Seminars
Displaying 401 - 450 of 1201
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13/11/2014 - 13:30
Unveiling the Massive Stars in the Galactic Centre Because of the proximity, the Galactic Centre is an unique lab for studies of the interplay between stars, ISM and super massive black holes in galactic nuclei. The central 200 pc of the Galactic Centre includes 4x10^7 molecular clouds and has a star formation rate of ~0.03 M/yr. Three young, massive and compact star clusters were found and includes around 100 massive stars, which shape the nearby ISM. However, the... Dr. Hui Dong |
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30/10/2014 - 13:30
The non-thermal universe at the highest energies: TeV gamma-ray astronomy with the MAGIC telescope Some os the most violent processed in the universe present a non-thermal spectrum reaching energies of several tens of TeV. Due to the low fluxes at these energies, we need a technique capable to achieve collection areas of the order of the km^2. This can be reached by the Imaging Atmospheric Cherenkov technique and MAGIC is one of the main detectors for performing ground-based observations using this technique. It consists of two 17m... Rubén López-Coto |
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22/10/2014 - 14:30
High Frequency Astrometry and Pulsar Studies with the Korean VLBI Network Maria Rioja will report on the Korean VLBI Network (KVN), the first dedicated mm-VLBI array. The 3 telescopes have an innovative multifrequency receiver that allows for simultaneous observations at 22, 43, 86 &129GHz. With care these can be phase referenced to allow astrometry at these frequencies. I will show our first results of phase referencing at 132GHz and the path to compatible global VLBI. Richard Dodson will discuss a... María Rioja and Richard Dodson |
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16/10/2014 - 14:30
The Fingerprint of a Galactic Nucleus: A Multi-Wavelength, High-Angular Resolution, Near Infrared Study of the Centre of the Milky Way The centre of the Milky Way is the only galactic nucleus and the most extreme astrophysical environment that we can examine on scales of milli-parsecs. It is therefore a crucial laboratory for studying galactic nuclei and their role in the context of galaxy evolution. Yet, suitable data that would allow us to examine the stellar component of the Galactic Centre exist for less than 1% of its projected area. This ERC-funded research programme... Dr. Rainer Schödel |
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15/10/2014 - 14:30
OCTOCAM: Proposal for a multichannel imager and spectrograph with high-time-resolution capabilities for the 8.1m Gemini telescopes OCTOCAM is a multichannel imager and spectrograph that we will be proposing in the months to come for the 8.1m Gemini telescopes, in response to a call for feasibility studies of new instruments that has been recently opened. It will use dichroics to split the incoming light to obtain simultaneous observations in 8 different bands, from the ultraviolet to the near infrared. In its imaging mode, it will have a field of view of around 3'x3... Dr. Antonio de Ugarte Postigo |
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24/09/2014 - 14:30
Metamateriales Quirales, el Plan B para la Refracción Negativa Metamateriales, más allá de los materiales, con este término se engloba una amplia variedad de materiales artificiales cuyas propiedades van más allá de las que nos proporciona la naturaleza. Mayor resistencia, extremada ligereza, propiedades exóticas o comportamientos anómalos ante la radiación son algunas de las características que estamos buscando. En esta charla... Dr. Gregorio José Molina Cuberos |
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03/07/2014 - 14:30
'What is the progenitor system of the nearby Type Ia SN 2014J?' Type Ia supernovae (SNe Ia) are the thermonuclear explosive end-products of white dwarfs. SNe Ia are primary cosmological distance indicators and a major contributor to the chemical evolution of galaxies, yet we do not know what makes a SN Ia. There are two basic families of models leading to a SN Ia, the single- degenerate model (SD) and the double-degenerate model (DD). In the SD scenario, a WD... Dr. Miguel Ängel Pérez Torres |
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26/06/2014 - 14:30
The brief lives of massive stars as witnessed by interferometry Massive stars present the newest and perhaps most challenging opportunity for long baseline interferometry to excel. Large distances require high angular resolution both to study the means of accreting enough mass in a short time and to split new-born multiples into their components for the determination of their fundamental parameters. Dust obscuration of young stellar objects require interferometry in the infrared, while post-... Dr. Christian Hummel |
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24/06/2014 - 14:30
Remote sensing: survival strategies in the jungle of averaging kernels and covariance matrices Outer space, stars, exoplanets, planets in the solar system, and even the Earth's middle and upper atmosphere have in common that it is inconvenient, expensive, and often technically unfeasible to make in situ measurements there. Remote sensing, e.g., by means of radiance measurements, is a relatively cheap and convenient alternative. The conversion of the measured radiances to the quantities of interest, e.g., temperature and composition... Dr. Thomas von Clarmann |
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05/06/2014 - 14:30
Status of Astronomy in East Africa Activities of astronomy in East Africa are driven the East African Astronomical Society (EAAS) supported mainly by the IAU/OAD. A positive trend in the development of astronomy activities in the region is characterised by the inclusion of astronomy into the curriculum at all levels, construction of astronomy observatories and research centres (e.g. Entoto Observatory -first light last week), opening new MSc... Dr. Pheneas Nkundabakura |
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29/05/2014 - 14:30
IAA Computing Service A cluster is defined as a collection of interconnected stand-alone workstations or PCs cooperatively working together as a single, integrated computing resource. Cluster Computing has become the paradigm of choice for executing large-scale science, engineering, and commercial applications. This is due to their low cost, high performance, availability of off-the-shelf hardware components and freely accessible software tools that that can be... Rafael Parra |
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15/05/2014 - 14:30
Deep spectroscopy of planetary nebulae In nebulae astrophysics, there are two long-standing discrepancies: 1) the ionic and elemental abundances of C, N, O, and Ne derived from optical recombination lines (ORLs) are systematically higher than those derived from collisionally excited lines (CELs); 2) the electron temperature derived from H I recombination continuum (e.g., Balmer jump at 3646 A) is always lower than that derived from CELs. These two... Dr. Xuan Fang |
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24/04/2014 - 14:30
Inconsistences in the harmonic analysis of time series The power of asteroseismology relies on the ability to infer the stellar structure from the unambiguous frequency identification of the correspoinding pulsation mode. Hence, the use of a Fourier transform is in the basis of asteroseismic studies. Nevertheless, the difficulties with the interpretation of the frequencies found in many stars lead us to reconsider Fourier analysis and the classical methods used to process time series... Javier Pascual Granado |
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10/04/2014 - 14:30
Sculpting the Galactic Centre: Astrophysics and fundamental physics with photons and gravitational waves Since 1993 we have known that the Galactic Center (GC) displays a core-like distribution of red giant branch (RGB) stars starting at ~ 1'', which poses a theoretical problem, because the GC should have formed a segregated cusp of old stars. I postulate that the reason for the missing stars in the RGB is closely intertwined with the formation of a formerly existing dense gas disk, an episode that removed the... Dr. Pau Amaro-Seoane |
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08/04/2014 - 14:30
The IAA Cloud Service The rise in speed of communications and the decline in prices of storage elements, has caused we can put some of our information on the net in order to make it available easily from anywhere. In this sense, it is said that your information is hosted in the cloud. Nowadays, there are several software solutions to sync and sharing files on the cloud, like Dropbox, Google Drive or Sky Drive, among others. In the IAA, a cloud... Francisco Manuel Bayo Muñoz and Juan José Guijarro Jiménez |
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03/04/2014 - 14:30
A ring system detected around the Centaur (10199) Chariklo We will report observations of a multichord stellar occultation that revealed the presence of a ring system around the centaur object (10199) Chariklo. There are two dense rings,with respective widths of about 7 and 3 kilometres, optical depths of 0.4 and 0.06, and orbital radii of 391 and 405 kilometres. We will also present more results obtained after the occultation on June 3rd 2013. Photometric and spectroscopic... Dr. Rene Duffard |
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27/03/2014 - 13:30
New findings on the X-ray emission from Wolf-Rayet nebulae We present the most recent results of XMM-Newton and Chandra observations on the only four Wolf-Rayet (WR) nebulae observed to date. Given the limited number of observations and the different morphological and spectral characteristics of these nebulae, it has been difficult to understand the physics behind the plasma emission. Numerical and analytical models can not explain the 'soft' nature and low plasma temperatures (T~106 K)... Jesús A. Toalá |
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20/03/2014 - 13:29
The Nature of the IR Emission in Low-Luminosity AGN at Parsec Scales The vast majority of AGN belong to the low-luminosity class (LLAGN): they exhibit a low radiation efficiency (L/Ledd < 10^-3) and the absence of the big blue bump in their spectra, a signature of the accretion disk. The study of LLAGN is a complex task due to the contribution of the host galaxy, whose light outshines these faint nuclei. As a consequence, numerical models are usually compared with relatively poorly defined spectral energy... Juan Antonio Fernández Ontiveros |
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13/03/2014 - 13:30
Quasars and their emission lines as cosmological probes Quasars are the most luminous stable sources in the Universe. They are currently observed out to redshift z ~ 7 when the Universe was less than one tenth of its present age. Since their discovery 50 years ago astronomers have dreamed of using them as standard candles. Unfortunately quasars cover a very large range (8 dex) of luminosity making them far from standard. I briefly review several methods that can potentially exploit quasars... Dr. Paola Marziani |
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06/03/2014 - 13:30
La Asociación de Mujeres Investigadoras y Tecnólogas (AMIT) La incorporación de la mujer a la investigación, la docencia o la gestión de la Ciencia y las Humanidades supone un progreso social. La participación de las mujeres en estas esferas, sin embargo, no es igualitaria respecto a los hombres en la España de comienzos del siglo XXI. La presencia de la mujer es dramáticamente decreciente a medida que se sube en los escalones profesionales. AMIT es una... J. Masegosa |
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20/02/2014 - 13:30
The AGN nature of LINER nuclear sources The origin of the main excitation mechanisms in LINER (Low Ionization Emission Line Region) nuclei are still controversial, with nonstellar photoionization, fast shocks or hot stars as the principal candidates. In the AGN scenario, LINERs could represent the link between more powerful AGN and normal galaxies as suggested by their low X-ray luminosities. Their interest increases as they would be the dominant population of active... Dr. I. Márquez |
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13/02/2014 - 13:30
A powerful new method to measure the atmospheric water vapour column. We have developed a reliable powerful method to measure the atmospheric column of water vapour (PWV) down to very low levels. For this purpose we use and off-the-shelf cheap spectrometer to measure the equivalent width of the H2O bands at 940nm. In order to calibrate the measurements we use the radiative transfer model included in the package SCIATRAN to produce theoretical solar spectra as observed on the ground, based on simultaneous... Prof. E. Pérez |
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06/02/2014 - 13:30
The bricks of the Very Large Telescope Interferometer In this talk we will perform a review of the basic principles of the optical/near-infrared interferometry and of the current European facilities to use this observational technique. Particularly, we will describe the interferometric observables used at near-infrared wavelengths. We will provide a review of the current (and future) instruments available at the ESO Very Large Telescope Interferometer (VLTI), their advantages and limitations as... Lic. Joel Sánchez Bermúdez |
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30/01/2014 - 13:30
The CHESS survey of the protostellar shock L1157-B1 Outflows generated by protostars heavily affect the kinematics and chemistry of the hosting molecular cloud due to strong shocks. These shocks heat and compress the ambient dense gas switching on a complex chemistry that leads to an enhancement of the abundance of several species, as reported in "chemically active" outflows, whose archetype is the outflow of the low-mass Class 0 protostar L1157. I'll present the results of... Dr. Gemma Busquet |
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23/01/2014 - 13:30
Nucleosynthesis and molecular processes in evolved stars Most of the stars (M < 8 solar masses) in the Universe end their lives with a phase of strong mass loss and experience thermal pulses (TP) on the Asymptotic Giant Branch (AGB), just before they form Planetary Nebulae (PNe). They are one of the main contributors to the enrichment of the interstellar medium and thus to the chemical evolution of galaxies. More specifically, the more massive AGB stars form very different isotopes (such as... Dr. Anibal García Hernández |
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16/01/2014 - 13:30
Bar parameter evolution over the last 7 Gyr The tumbling pattern of a bar is the main parameter characterising its dynamics. This bar pattern speed, the bar ellipticity and its length are the three observational parameters that fully characterize bars. From numerical simulations, their evolution since bar formation is tightly linked to the dark halo in which the bar is formed through dynamical friction and angular momentum exchange. Observational ... Dr. Isabel Pérez |
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05/12/2013 - 13:30
Stellar water fountains: planetary nebulae in the making Planetary nebulae (PN) are one of the final phases in the evolution of low and intermediate mass stars (<8 Msun). They display a great variety of shapes, although in their previous phases (Asymptotic giant branch =AGB) they have a spherical geometry. The transition from spherical symmetry to asymmetry must occur during the short post-AGB phase or in the early PN phase. Here we present a special type of evolved stars, called "... Dr. JFrancisco Gómez |
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28/11/2013 - 13:30
Galaxy clusters: galaxy laboratories and cosmological probes. A see you later seminar. In this talk -my last one in the IAA for the moment- I will talk about the largest structures in the Universe: galaxy clusters. The first part of the talk will be focused on galaxy clusters embedded in the large scale structure: how we detect them and how we can use them to provide estimations of cosmological parameters. In the second part, I will talk about the galaxies living in clusters, in particular, about the brightest cluster... Dr. Begoña Ascaso |
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07/11/2013 - 13:30
Proposing observations with the European VLBI Network The European VLBI Network (EVN) is currently the most sensitive VLBI array in the world (its collecting area is about a hundred thousand square meters, or 1/10 of the planned Square Kilometer Array). I will give an overview of the EVN and the kind of science being done with this radio interferometric array, which essentially goes from Solar System studies up to quasars at high redshift. As a member of the EVN Programme Committee, I will... Dr. Miguel Angel Pérez-Torres |
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31/10/2013 - 13:30
Digital Science: towards the executable paper The science performed in Astronomy is digital science. This fact does not prevent the final outcome of an experiment is still difficult to reproduce. J. E. Ruiz |
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24/10/2013 - 14:30
AGN feedback and accretion in Perseus A The Perseus Cluster is known as a famous observational example of (radio-mode) AGN feedback driven by the radio jet of the central galaxy Perseus A (NGC 1275, 3C 84). The feedback process is evident from observations of the intra-cluster medium showing X-ray bubbles filled with radio plasma. The radio jet generating these bubbles is powered by accretion onto the supermassive black hole in Perseus A. In this talk, I will present our results... Dr. Julia Scharwächter |
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17/10/2013 - 14:30
The Martian ionosphere The ionospheres of the planets (those regions with a significant fraction of free electrons and ions) provide interesting clues about the interaction of the solar radiation and the solar energetic particles with the planetary atmospheres.They can also be used to gain information about the density and temperature of the neutral upper atmospheres, a region that in the Martian case has traditionally eluded observation. In this talk I will sketch... Dr. Francisco González Galindo |
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10/10/2013 - 14:30
Hot potatoes: the compact obscured nuclei of dusty IR galaxies Evidence is now mounting that most of the activity in some luminous infrared galaxies takes place in their compact obscured nuclei (CONs), regions of less than 100~pc in diameter, which harbor large amounts of warm (T$>$100~K) molecular material (N(H$_2$)$>10^{24}$~cm$^{-2}$). The combined effect of warm, shielded gas and intense infrared radiation produce rich molecular spectra, which make these objects unique laboratories to study... Dr. Francesco Costagliola |
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03/10/2013 - 14:30
Spectroscopy of the short GRB 130603B: The host galaxy and environment of a compact object merger The nature of short duration gamma-ray bursts (GRBs) remains a central problem of modern astrophysics. They are thought to be related to the violent merger of compact objects, such as neutron stars or black holes, which would make them promising sources of gravitational waves. The absence of supernovae signatures clearly indicates that SGRB progenitors differ from their long duration cousins, but constraints to-date arise almost entirely from... Dr. Antonio de Ugarte Postigo |
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26/09/2013 - 14:30
Main-Belt Comets Since the discovery of 133P/Elst-Pizarro in 1996, an object moving in a typical Main Asteroid Belt orbit, but displaying a comet-like tail, nine more of those objects have been identified. They constitute a new class of small Solar System bodies, the ``missing link'' between asteroids and comets. Three of those objects fall into the ``disrupted asteroids'' subgroup, where the activity is suspected to be driven by either a... Dr. Fernando Moreno |
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12/09/2013 - 14:30
Cosmological Simulations of Galaxy Formation We present a suite of simulated galaxies, that match a wide range of scaling relations over a large mass range at z=0, and follow the evolution of these relations and confront them with observational constraints. We then make connections to "galactic archaeology" by examining the nature of the major structural components of the discs, highlighting that far and near field cosmology can be combined using these types of simulations. We... Dr. Chris Brook |
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05/09/2013 - 14:30
SN 1993J and M81: a fruitful astrophysical collaboration SN1993J, a powerful radio supernova high in the northern sky, has been monitored with VLBI though its lifetime. The VLBI observations have been phase-referenced to the core of M81. We will highlight the main results obtained: its extremely circular shell-like radio structure has expanded over 15 years in a rather self-similar way; the expansion is wavelength dependent, a result which can be mainly explained by a combination of a varying free-... Prof. A. Alberdi |
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18/07/2013 - 14:30
Can we solve by solar magneto-seismology one of astrophysics great problems: Coronal heating enigma? The latest satellite and ground-based observations have provided us a wealth of evidence of waves and oscillations present in the solar atmosphere from the low photosphere to the upper corona. Our understanding of the magnetically dominated structures and their dynamics in the solar atmosphere has been considerably enhanced in light of the latest high spatial and temporal resolution observations (e.g. DST/ROSA, IBIS, CoMP, SST/CRISP; SOHO,... Prof. Robertus von Fay-Siebenberg |
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04/07/2013 - 14:30
The ALHAMBRA survey: First Data Release. The ALHAMBRA (Advance Large Homogeneous Area Medium Band Redshift Astronomical; Moles et al. 2008) survey has observed 8 different regions of the sky, including sections of the COSMOS, DEEP2, ELAIS, GOODS-N, SDSS and Groth fields using a new photometric system with 20 contiguous, ~300A width, filters covering the optical range, plus deep JHKs imaging. The observations, carried out with the Calar Alto 3.5m telescope using the wide field... Alberto Molino |
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27/06/2013 - 14:30
CALIFA tbd Dr. Sebastián Sánchez |
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20/06/2013 - 14:30
El Universo de Planck Recientemente se han presentado los resultados cosmológicos de la misión espacial Planck. Es un buen momento para poner al día el valor de los parámetros del Universo. La nueva composición se resume en 26.8% materia oscura, 4.9% materia visible, 68.3% energía oscura. El valor de la constante de Hubble ha resultado también muy inferior a lo esperado: 67.5 km/(s Mpc). La conclusión m... Prof. E. Battaner |
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13/06/2013 - 14:30
Love for Science or 'Academic Prostitution'? Note: This is a seminar given at the European Research Council Headquarter some weeks ago. It was focused on the expected audience, members of the ERC directly involved in setting the rules for Grants evaluation and/or participate in all steps of the process, mainly Scientific Officers, but also Agency staff. I have decided to present the talk as it was presented there. Abstract: In a recent Special issue of Nature concerning Science... Dr. Lourdes Verdes-Montenegro |
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06/06/2013 - 14:30
PAH's in Titan's Upper Atmosphere Observations of Titan's atmosphere made with the VIMS instrument on board the Cassini satellite show a strong limb emission around 3.3 µm at high atmospheric altitudes (above 700 km). This emission exhibits the typical spectral signatures of the strong CH4 bands. A detailed analysis of the spectra reveals, however, an additional strong emission centered at 3.28 µm and peaking at about 950 km. We have untangled this spectral... Prof. Manuel López-Puertas |
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23/05/2013 - 14:30
Extreme emission-line galaxies: New light on the mass assembly and chemical enrichment of low-mass galaxies Galaxies showing early and significant stages of mass assembling are key objects for understanding galaxy evolution. However, young starbursts like these are extremely rare in the local Universe. In this context, a unique population of compact, low-mass galaxies forming stars at unusually high rates - also known as the "green peas" - emerge now as ideal laboratories to study the details of massive star formation, feedback and... Dr. R. Amorin |
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16/05/2013 - 14:30
Hall motions and star escape in galactic dynamics in the Hill approach The motion of a galactic cluster is approximately described by those equations in a co-moving frame, introduced by Hill in the XIXth century. Individual motions can only studied numerically, but for the center of mass interstellar gravitational forces drop out and one is left with a simply system analogous to those considered by Hall for a planar electron in crossed electric and magnetic fields. In both cases, the motion of the COM is... Dr. P. Horvathy |
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09/05/2013 - 14:30
The IAA COsmic DUst LABoratory, a lab next door (building). MAIN GOALS of this talk: 1. Let you know/remind you that the IAA has a worldwide reference light scattering laboratory for experimentally studying the angular dependence of the scattering matrices of dust samples of astrophysical interest. 2. Convince the audience of: - Polarization is highly valuable tool for retrieving information on the physical properties of small cosmic dust particles. - How useful laboratory measurements... Dr. O. Muñoz |
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25/04/2013 - 14:30
X-raying born-again planetary nebulae Planetary nebulae have been a addition to the zoo of X-ray-emitting sources. Here I present results on a the very particular class of born-again planetary nebulae, those whose central star has experienced a helium shell flash during the lifetime of the planetary nebula. The interaction of the fast stellar wind of the central star with hydrogen-poor material ejected during the born-again episode provides a unique case to study... Dr. M. Guerrero |
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18/04/2013 - 14:30
The Shortest-Known–Period Star Orbiting Our Galaxy’s Supermassive Black Hole Stars with short orbital periods at the centre of our Galaxy offer a powerful and unique probe of the nearest supermassive black hole. Observing these stars is a long-term astrophysical experiment that has been going on for two decades. In this talk I will outline this project and discuss the observational challenges and the strategies to overcome them. Steady technological and methodological advances allow us to improve... Dr. Rainer Schoedel |
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11/04/2013 - 14:30
CALIFA: The spatially resolved Star Formation History of Galaxies The Calar Alto Legacy Integral Field Area (CALIFA) is an ongoing 3D spectroscopic survey of 600 nearby galaxies of all kinds. This pioneer survey is providing valuable clues on how galaxies form and evolve. Processed through spectral synthesis techniques, CALIFA datacubes allow us to, for the first time, spatially resolve the star formation history of galaxies spread across the color-magnitude diagram. The richness of this approach is already... Dr. R. González Delgado |
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04/04/2013 - 14:30
Probing Galaxy-Scale Halos and Large-Scale Structure with Weak Gravitational Lensing The presence of dark matter in the Universe is well-established and contributes significantly to structures ranging from galaxies to superclusters. However, the details of the connection between luminous galaxies and the dark matter halos in which they reside are not particularly well-characterised. Weak gravitational lensing is the only direct probe that can measure the total mass profile associated with galaxies over a wide range of radii... Dr. Ami Choi |