Recent Talks
List of all the talks in the archive, sorted by date.
Wednesday March 11, 2009
Dr. Jordi Cepa
Instituto de Astrofísica de Canarias, Spain
Abstract
The standard scientific operations of the instrument OSIRIS will start at the GTC by mid March. The first tests of the instrument once mounted on the telescope are now finished and during this talk we will show the results of the instrument characterization and final performance. We will present the plans for the future commissioning of the remaining observing modes as well as the next implementations expected for OSIRIS.
Thursday February 26, 2009
Dr. Ángel de Vicente
Instituto de Astrofísica de Canarias, Spain
Abstract
If you do any amount of programming, you have certainly found that at some point during its development your code did not work as expected. Perhaps it simply crashed and told you that a core dump was created; perhaps it always gave you an "incorrect" result or perhaps it just behaved "oddly" given some input combinations. In any case, you were face to face with a "bug". And what did you do to correct your code? If the answer was to put "printf"s around the code and run it again, you should attend this talk in which we'll see an introduction on how to debug your programs with a debugger. The debugger (available for most programming languages) is a really easy-to-use tool that lets you run your application in a special mode, so that you can run it step by step, or stop at certain points, inspect variables, etc., which is a great aid to find what is wrong with your code without the need of changing its source.
Thursday February 19, 2009
Prof. Carlos Frenk
Institute for Computational Cosmology, Physics Dept, Durham University
Abstract
The standard model of cosmology -- the ``Lambda cold dark matter'' model -- is based on the idea that the dark matter is a collisionless elementary particle, probably a supersymmetric particle. This model (which mostly dates back to an early workshop in Santa Barbara in the 1980s) has been famously verified by observations of the cosmic microwave background radiation and the large-scale distribution of galaxies. However, the model has yet to be tested conclusively on the small scales appropriate to most astronomical objects, such as galaxies and clusters. I will review our current understanding of the distribution of dark matter on small scales which derives largely from large cosmological N-body simulations and I will discuss prospects for detecting dark matter, either through its gravitational effect on galaxies and clusters or, more directly, through gamma-ray annihilation radiation.
Tuesday February 10, 2009
Dr. Valentín Martínez Pillet
Instituto de Astrofísica de Canarias, Spain
Abstract
El instrumento IMaX ha sido entregado al proyecto SUNRISE, un telescopio solar de 1 m de diámetro que volará este verano desde el polo norte en un globo LDB de NASA. En este coloquio veréis como ha sido el proceso de integración del instrumento español IMaX y cual es el status del proyecto SUNRISE que involucra a tres países: EEUU, Alemania y España con la participación del IAC, IAA (Granada), INTA (Madrid), GACE (Valencia) y la UPM (Madrid).
Friday January 30, 2009
Dr. Saku Tsuneta
National Astronomical Observatory, Japan
Thursday January 29, 2009
Dr. Christopher Watson
University of Belfast, Northern Ireland
Abstract
SuperWASP is the UK's leading extra-solar planet detection program, having detected 22 of the 52 transiting planets known to date. This stems from the instruments ability to image ~500 square degrees every 60sec down to 16th mag (equivalent to the whole visible sky every 20 minutes). Recent experiments have shown that the data from SuperWASP can be reduced with 1 min of it being obtained and with further software development we will be able to identify transient sources within minutes of their observation. Detailed analysis of SuperWASP-N data has shown many populations of transient objects, including rapidly variable objects, which seem to correspond to extremely faint objects in the Sloan survey. Spectroscopy of these objects has proved challenging.
Wednesday January 28, 2009
Dr. Francesco Sylos Labini
Institute for Complex Systems, CNR, Italy
Abstract
The Sloan Digital Sky Survey is currently the largest spectroscopic survey of extragalactic objects and one of the most ambitious observational programs ever undertaken in astronomy, measuring about 1 million redshifts and thus providing a three dimensional mapping of the local universe up to a depth of several hundreds of Mpc. The main characteristic of galaxy distribution in this survey, and in the Two degree Field Galaxy redshift Survey completed few years ago, is that large scale structures have been found to extend to scales of the order of hundreds of mega parsecs. However the standard determination of a characteristic length scale, statistically describing galaxy correlations, is of only few mega parsecs: the standard explanation of this apparent mismatch is that large scale structures have small amplitude relative to the average density. We show that, in the newest galaxy samples, large scale structures are quite typical and correspond to large fluctuation in the galaxy density field, making the standard interpretation untenable. We show that the standard statistical analysis is affected by systematics which are due to inconsistent assumptions. We point out that standard theoretical models of structure formation are unable to explain the existence of the large fluctuations in the galaxy density field detected in these samples. This conclusion is reached in two ways: by considering the scale, determined by a linear perturbation analysis of a self-gravitating fluid, below which large fluctuations are expected in standard models and through the determination of statistical properties of mock galaxy catalogs generated from cosmological N-body simulations. Finally we discuss the implications of this results in relation to recent attempts to describe inhomogeneous models in general relativity and to the recent discoveries of large scale coherent bulk flows.
Monday January 26, 2009
Dr. Paolo Molaro
INAF, Osservatorio di Trieste, Italy
Abstract
Jan Brueghel depicted telescopes in four paintings spanning the period between 1609 and 1621. We have investigated the nature and the origin of these telescopes. An optical "tube" that appears in the painting dated 1608-1612, and probably reproduced also in a painting of the 1621, represents one the earliest documentation of a Dutch spyglass which could even tentatively attributed to Sacharias Janssen or Lipperhey, thus prior to those made by Galileo. Other two instruments made of several draw-tubes which appear in the two paintings of 1617 and 1618 are quite sophisticated for the period and we argue that may represent early examples of Keplerian telescopes.
Thursday January 22, 2009
Dr. Anne-Marie Weijmans
Leiden Observatory, the Netherlands
Abstract
From galaxy formation theory we expect galaxies to be embedded in massive dark matter haloes. For spiral and dwarf galaxies this has indeed been observationally confirmed, by modeling the kinematics from the large cold gas discs that often surround these galaxies. These gas discs are however rare in elliptical galaxies, so that we have to resort to other tracers when we want to probe their dark matter haloes, which are not always easily accessible. As a result, dark haloes for only a handful of early-type galaxies have been mapped. In this talk I will give an overview of the methods that can be used to find dark matter in early-type galaxies. I will then focus on two projects that I worked on with the integral-field spectrograph SAURON, using two different methods to constrain the dark halo. The first is based on the combination of two-dimensional ionised gas and cold gas kinematics. The second method uses SAURON as a 'photon collector', to obtain spectra at large radii in galaxies. From these spectra we can not only obtain the velocity profile and construct mass models to constrain the dark halo, but also infer the properties of the stellar halo population. I will show the results from these two projects and discuss some future prospects.
Wednesday January 21, 2009
Dr. Nadine Neumayer
European Southern Observatory, Garching, Germany
Abstract
The centers of massive galaxies are special in many ways, not least because all of them are believed to host supermassive black holes. Since the discovery of a number of relations linking the mass of this central black hole to the large scale properties of the dynamically hot component of its host galaxy (bulge) it has become clear that the growth of the central black hole is intimately connected to the evolution of its host galaxy. However, for bulge-less galaxies, the situation is much less clear. Interestingly, these galaxy often host star clusters in their nuclei, and unlike black holes, these nuclear star clusters provide a visible record of the accretion of stars and gas into the nucleus. I will present my ongoing projects on nuclear star clusters that aim to understand their formation process and might give a hint on how black holes get to the centers of galaxies.Upcoming talks
- Ciencia desde el espacio en España: hoja de ruta de la AEEDr. Isabel Pérez GrandeTuesday November 26, 2024 - 10:30 GMT (Aula)
- Revisiting mass transfer and accretion in symbiotic binaries in the Gaia eraDr. Jaroslav MercThursday November 28, 2024 - 10:30 GMT (Aula)
Recent Colloquia
Recent Talks
