astronomical Institute "Anton Pannekoek"
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Seminari. Planta 7a. Facultat de Física
Dimecres, 19 de Febrer de 2008
A les 12:00h
Resum/Resumen/Abstract

I will review on the state of the art of neutron star astronomy, with a particular attention on the very high energy emission discovered from a few of these systems. I will then focus on new results obtained through the spectral modeling of magnetars' multi-band emission, and thanks to a detailed study of their large variety of flaring activity. Furthermore, given these new results, I will present detailed predictions on the observability of magnetars in the MeV - TeV energy range with current and future instrumentation.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Inertial range of the turbulent cascade in the solar wind: energy flux and turbulent heating through the scales
Conferenciant/Conferenciante/Speaker Dr. Luca Sorriso-Valvo
Institucio/Institucion/Institution Università della Calabria, Italia
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dimecres, 27 de Febrer de 2008
A les 12:00h
Resum/Resumen/Abstract

Measuring the solar wind parameters is the only way to experimentally study turbulence in plasmas. Since the first spacecraft missions, it has been clear that a wide spectrum of turbulent fluctuations is present in the wind plasma. Such behaviour has been attributed to a magnetohydrodynamic (MHD) turbulence developing in the wind. In this framework, an exact law derived from the MHD equations has been recently obtained, to describe the statistical properties of the turbulent energy flux from the large scales, where it is injected in the system, toward the small scales, where it is eventually dissipated. Such law has been now observed in fast, polar wind measured by Ulysses spacecraft during low solar activity periods. This observation represents the first proof that a MHD energy cascade is indeed occurring in the solar wind turbulence. Through the data, it is also possible for the first time to directly measure the turbulent energy dissiaption rate, which can be now be compared to the non-adiabatic radial profile of the wind temperature. Such comparison shows that the energy transported from turbulence plays an important role in the local heating of the wind.


Contacte/Contacto/Contact nagueda@am.ub.es (Neus Agueda)
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Titulo/Titol/Title En busca de Maat: astronomía, paisaje y simbolismo en el Egipto antiguo
Conferenciant/Conferenciante/Speaker Dr. Juan Antonio Belmonte Avilés
Institucio/Institucion/Institution Instituto de Astrofísica de Canarias, IAC
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus Eduard Fontseré
Dijous, 28 de Febrer de 2008
A les 12:00h
Resum/Resumen/Abstract

La arqueoastronomía no ha gozado de las simpatías de la comunidad egiptológica por diversas causas. Por este motivo, cuestiones importantes como la orientación de los templos egipcios y la importancia de la astronomía a este respecto nunca han sido abordadas con la necesaria seriedad y profundidad. La misión Hispano-Egipcia de "Arqueoastronomía del Egipto Antiguo" se ha propuesto, entre otros objetivos, solventar este problema. Para ello, se ha medido la orientación de más de 330 templos en el Valle, el Delta y los Oasis, incluyendo los templos asociados a las grandes pirámides, con el fin de obtener una muestra estadísticamente significativa que nos permita responder con claridad la pregunta: ¿están orientados astronómicamente los monumentos egipcios? Nuestro datos parecen confirmar este hecho y, además, ofrecen una perspectiva muy interesante por la que, en realidad, la arqueoastronomía quedaría enmarcada como una herramienta más de una disciplina novedosa, muy interesante y poco trabajada hasta le fecha en Egipto como es la Arqueología del Paisaje, en que los paisajes terrestre, dominado por el Nilo, y celeste, dominado por el sol, la luna y las estrellas, se combinarían para permitir el establecimiento de la Ma'at, el Orden Cósmico, sobre la tierra.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Formation of bulges of disk galaxies at redshifts z~1
Conferenciant/Conferenciante/Speaker Dr. Marc Balcells Comas
Institucio/Institucion/Institution Instituto de Astrofísica de Canarias, IAC
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dimecres, 30 d'Abril de 2008
A les 12:30h
Resum/Resumen/Abstract

The reasons why many disk galaxies contain bulges, i.e. central high-density regions devoid of star formation, remain unclear. We search for clues at redshifts up to z=1.2 using high-resolution images from the Hubble Space Telescope. Up to z=0.8, for 60% of galaxies with photometric bulges, the bulges are essentially formed: they show red colours typical of passive stellar populations, and high densities. Star forming bulges show lower densities, hence bulge growth may be related to the pseudo-bulge phenomenon found in the local Universe, rather than to violent processes such as mergers. Beyond z=0.8, we find an increasing population of disks with very blue nuclei, which may correspond to intense bulge growth phase inside disks at redshifts at or above 1. That galaxies with red bulges contain older stars in both their bulges and their disks suggests that bulge formation mechanisms do not destroy the disks.


Contacte/Contacto/Contact e.salvador@ub.edu (Eduard Salvador)
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Titulo/Titol/Title Interactions between jets and clumpy stellar winds in high-mass microquasars
Conferenciant/Conferenciante/Speaker Anabella T. Araudo
Institucio/Institucion/Institution Instituto Argentino de Radioastronomía-Universidad de La Plata
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 6 de Juny de 2008
A les 12:00h
Resum/Resumen/Abstract

There is strong observational evidence pointing to the inhomogeneous nature of the winds of massive stars. In high-mass microquasars, the inhomogeneities (or clumps) of the primary star wind could interact with the jet launched from the secondary component, an accreting black hole or neutron star. The dense clumps of the wind can penetrate into the jet creating shocks and thereby accelerating particles. These relativistic particles will interact with the ambient photon, magnetic, and matter fields, generating radiation from radio to gamma-rays with a specific time signature. These broadband emission can provide information, not only on the high-energy processes occurring in microquasar jets, but also on the structure of the wind of massive stars.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Abundance anomalies in A and F stars members of open clusters
Conferenciant/Conferenciante/Speaker Dr. Marwan Gebran
Institucio/Institucion/Institution Laboratoire du GRAAL, Montpellier
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 6 de Juny de 2008
A les 10:00h
Resum/Resumen/Abstract

We observe abundance anomalies at the surface of many field and cluster A stars. These abundance anomalies are generated by microscopic diffusion acting within the stable envelopes and may be modulated by the competition between many other mixing processes such as convection, rotational mixing and mass loss. The typical patterns encountered are underabundances of Ca and/or Sc as well as overabundances of iron peek elements and rare earths. Non magnetic A stars with such patterns are classified as Am.

By observing the surface of A and F stars from open clusters in particular, we can infer additional stellar parameters such as age and initial chemical composition which are invaluable for the comparison with models. Therefore, by determining the surface composition of A and F stars from many clusters of different ages we can follow the evolution of chemical composition and constrain the processes considered in evolutionary models.

In this talk, I will present the surface abundances of 22 elements for 21 A/F stars of the Pleiades open cluster (100 Myr) and for 22 A/F stars of the Coma Berenices open cluster (450 Myr). The synthetic spectra method, which is based on ATLAS9-12 atmospheric models, is used in order to determine the abundances. These observations are then compared with evolutionary models from the Montreal group. The results show that there are hydrodynamical processes acting within the radiative zone of these stars and hindering the effects of microscopic diffusion. Keywords: spectroscopy, abundances, A stars, Am stars, F stars, radiative diffusion, open clusters: Coma Berenices, Pleiades


Contacte/Contacto/Contact carme@ub.edu (Carme Jordi)
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Titulo/Titol/Title Activitats a l'observatori ALMA a Xile
Conferenciant/Conferenciante/Speaker Dr. Pere Planesas
Institucio/Institucion/Institution Atacama Large Millimeter/submillimeter Array
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 13 de Juny de 2008
A les 12:00h
Resum/Resumen/Abstract

Es descriurà i ilustrarà l'estat actual d'ALMA a Xile. En particular, es descriuran les activitats d'ensamblatge, integració i verificació de les antenes que actualment es duen a terme al Operations Support Facility (OSF) a Atacama i a l'ALMA Test Facility (ATF) a New Mexico. Es mostrarà la situació actual de l'OSF i de l'Array Operations Site (AOS) a la vall de Chajnantor. Es descriuran les previsions d'activitats futures fins a l'inici de les operacions científiques. També es passarà revista gràfica als altres projectes actuals i futurs d'antenes submm a les valls de Chajnantor i Pampa La Bola, entre 5000 i 5600 m d'alçada.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Disc/jet coupling on all scales
Conferenciant/Conferenciante/Speaker Dr. Elmar Koerding
Institucio/Institucion/Institution University of Southampton, Regne Unit
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 4 de Juliol de 2008
A les 12:00h
Resum/Resumen/Abstract

Astrophysical jets launched from an accretion disc seem to occur in nearly all types of accreting objects: from young stellar objects to active galaxies. I will present a unified scenario for the coupled accretion disc/jet system applicable to accreting systems of all masses, power and type. The validity of the unified model will be tested with empirical connections between X-ray binaries (XRBs) and active galactic nuclei (AGN). Besides these relativistic jet sources I will extend the model to cataclysmic variables, i.e. weakly accreting white dwarfs. New evidence will be presented that these sources do show jets - unlike previous claims - and the jets behave similar to those seen in XRBs. I will conclude by applying the developed model to the problem of AGN feedback on their surrounding galaxies and clusters.


Contacte/Contacto/Contact mribo@am.ub.es (Marc Ribó)
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Titulo/Titol/Title Latest results of the COSMOSOMAS experiment
Conferenciant/Conferenciante/Speaker Dr. Sergi Hildebrandt
Institucio/Institucion/Institution Instituto de Astrofísica de Canarias, IAC
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 24 de Juliol de 2008
A les 12:00h
Resum/Resumen/Abstract

In this talk, I will present the latest results of the COSMOSOMAS experiment, a microwave telescope, placed at the Teide Observatorium in Tenerife. The results concern the Galactic physics as well as the observation of the Cosmic Background Microwave radiation. I will also expose other microwave experiments in which our group is participating.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title SASIR: The Synoptic All-Sky Infrared Imaging Survey Concept
Conferenciant/Conferenciante/Speaker Dr. Joshua S. Bloom
Institucio/Institucion/Institution Astronomy Department, University of California, Berkeley, CA, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dilluns, 22 de Setembre de 2008
A les 12:00h
Resum/Resumen/Abstract

I describe an ambitious project - a synoptic survey, of the entire night sky at infrared wavelengths to unprecedented depths using a dedicated wide-field 6.5-meter telescope in San Pedro Martir (SPM), Mexico. The concept is part of a new initiative for a ground-based telescope in partnership with Mexico and the University of California. What the Sloan Digital Sky Survey (SDSS) and Large Synoptic Survey Telescope (LSST) are to the Digitized Sky Survey (DSS), this project will be to the seminal 2 micron All-Sky Survey (2MASS). The science drivers for the synoptic all-sky infrared (SASIR) survey are numerous, from discovery of the precious and rare high-redshift QSOs in the static sky to uncovering and studying numerous obscured and red transients. We expect to have major impact on almost all topics of astronomy, from the study of low-mass stars and exoplanets to fundamental cosmology and the detection and study of transient events. I will detail the mission concept, drivers and preliminary survey plans.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title The evolution of a coronal mass ejection: what can we learn from numerical modelling?
Conferenciant/Conferenciante/Speaker Dr. Carla Jacobs
Institucio/Institucion/Institution Centrum voor Plasma-Astrofysica, K.U. Leuven (Bèlgica)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 25 de Setembre de 2008
A les 12:00h
Resum/Resumen/Abstract

Coronal Mass Ejection (CMEs) belong to the most spectacular transient events on the Sun, and are considered to be one of the main drivers of the space weather. Consequently, a careful study of these violent solar phenomena is essential for a deeper insight into space weather physics. Numerical simulations are complementary to the observations and are helpful to obtain a better understanding of the initiation, the internal structure, and the evolution of CMEs. An important common aspect of the different CME initiation scenarios currently popular, is the presence of magnetic flux rope structures, being either present before the CME lift-off takes place, or created during the eruption as a consequence of magnetic reconnections. The classic cartoon image of the three-dimensional magnetic structure of a CME propagating through the interplanetary space, is that of a magnetic flux rope with both ends nested in the Sun. In this seminar, I will present some results of our latest numerical simulations, in which we initiate a CME by a realistic trigger mechanism. The internal structure of the CME was investigated and we argue that the flux rope picture is not always the correct one.


Contacte/Contacto/Contact aaran@am.ub.es (Angels Aran)
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Titulo/Titol/Title LCDM Challenges at the Scale of Galaxies: Cosmology Meets Galactic Astronomy
Conferenciant/Conferenciante/Speaker Dr. Octavio Valenzuela
Institucio/Institucion/Institution Instituto de Astronomía de la UNAM (Mexico)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 25 de Setembre de 2008
A les 16:00h
Resum/Resumen/Abstract

A mas de 50 años de haber sido propuesta como un elemento especulativo, la hipótesis de materia oscura es capaz de explicar con éxito varios aspectos de la estructura a gran escala del Universo. Restricciones observacionales sugieren que es ocho veces mas abundante que la materia barionica y contribuye con casi un cuarto de la densidad de energía cósmica, a pesar de eso, su naturaleza y su detección son aún un reto. Durante la última década estudios observacionales a escala galáctica y subgaláctica como las curvas de rotación y la abundancia de galaxias satélites han mostrado discrepancias con las predicciones teóricas basadas en materia oscura fría, sugiriendo una posible crisis para el escenario. Dichas discrepancias han estimulado además el estudio de diferentes variantes al modelo de partículas de materia oscura fría o incluso de teorías alternativas, así como una revisión detallada de la comparación con las observaciones. En esta platica discutiré el estado actual de dicha crisis, así como resultados recientes referentes a la estructura central de las galaxias y la abundancia de subestructura.


Contacte/Contacto/Contact cesca@am.ub.es (Francesca Figueras), tantoja@am.ub.es (Teresa Antoja)
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Titulo/Titol/Title Recent results of the AGILE gamma-ray mission
Conferenciant/Conferenciante/Speaker Dr. Stefano Vercellone
Institucio/Institucion/Institution INAF/IASF-Milano
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 13 de Novembre de 2008
A les 12:00h
Resum/Resumen/Abstract

The AGILE gamma-ray mission is devoted to the study of the high-energy astrophysics phenomena. The scientific instrument is composed by three detectors: a Gamma-Ray Imaging Detector (GRID), sensitive in the 30 MeV - 50 GeV energy band, a hard X-ray monitor, Super-AGILE, sensitive in the 18-60 keV energy band, and a Mini-Calorimeter, sensitive in the energy range 300 keV - 100 MeV. During the first 18 months in orbit, AGILE detected several flaring blazars, as well as transient gamma-ray galactic sources, gamma-ray bursts, pulsars and Terrestrial gamma-ray flashes. I will review the highlights of the mission and discuss some recent results.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title A synthetic view of AGN evolution and supermassive black holes growth
Conferenciant/Conferenciante/Speaker Dr. Andrea Merloni
Institucio/Institucion/Institution Excellence Cluster Universe and MPE, Munich
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 20 de Novembre de 2008
A les 13:00h
Resum/Resumen/Abstract

In the last decade, a combination of high sensitivity and spatial resolution observations in the extragalactic domain, and of coordinated multi-wavelength campaigns on galactic objects have revolutionized our understanding of black holes astrophysics on all mass scales. This has led to substantial progress towards super-unification schemes for active galactic nuclei, in which the large variety of different AGN classes can be classified based on fundamental physical parameters only, such as mass, accretion rate and kinetic energy output. I will describe the constraints available from a study of AGN evolution models on the growth of the SMBH population in the two main 'modes' observed (kinetic- and radiatively-dominated, respectively). SMBH always show a very broad accretion rate distribution, and I'll discuss the consequences of this fact for our understanding of observed AGN fractions in galaxies. I will show how SMBH mass function evolves anti-hierarchically, i.e. the most massive holes grew earlier and faster than less massive ones, and I will also derive tight constraints on the average radiative efficiency of AGN. Finally, constraints on the redshift evolution of the AGN kinetic luminosity function will be discussed and compared with the radiative output of the evolving SMBH population, thus providing a robust physical framework for phenomenological models of AGN feedback within structure formation.


Contacte/Contacto/Contact mribo@am.ub.es (Marc Ribó)
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Titulo/Titol/Title A radio view of massive stars
Conferenciant/Conferenciante/Speaker Dra. Paula Benaglia
Institucio/Institucion/Institution Instituto Argentino de Radioastronomia. La Plata, Argentina
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505 (Planta 5a)
Dimarts, 17 de Febrer de 2009
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title HI observations of Superthin Galaxies
Conferenciant/Conferenciante/Speaker Dr. Juan Usón
Institucio/Institucion/Institution National Radio Astronomy Observatory, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505 (Planta 5a)
Dijous, 19 de Febrer de 2009
A les 12:00h
Resum/Resumen/Abstract

Superthin galaxies are bulgeless, late-type spiral galaxies seen edge-on. HI synthesis observations probe the kinematic structure of their interstellar medium. I shall present the results of high-sensitivity VLA observations of UGC7321, IC2233, UGC3697 and UGC10043. Two of these galaxies are rather isolated while the other two are the dominant members of small groups


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Distributions of galactic lambda spin parameters: a comparison between cosmological simulations and measurements from the SDSS
Conferenciant/Conferenciante/Speaker Dr. Xavier Hernández Doring
Institucio/Institucion/Institution Instituto de Astronomía UNAM, México
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505 (Planta 5a)
Dijous, 26 de Febrer de 2009
A les 12:00h
Resum/Resumen/Abstract

Using simple dimensional arguments for both spiral and elliptical galaxies, we present formulas to derive an estimate of the halo spin parameter lambda for any real galaxy in terms of simple observational parameters. We apply this to a large volume limited sample of galaxies taken from the SDSS data base. The large numbers involved (11,597) allow the derivation of lambda distributions with high accuracy. We find that if the observed distribution of lambda is modeled with a log-normal function, as often done for this distribution in dark matter halos that appear in cosmological simulations, we obtain parameters lambda_{0}=0.04 +- 0.005 and sigma_{lambda}=0.51 +- 0.05, interestingly consistent with values derived from simulations. For spirals, we find a good correlatio between empirical values of lambda and visually assigned Hubble types, highlighting the potential of this physical parameter as an objective classification tool. For the observed distributions a marked anti-correlation between lambda and mass is found, while in N-body cosmological simulations lambda and mass appear to be independent of each other. Recent results concerning angular momentum correlations and alignment for pairs of spirals will also be commented on.


Contacte/Contacto/Contact eduard@am.ub.es (Eduard Salvador)
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Titulo/Titol/Title Telescopi Joan Oró de l'Observatori Astronòmic del Montsec: primer anunci d'oportunitat
Conferenciant/Conferenciante/Speaker Dr. David Fernández
Institucio/Institucion/Institution Institut de Ciències del Cosmos, Universitat de Barcelona
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Graus antiga
Dimecres, 25 de Març de 2009
A les 12:00h
Resum/Resumen/Abstract

En aquest seminari es presentarà la situació actual del Telescopi Joan Oró (TJO) de l'Observatori Astronòmic del Montsec (OAdM) i el primer anunci d'oportunitat de l'instrument, que oferirà temp d'observació a risc compartit a partir de l'1 de maig. Actualment el TJO treballa en règim de robotització total assistit, i a partir del segon semestre de 2009 començarà a treballar en mode robòtic sense supervisió. A la xerrada es presentarà la instrumentació disponible i les seves principals caractersítiques, el mode d'operació del telescopi, i també s'analitzaran els resultats obtinguts durant la fase de comissioning de l'instrument (juliol de 2008 - febrer de 2009), que confirmen la idoneïtat del lloc per a l'observació astronòmica.


Contacte/Contacto/Contact david.fernandez@am.ub.es (David Fernández)
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Titulo/Titol/Title Our Galactic Neighbourhood -- a Melting Pot of Migration
Conferenciant/Conferenciante/Speaker Dra. Brigitta Nordström
Institucio/Institucion/Institution Niels Bohr Institute, Copenhagen University, Dinamarca
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Juntes nova
Dimarts, 31 de Març de 2009
A les 12:00h
Resum/Resumen/Abstract

Spiral galaxies are an important part of the visible Universe. In the prototype, our own Milky Way, we can observe the most important component of a spiral galaxy -- the disk -- in unprecedented detail. In the Solar neighbourhood we can determine the numbers, ages, detailed chemical compositions, and galactic orbits of stars from the entire history of the disk with a completeness and accuracy not available anywhere else in the Universe. Therefore, the solar neighbourhood is a fundamental benchmark for all models of the evolution of galaxy disks. The Geneva-Copenhagen Survey (Nordström et al. 2004 and Holmberg et al. 2007, 2008) has full spatial, kinematic, metallicity and age information for 14,000 long-lived stars and provides a rich source of data for tests of models of evolution and formation of the Galaxy. We find that classical evolution paradigm of gradual enrichment and dynamical heating of the Galactic disk seem to fail several of the standard tests related to the stellar metallicity distribution, age-metallicity relation, and age-velocity relation. Both dynamical and kinematic evolution need to be taken into account in sufficient detail by the models to match the best data. A search for signatures of past accretion events in the Milky Way (Helmi et al. 2006) has yielded evidence of ancient substructure in the Galactic Disk and a project to study possible chemical signatures is ongoing.


Contacte/Contacto/Contact cesca@am.ub.es (Francesca Figueras)
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Titulo/Titol/Title The Star Formation Rate in Turbulent Clouds
Conferenciant/Conferenciante/Speaker Dr. Paolo Padoan
Institucio/Institucion/Institution University of California, San Diego, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula Pere Pascual (507), Planta 5
Dijous, 14 de Maig de 2009
A les 12:00h
Resum/Resumen/Abstract

Supersonic MHD turbulence is ubiquitous in star-forming regions and plays an important role in their dynamics and in the star-formation process. Based on the effect of turbulence, theoretical models for the mass distribution of stars and their formation rate have been proposed. This talk will discuss numerical simulations capable of testing and guiding theoretical models of the star formation rate. It will also address the use of observational data to validate the simulations and their assumptions, particularly through the Zeeman effect in dense cores.


Contacte/Contacto/Contact torrelles@ieec.fcr.es (José María Torrelles)
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Titulo/Titol/Title Històries de formació estel.lar de galàxies del Grup Local
Conferenciant/Conferenciante/Speaker Dra. Carme Gallart
Institucio/Institucion/Institution Instituto de Astrofísica de Canarias
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula Eduard Fontseré
Dilluns, 18 de Maig de 2009
A les 12:45h
Resum/Resumen/Abstract

Estem portant a terme un estudi detallat de les histories de formació estelar d'un conjunt de galaxies del Grup Local, a partir de diagrames color-magnitud que arriben fins als 'turnoff' vells de la sequència principal. En aquesta xerrada descriuré les motivacions i resultats principals de dos projectes: LCID (Local Cosmology from Isolated dwarfs), en el marc del qual hem obtingut una gran quantitat de dades amb la càmera ACS al HST de cinc galaxies nanes aïllades, i un projecte d'estudi dels Nuvols de Magallanes, per el qual hem obtingut dades amb la càmera de gran camp del 4m de CTIO. També discutiré amb bastant detall el nostre procediment d'obtenció de les histories de formació estelar, emprant els programes IAC-star y IAC-pop, que hem posat a disposició de la comunitat a través de la web.


Contacte/Contacto/Contact lola.balaguer@am.ub.es (Lola Balaguer)
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Titulo/Titol/Title Cross correlation of CMB anisotropies with large-scale structure: Toward a complete understanding
Conferenciant/Conferenciante/Speaker Dr. Jaiyul Yoo
Institucio/Institucion/Institution Harvard University, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Aula 505, Planta 5
Dimecres, 20 de Maig de 2009
A les 12:00h
Resum/Resumen/Abstract

We provide a general relativistic description of galaxies as a cosmological probe and discuss its implications for the cross correlation of cosmic microwave background (CMB) anisotropies with large-scale structure. The observed redshift and position of galaxies are affected by the Sachs-Wolfe and the gravitational lensing effects, and the constructed volume element is different from the true volume element. Consequently, the observed galaxy fluctuation field contains additional contributions from the volume distortion. Therefore, the cross correlation of CMB anisotropies with large-scale structure arises, not only from the cross correlation of the integrated Sachs-Wolfe effect in CMB anisotropies with the underlying matter density of large-scale structure as is assumed in the standard method, but also from the auto correlation of the integrated Sachs-Wolfe effect in both CMB anisotropies and large-scale structure and its cross correlation with the other contributions from the volume distortion in large-scale structure. We find that these new contributions are comparable to the cross correlation with the matter density and our accurate calculation of the cross correlation is significantly larger at low angular multipoles than in the standard method, above the current measurement uncertainties. Furthermore, these new contributions are essential for the gauge-invariance of observable quantities. We also compute the contributions of the primordial gravity waves and extend the linear bias approximation to the horizon scale. Our results are presented in the conformal Newtonian and the synchronous gauges, providing physical understanding of our general formalism.


Contacte/Contacto/Contact miralda@icc.ub.edu (Jordi Miralda)
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Titulo/Titol/Title Proyección y deproyección de objetos astronómicos elipsoidales
Conferenciant/Conferenciante/Speaker Dr. Eduardo Simonneau
Institucio/Institucion/Institution Institut d'Astrophysique de Paris
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Juntes Nova
Dimarts, 26 de Maig de 2009
A les 12:00h
Resum/Resumen/Abstract

La forma observada de muchos objetos astronómicos (galaxias elípticas, bulbos de galaxias espirales) puede considerarse con gran precisión como una elipse, que se puede identificar como la proyección sobre un plano de observación de un elipsoide. Por otro lado las estructuras elipsoidales pueden justificarse dentro de la teoría de los fluidos autogravitantes. Discutiremos cómo es la forma y posición de la elipse proyectada según sea la forma y posición de los elipsoides y qué es lo que se puede decir de estas últimas: forma y posición espacial de los elipsoides a partir de los elipsoides observados


Contacte/Contacto/Contact ramon@am.ub.es (Ramon Canal)
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Titulo/Titol/Title Modern Astronomy in Egypt
Conferenciant/Conferenciante/Speaker Dr. Ibrahim Sellim
Institucio/Institucion/Institution Kottamia Observatory (El Cairo)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time

Aula 505, Planta 5 Dijous, 2 de Juliol de 2009
A les 12:00h
Resum/Resumen/Abstract

Astronomy in Egypt is an old science since the time of Pharaohs when the first calendar appeared on the banks of Nile. In my talk I will first brievely review the history of modern optical astronomy in Egypt, its current status and the future research projects in collaboration with foreign astronomical groups. In the second part of my talk I will focus on my field of interest: Optical and Radio Extra-galactic Astronomy and the evolution of galaxies in groups. Compact groups (CGs) of galaxies provide ideal laboratories for studying galaxy-galaxy interactions, star formation activity and HI content. They constitute a unique environment to study galaxy interactions because of their high space density and low velocity dispersion (Hickson et al. 1992). Apparent densities do not only exceed the values seen in the cores of rich clusters of galaxies, but their small populations (less than 10 bright galaxies per group) make an analysis of tidal features and diffuse optical light much simpler than in core of the cluster.


Contacte/Contacto/Contact eduard@am.ub.es (Eduard Salvador)
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Titulo/Titol/Title Ancient substructures in the Galactic disk: chemical composition study
Conferenciant/Conferenciante/Speaker Dr. Grazina Tautvaisiene
Institucio/Institucion/Institution Vilnius University, Lituania
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dimarts, 22 de Setembre de 2009
A les 16:00h
Resum/Resumen/Abstract

From high resolution spectra taken with the spectrograph FIES on the Nordic Optical Telescope, La Palma, we measure abundances of oxygen and alpha-elements in order to characterize stars which from their dynamical properties are suspected to have originated in disrupted satellites. We find that the chemical composition of investigated stars is homogeneous and distinct from Galactic disk dwarfs, which is providing further evidence of their extragalactic origin.


Contacte/Contacto/Contact lola.balaguer@am.ub.es (Lola Balaguer)
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Titulo/Titol/Title Desintegración explosiva de un sistema de estrellas jóvenes en Orión
Conferenciant/Conferenciante/Speaker Dr. Luis Zapata
Institucio/Institucion/Institution Max Planck Institut fuer Radioastronomie
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dimecres, 23 de Setembre de 2009
A les 12:00h
Resum/Resumen/Abstract

En esta charla presentaré los resultados de nuevas observaciones interferométricas realizadas con el "Submillimeter Array" que indican que el enigmático flujo molecular localizado en la región de formación estelar Orión BN/KL ha sido producido durante una violenta desintegración de un sistema de estrellas jóvenes y masivas. La desintegración de este sistema de estrellas fue producido por una interacción dinámica entre sus miembros hace unos 500 años. Nuestro estudio revela que este flujo pertenece a una familia totalmente diferente de flujos moleculares y no al clásico flujo molecular generado por una estrella durante su formación. Adicionalmente, nuestras observaciones también nos han permitido recrear un mapa en 3D del flujo y conectarlo con los conocidos "fingers" o dedos detectados en H2. Finalmente, discutiré brevemente este resultado en el contexto de la formación de estrellas masivas.


Contacte/Contacto/Contact Robert Estalella (robert.estalella@am.ub.es)
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Titulo/Titol/Title Deciphering Cygnus X-3: an overview of its X-ray and radio behavior
Conferenciant/Conferenciante/Speaker Dra. Diana Hannikainen
Institucio/Institucion/Institution TKK/Metsähovi Radio Observatory (Finlandia)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dilluns, 19 d'Octubre de 2009
A les 12:00h
Resum/Resumen/Abstract

The X-ray binary Cygnus X-3 has been extensively observed since its discovery in the late 1960s but its true nature still remains elusive. It is one of the brightest X-ray and radio sources in the Galaxy and its behavior in both domains is very erratic. Cygnus X-3 is notorious for undergoing major radio flares brighter than those of any other X-ray binary. When simultaneous radio imaging was available, it was shown that these flares were associated with relativistic ejections. The true nature of the source remains elusive, although the identification of the companion star as a Wolf-Rayet is fairly robust, classifying it a as a high-mass X-ray binary. However, the nature of the compact object is still an enigma, although recent work hints at a black hole. In this talk, I will review Cygnus X-3's X-ray and radio properties and discuss some of the more recent multiwavelength campaigns dedicated to understanding this source better.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Exploring the MOND paradigm
Conferenciant/Conferenciante/Speaker Dr. Olivier Tiret
Institucio/Institucion/Institution SISSA (Trieste, Italy)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dimarts, 24 de Novembre de 2009
A les 12:00h
Resum/Resumen/Abstract

I use numerical simulations to explore an alternative to the Newtonian gravity: MOND, where the modification of the gravity follows an acceleration scaling law, without invoking any dark matter. This gravity is non-linear and needs more sophisticated methods than those which are used for Newtonian gravity with dark matter. I will present the results of N-body simulations for isolated galaxies and interacting galaxies, in both frameworks of modified gravity and Newtonian gravity with dark matter. The stability of the discs, the angular momentum transfers and the dynamical friction are studied to bring some constraints and to test the different scenarios


Contacte/Contacto/Contact xluri@am.ub.es (Xavier Luri)
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Titulo/Titol/Title High-energy emission from jet/cloud interactions in AGNs
Conferenciant/Conferenciante/Speaker Anabella Araudo
Institucio/Institucion/Institution Instituto Argentino de Radiastronomia (La Plata)
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 19 de Febrer de 2010
A les 12:00h
Resum/Resumen/Abstract

Active galactic nuclei (AGN) are extragalactic sources that present continuum and line emission in the whole electromagnetic spectrum. The continuum radiation is produced by an accretion disk and relativistic jets. The emission lines are originated by gas located close to the central super-massive black hole (SMBH). Some of these lines are broad, and would be produced in a small region called broad-line region (BLR). The BLR structure is not well known, although it has been proposed that it is formed by small and dense clouds surrounding the SMBH. In this talk, I will discuss the interaction of these clouds with the base of the jet, and the production of high-energy photons. The resulting radiation may be significant, and its detection could give important information on the properties of the jet base and BLR of AGNs. Also, jet/cloud interactions may be behind the variable emission detected in some AGNs.


Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Separating expansion from collapse and generalizing TOV condition in spherically symmetric models with pressure, with Lambda-CDM examples
Conferenciant/Conferenciante/Speaker Dr. Morgan Le Delliou
Institucio/Institucion/Institution Universidad Autónoma de Madrid
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 27 de Maig de 2010
A les 12:00h
Resum/Resumen/Abstract

The Press-Schechter scheme for mass functions invokes Birkhoff's theorem in the spherical collapse that yields non-linear collapse time. However, the theorem is only proven for asymptotic flatness(vacuum background). We investigate spherically symmetric solutions with pressure and discuss the existence of a dividing shell separating expanding and collapsing regions, for which we obtain gauge invariant conditions relating not only the intrinsic spatial curvature of the shells to the mass, but also a function of the pressure which we introduce and that generalises the Tolman-Oppenheimer-Volkov equilibrium condition.


Contacte/Contacto/Contact amanri@am.ub.es (Alberto Manrique)
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Titulo/Titol/Title Physical properties of the Sh2-104 and RWC 120 HII regions as seen by Herschel
Conferenciant/Conferenciante/Speaker Dr. Javier A. Rodón
Institucio/Institucion/Institution Laboratoire de Marseille
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Divendres, 28 de Maig de 2010
A les 12:00h
Resum/Resumen/Abstract

The Herschel space observatory has provided for the first time observations in the far-IR window, unaccessible for ground-based observatories. Its photometric and spectroscopic instruments have uncovered many new insights into the different star formation processes in the Galaxy. In this opportunity I will present Herschel data obtained with the PACS and SPIRE instruments during the telescope's science demonstration phase. After a brief introduction on the Herschel space observatory and its instruments, I will focus on the two Galactic HII regions Sh2-104 and RWC 120. These regions show signs of triggered star formation, and are excellent laboratories to investigate star formation occurring simultaneously at different evolutionary stages. In particular, I will present a photometric study on the dust content of the two regions showing an anti-correlation between the dust temperature and the dust emissivity index. Also, I will discuss our preliminary spectroscopic analysis of Sh2-104, determining gas temperatures and column densities.


Contacte/Contacto/Contact gbusquet@am.ub.es (Gemma Busquet)
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Titulo/Titol/Title Accretion states and thermonuclear bursts in neutron star X-ray binaries
Conferenciant/Conferenciante/Speaker Dr. Manuel Linares
Institucio/Institucion/Institution Massachusetts Institute of Technology - Kavli Institute for Astrophysics and Space Research, Cambridge, USA
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dijous, 17 de Juny de 2010
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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Titulo/Titol/Title Radio detections of ULX sources
Conferenciant/Conferenciante/Speaker Mar Mezcua
Institucio/Institucion/Institution Max Planck Institute for Radio Astronomy, Bonn
Lloc, Data i Hora
Lugar, Fecha y Hora
Room, Date and Time
Sala de Seminaris, Planta 7
Dilluns, 6 de Setembre de 2010
A les 12:00h
Resum/Resumen/Abstract



Contacte/Contacto/Contact jmparedes@ub.edu (Josep Maria Paredes)
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