January 10, 16:30 hr: Dr. Jacques M. BECKERS
Abstract Revisit a paper I wrote in 1977 on the spectral line shifts in sunspot umbra observed on an absolute wavelength scale. In that paper I examined not only the motions inside sunspots but also the then already known issues associated with the "Limb Effect" in the spectrum of the quiet photosphere (observed in 1907 by Halm). These issues include what is now known as the "convective blueshift" and the Einstein gravitational redshift. In sunspots things behave quite differently. In my talk I will compare sunspot and quiet photosphere spectral line shifts from the modern day perspective. Although recent modeling of solar surface convection has resulted in an unambiguous interpretation of the quiet photosphere line profile and shift observations, the 1977 paper appears to report the only work done on the topic in sunspots, both covering observations and interpretation. The observational technique developed for that research has led directly to one of the two spectroscopic techniques used by many exosolar "planet hunters".
January 18, 16:30 hr: Dr. Katherine BLUNDELL
Abstract Jets in microquasars evolve much more rapidly than do the jets of extragalactic quasars and so offer much potential for learning about jet physics. I will present new results on two relativistic radio jet sources in the Galaxy, SS433 and Cygnus X-3, and show how after properly accounting for the effects of light-travel time they reveal important behaviour in their jet evolution.
January 20, 16:30 hr: Dr. Jean-Pierre LUMINET
Abstract What is the shape of the Universe? Is it curved or flat, finite or infinite ? Is space " wraparound " to create ghost images of faraway cosmic sources? The lecture will introduce cosmic topology and review the most promising techniques (cosmic crystallography, pairs of correlated circles in the cosmic microwave background radiation) for detecting the topological signatures of space within the next decade. I will discuss more particularly the recent proposal by Luminet et al. of a finite, positively curved, dodecahedral space as the best fit model for explaining the power spectrum of temperature anisotropies as observed by WMAP satellite.
January 24, 16:30 hr: Dr. Angela BRAGAGLIA
Abstract We have a long term project aimed at studying the Galactic disk properties using (old) Open Clusters as tracers. We are particularly interested in the Galactic chemical evolution history, and OC's permit to probe the whole lifetime of the MW disk, up to about 10 Gyr ago. One important question that still needs to be answered regards the evolution of the chemical abundance gradients in the Galactic disk: the (possible) change in slope will help choosing between chemical evolution models, which predict different scenarios for early epochs. One problem encountered in using OC's to this end, is the inhomogeneity in OC's parameters (distance, age, and metal abundance) found in literature; not only absolute values, but also the ranking can be uncertain. For this reason, we are building a large sample of clusters (at least 30) for which age, distance and metallicity are all derived in a homogeneous way, from accurate photometry coupled with the synthetic colour-magnitude diagrams technique, and high resolution spectroscopy and fine abundance analysis. Results on about half our sample will be presented.
January 26, 14:00 hr: Dr. Jean-Pierre LUMINET
Abstract Through the analysis of works of various artists and creative scientists, such as Plato, Durer, Van Gogh, Kepler, Einstein, I will show how the process of creation in science as well as in art, rests on aesthetical principles such as symmetry, beauty, conciseness and emotional approach of the world.
January 28, 11:30 hr: Dr. James HARVIN
Abstract The application of cross-correlation techniques and Doppler tomography to the available set of IUE high-dispersion UV spectra and a set of ground-based He I lambda 6678 profiles has produced the first double-lined spectroscopic orbital elements for the central binary in the massive triple star delta Orionis A. The orbital elements for the primary agree well with previous results and confirm the apsidal advance of periastron with a period of 224.5 Â± 4.5 y. The tomographic reconstructions of the primary and secondary stars' spectra confirm the O9.5 II classification of the primary and indicate a B0.5 III type for the secondary.
The central binary in delta Orionis A also undergoes eclipses. Using the spectroscopic elements above to make a constrained fit of the Hipparcos light curve limits the inclination of the central binary's orbit to a range 67 to 77 degrees. However, this presents a problem. The resulting masses of the components are a primary mass between 11.2 and 9.4 solar masses and a secondary mass between 5.6 and 4.8 solar masses. The most likely component masses are 10.3 and 5.1 solar masses, respectively, which leads to the conclusion that both of these stars have masses which are between one-half and one-third of the expected values from evolution theory for stars of their MK types and luminosities.
February 3, 16:30 hr: Dr. Kazushi IWASAWA
Abstract Relativistically distorted X-ray iron emission lines, found in some active galaxies, are considered to be a useful probe to the accretion flow and the strong spacetime curvature at the immediate surrounding of a black hole. I present our finding of systematic, energy and flux variations of a transient iron emission feature observed in the Seyfert galaxy NGC3516 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 (~10 gravitational radius) around a black hole. This interpretation, involving modulating relativistic effects, and its implications for the black hole mass will be discussed.
February 16, 16:30 hr: Dr. Gian Paolo TOZZI
Abstract Comets are supposed to have played a crucial role in the development of terrestrial life by delivering organic matter to the primordial Earth. Nowadays complex organic molecules are "routinely" detected in comets by their emissions in the near-IR (3-4 micron) and in the radio (mm) regions. However, a large part of organic matter may be under the form of a solid or embedded on dust particles. This kind of organic matter is very difficult to detect because it emits only in wide spectroscopic bands and sublimates rapidly under the effect of solar radiation. Indeed the presence of organic solids was found for the first time by the fly-by missions to Halley's comet. Recently, using ESO telescopes, solid organics have been detected in a couple of comets. In the talk I will review the study of organic matter in comets and I'll describe the technique used to detect the solid organics. Possible prospectives in this field will also be illustrated.
February 22, 16:30 hr: Dr. Mara SALVATO
Abstract Novadays is accepted that AGN activity is just a (maybe recurrent) phase in the life of all galaxies. Nevertheless it is still unclear which is the triggering event of such activity. Many authors tried to establish weather it is a matter of environment or morphology of the host galaxies. The contradictory results obtained so far may be due to biases in the sample definition or in different criteria used in the selection. In this talk I will present the results I obtained using a complete, local (z<0.1) and X-ray flux limited sample of Seyfert 1 galaxies.
February 24, 11:00 hr: Claus MADSEN
Abstract Since its early days ESO has undergone an impressive development and has emerged as one of the leading research organisations for astronomy in the world. The technical and scientific achievements of the organisation as well as its ambitious project portfolio also entails a role for ESO in the public sphere, covering a wide range of issues and activities, from its involvement in public awareness of science activities and educational outreach to complex science policy matters. The talk will discuss the public face of ESO in the context of sweeping changes in Europe and in particular, lay out the role and the programme of the ESO Public Affairs Department for the time to come.
February 25, 16:30 hr: Dr. Roberto MIGNANI
Abstract After the identification of the Crab Pulsar, back in 1969, about a dozen of Isolated Neutron Stars (INSs) have been detected in the optical. This has opened a new, important, channel in the multi-wavelength studies of these intriguing obejcts.
In many cases optical observations have played a key role for the general understanding of neutron stars properties as well as for unveiling their interactions with the ISM.
In this talk the state of the art of optical studies of INSs and their Pulsar Wind Nebulae (PWNe) is reviewed together with recent results obtained from HST and VLT observations.
March 1, 16:30 hr: Dr. Federico GONZALEZ
Abstract This seminar reviews the various techniques developed in the last years for the analysis of composite stellar spectra. The main aim is to measured accurate radial velocities of double-lined spectroscopic binaries and/or perform a detailed spectral analysis of their individual components.
Finally, a new method recently developed at CASLEO is presented and illustrated by analyzing different binary systems, including blended spectra and low luminosity-ratio spectroscopic binaries.
March 9, 16:30 hr: Dr. Beate STELZER
Abstract Magnetic activity, manifest in chromospheric and coronal emission, is an ubiquituous phenomenon on late-type stars. The essential ingredients driving a stellar dynamo are rotation and convection. In particular, solar-like dynamos operate in the overshoot layer between a radiative core and a convective envelope. Consequently, fully radiative intermediate-mass stars should show no activity phenomena, and fully convective very low-mass stars may show activity but originating in a different type of dynamo.
X-ray emission is an observational tool to examine the nature of activity in these critical regimes. I discuss recent observations with XMM-Newton and Chandra carried out to (A) investigate the mysterious X-ray emission from intermediate-mass stars -- believed to be absent but frequently observed and attributed to (unknown) late-type companions; a multi-wavelength approach involving X-ray and IR imaging and spectroscopy is used to test the companion hypothesis. (B) understand the nature of the dynamo operating in fully convective stars and brown dwarfs; targets have been selected to sample the parameter space of age, effective temperature, and mass to constrain the influence of these quantities.
March 11, 12:00 hr: Dr. Mark GIELES
Abstract Star clusters are ideal chronometers to derive the star formation history of galaxies. When deriving fundamental parameters such as the ages and masses of clusters in a galaxy, the cluster formation history and the disruption of clusters can be studied. In this talk I focus on the cluster population of M51 and compare the ages and masses of more than 1000 clusters, as derived from HST broad band photometry, with analytical models based on different cluster formation histories and disruption mechanisms. The clusters in M51 live very short when compared to other galaxies and to what is expected from N-body models. The luminosity function (LF) of clusters is a powerful tool to study a population of clusters as a whole. In this talk I show how the LF can be used to derive fundamental parameters for the clusters in that host galaxy.
March 23, 16:30 hr: Dr. Håkon DAHLE
Abstract The abundance of massive clusters of galaxies is a sensitive probe of how cosmic structures have grown throughout the history of the universe. This can provide constraints on cosmological parameters that are complementary to the constraints obtained e.g. from the cosmic microwave background or from high-redshift supernovae. Any effort to do precision cosmology with clusters requires careful calibration of the scaling relations between various observables of the baryonic component of the cluster and the total cluster mass, which is dominated by non-baryonic dark matter. I will present results using weak gravitational lensing to determine these relations and provide new constraints on the cosmological parameters governing structure growth in the universe.
March 28, 16:30 hr: Dr. Nuno SANTOS
Abstract Radial velocity surveys have revealed up to now about 115 extra-solar planets, among which a few multi-planetary systems. The discovered planets present a wide variety of orbital elements and masses, which are raising many problems and questions regarding the processes involved in their formation. The statistical analysis of the distributions of orbital elements, planetary masses, and relations between these, is however already giving some strong constraints on the formation of the planetary systems. Furthermore, the study of the planet host stars has revealed the crucial role of the stellar metallicity on the giant planet formation. In this talk we will review the current status of the research on this subject.
April 4, 16:30 hr: Dr. Natalia DRAKE
Abstract The lithium problem in chemically peculiar stars is a subject of numerous discussions. The proper identification of the 6708 A feature as a Li I resonance line was recently put in doubt. Using a large sample of high resolution spectra of CP stars obtained with different telescopes, we carried out a thorough analysis of the spectral regions near both lithium lines: the resonance Li I doublet at 6708 A and the secondary Li I line at 6104 A. Special attention was given to identification of blending lines, especially of rare earth elements. The simultaneous analysis of both regions permitted us to confirm high Li abundance in some magnetic Ap stars. However, the source of high Li abundance is still a challenge for any theory. A search for correlations between Li abundance and physical parameters of Ap stars, such as effective temperature, surface gravity, rotation velocity, abundance of rare earth elements and magnetic field strength is now being carried out. We present also the results of spectral monitoring of two Ap stars, HD 3980 and HD 83368, showing strong variations of position and intensity of the Li I resonance line. In addition, some results of Doppler Imaging will be presented. Knowledge of the abundance distribution of elements on the surface of CP stars can provide important information on microscopic diffusion in the presence of magnetic fields.
April 6, 16:30 hr: Dr. Danielle ALLOIN
Abstract In this presentation, I shall review an ensemble of new results obtained in collaboration with Emmanuel Galliano and co-Is. The general framework of the study will be given, while then, the specific cases on NGC1365, NGC1808 and NGC1068 will be detailed. The populations of embedded star clusters discovered around NGC1365 and NGC1808 will be reported on, together with their intrinsic properties inferred from modeling. The potential of analyses in the mid-infrared will be highlighted and recent SV data obtained with VISIR on the central region of NGC1068 will be shown. The study of extragalactic deeply embedded star clusters is turning into an exciting new field of research: I shall summarize the advances made so far and mention some prospective areas.
April 12, 11:30 hr: Dr. Olivier TITAUD and Dr. Axel OSSES
Abstract The transfer theory studies the propagation of a radiation field in a medium which contains heterogeneities. These heterogeneities can absorb, emit or diffuse light. These particles can constitute a gas or a plasma (electrons, ions, atoms, molecules) or macroscopic particles (macromolecules, drops, grains, etc ...). We can find applications to this theory in different areas, namely in Extern Geophysics (meteorology, ocean optics ...), in Nuclear Physics , in Physics Chemistry, in Biology and Medicine, and, finally, in Astrophysics. The specific intensity is the main magnitude of the transfer theory: it measures the total of energy carried by the field throughout an elementary surface, in an elementary direction cone and in an elementary interval of frequencies. It verifies the transfer equation which describes the propagation of energy carried by a radiation in a given direction and at a given frequency. This equation is an integro-differential one: the specific intensity is derivated with respect to the position variable but it is integrated with respect with the direction variables. By mean of a change of variable, it can be expressed as a weakly singular integral equation. The aim of this talk is to present an numerical method to solve the transfer equation which arises in a simplified model of stellar atmosphere where some geometrical and physical hypothesis are done. This method is based on Finite Rank Approximations of integral operators (FRA methods) like projection methods or product integration methods. The transfer stage is the more critical one in the resolution of the global problem of the atmosphere modelling because it is intrinsically difficult and the Transfer Equation must be solved up to 100000 times. On the first hand, it is of importance to know what is the quality of the approximate solution a numerical method gives and that is why I will present quickly the error analysis of the FRA method. On the second hand, a numerical code of radiative transfer for a such application must be very quick. I will present some algorithms of refinement schemes and some tricks to reduce the computation costs in order to speed up its resolution. Numerical experiments and some references will be given all along the talk.
April 6, 16:30 hr: Dr. Felix MIRABEL
Abstract I will review the discoveries of microquasars and their impact in our understanding of black holes in the universe (stellar black hole binaries, gamma-ray-bursts and Active Galactic Nuclei).
April 27, 11:30 hr: Dr. Martern VAN KERKWIJK
Abstract We still have little clue how stars are formed. Particularly puzzling is the existence of stars in very close binaries: during the pre-main-sequence phase these stars would have been inside each other. So, how can they form? One hypothesis is that they in fact formed further apart, but were brought in closer after formation, by gravitational interaction with a third member of the system. This hypothesis makes a clear prediction, that all close binaries are members of triple (or higher-order) systems. I will describe tests of this prediction on the closest possible systems, the contact binaries.
April 27, 16:30 hr: Dr. David BARRADO
Abstract One of the most interesting Star Forming Regions is associated to the O8III star $lambda$ Orionis (at 340 pc), the head of Orion. It includes several distinct associations (Collinder 69, Barnard 30 and 35, LDN 1588 and 1603, among others). The Lambda Orionis SFR (LOSFR) will become, due to its properties (morphology, distance, reddening, size), a cornerstone in the field of star formation, and will help us to understand the role of the environment in the Initial Mass Function, disk evolution (from Class I to Class II and III --Classical and Weak-line TTauri--), and the formation of brown dwarfs.
In this talk I will focus on Collinder 69, the central cluster, and Barnard 35. I will review our recent analysis of optical and near infrared ground based photometry, in combination with Spitzer data, taken with IRAC at 3.6-8.0 mu and with MIPS at 24 mu. These surveys have reveal a numerous population of low mass stars and brown dwarfs, with and without IR excesses due to circun(sub)stellar disks. We have also collected low- and medium resolution spectra of our candidate members, deriving Halpha emission and lithium abundances, and investigated the variability of part of them by monitoring both in the optical and in the near infrared. In the case of Collinder 69, all this wealth of data has been used to derive a Initial Mass Function covering the 50-0.02 M(sun) mass range.
May 6, 12:00 hr: Dr.Ansgar GAEDKE
Abstract We determined the proper motion and multiplicity of young brown dwarfs and brown dwarf candidates in the Chamaeleon I star-forming region. The aim is to find kinematic evidences for the formation of these substellar objects.
Therefore we used absolute and relative astrometry with epoch differences of about 14-17 years. We compared the proper motions of our sample with those of T Tauri stars in Chamaeleon, and they are in the same range.
We also determined the galactic velocities of our sample. One object shows a significant higher velocity compared to the others and thus might be a candidate for so called 'ejected embryos'. We found no evidence for the formation by photoionization of protostellar cores due to nearby hot stars.
Around the substellar objects in Chamaeleon I 16 companion candidates were investigated by astrometry for companionship. One of these objects might be a real companion, what is also supported by radial velocity variation of the primary.
May 25, 16:30 hr: Dr. Tom MARSH
Abstract I will describe the high-speed, multi-band CCD camera ULTRACAM and some of the programs that have been undertaken with it. These include precise eclipse measurements to test models of angular momentum loss in close binary stars, simultaneous X-ray/optical 'echo' observations of X-ray binaries, the detection of pulsars, multi-colour asteroseismological studies and an attempt to detect Kuiper Belt objects through occultations. If possible, I hope also to discuss results from the first run of ULTRACAM as a visiting instrument on the VLT during May 2005.
May 30, 16:30 hr: Dr. Roberto MIGNANI
Abstract Magnetars are a supposedly new class of astrophysical objects discovered at the end of 70s through high energy observations. To date, about a dozen of Magnetars, or candidate such, are known between our Galaxy and the Magellanic Clouds. In this talk, I will review the discovery of Magnetars, their observations at different wavelengths and their phenomenologies. Recent discoveries of Magnetars counterparts in the IR and their theoretical implications are also discussed.
June 1, 16:30 hr: Dr. Jorge MELNICK
Abstract There are several Domes in the Antarctic plateau that seem to have the ideal conditions for optical and IR astronomy. The most developed of these, Dome-C, hosts the French-Italian Concordia station is being tested at this very moment for the particular conditions relevant to 2-4m class optical-IR telescopes: seeing, adaptive optics parameters (theta-not and tau-not), backgrounds, etc.
I will present a synoptic view about what is currently known about Dome-C, and about the plans to install telescopes there.
June 6, 16:30 hr: Dr. M.S. Nanda KUMAR
Abstract I report on the discovery of 54 embedded clusters around 217 massive protostellar candidates. The embedded clusters are identified as stellar surface density enhancements in the 2micron All Sky Survey (2MASS) data. We analyze our sample by estimating for each cluster the mass, the morphological type as centrally symmetric or hierarchical, the photometric properties of the members and their average extinction, and we identify 2micron counterparts to the 1.2 mm continuum peaks that are thought to identify the massive star precursors themselves. We construct an Embedded Cluster Mass Distribution Function (ECMDF) that agrees well with the ECMDF of the embedded clusters within 2Kpc. The presence of embedded clusters around a significant sample of massive star precursors suggests that in an embedded cluster, the massive stars form one-half to one Myrs after the first generation of low mass stars are born. This age difference is consistent with that predicted by the theory of massive star formation by continuous accretion in which the precursors to massive stars are zero age main sequence (ZAMS) intermediate mass stars that gain mass by accretion and evolve up the ZAMS line to become high mass stars. Finally, because the clusters are associated with very young precursors to massive stars they may represent an evolutionary stage prior to dynamical relaxation thus providing a neat laboratory to study cluster formation. I shall present some new results on ring shaped embedded clusters chosen from this sample which show striking resemblance to some numerical simulations.
June 9, 16:30 hr: Dr. Jean-Philippe BEAULIEU
Abstract There has been for more than 20 years a strong evidence from the observed flat rotation curves of spiral galaxies, that such galaxies (including our own) have extensive halos of dark matter. Paczynski suggested in 1986 that a population of MAssive Compact Halo Objects (MACHOs) making up the halo would be detectable by their gravitational microlensing influence on background stars. These events being extremely rare and millions of stars in the Large and Small Magellanic Clouds had to be monitored over several years. In the early 90s two large groups, the EROS and MACHO collaborations, entered the game. After the pioneering detections in 1993 (in those days they were compatible with a Halo fully made up of MACHOs), and years of data collection analysis and Monte Carlo simulations to estimate their detection efficiencies, the two experiments are releasing their final results. As of 2003, both experiments had two different points of view: because of the unknown stellar variability noise background, EROS published an upper limit of the MACHO content of the halo(20 % in the mass range 10^-7-1Mo) , whereas the MACHO collaboration suggests that their result can be understood as a signal of about 20% of the halo mass with a mass for the lenses in the range 0.2-0.9Mo. The results are compatible. However, now, using the complete final EROS dataset (1996-2003), stronger constraints can be given. The final EROS analysis will be presented. We will discuss the background noise of the experiment (phenomenon mimicking microlensing events), and conclude that the microlensing signal observed towards the Magellanic Clouds is a mixture of self lensing, disk lensing, poorly covered background supernovae, Be stars, ... There is no evidence for a contribution of MACHO in our galactic halo.
June 16, 16:30 hr: Daniel KUBAS
Abstract When the light of distant stars (sources) in the Galactic Bulge is bent by intervening compact objects such as stars or planets acting as lenses, an apparent change in brightness of the source star can be observed. By analyzing the lightcurves of these so called microlensing events, a large variety of interesting astrophysical questions can be studied. For example, theoretical stellar atmosphere models can be directly tested with observations using the enormous magnification/amplification factors that can occur in the course of such events and constraints on the Galactic abundance of extra-solar planets can be given for parameter spaces inaccessible to most other techniques. The talk will present the latest results of the PLANET (Probing Lensing ANomalies NETwork) campaign.
June 22, 16:30 hr: Dr. Eric PANTIN
Abstract VISIR is a recently installed Mid-Infrared instrument on UT3 (Melipal) of the VLT. Its commissioning phase was performed from June to August 2004. Since this time, lots of efforts have been put to include VISIR into standard VLT operations; in parallel we continued assessing its performances and limitations. I will review different aspects of VISIR : its design, capabilities, limitations and performances, data processing, tools associated.
Finally, I will illustrate VISIR potentialities by giving a taste of scientific results based on collected data during Science Verification and Guaranteed Observing Time campaigns.
June 28, 16:30 hr: Dr. Sylvain CHATY
Abstract Since its launch, the high-energy satellite INTEGRAL has revealed a new population of highly obscured binary sources hosting compact objects, likely constituted of neutron stars/black holes and early-type stars. These sources can only be revealed thanks to high energy or near-infrared observations, and I will show recent observations in the course of revealing the hidden nature of these sources. These sources are extremely useful in the understanding of the formation and evolution of such high-energy binary systems.
June 30, 16:30 hr: Drs. Heike RAUER, Hans-Ulrich KAEUFL and/or Hermann BOEHNHARDT
Abstract On July 4th, NASA's Deep Impact mission will reach its culminating point: the 370 kg 'impactor' part of the spacecraft - partly made of Chilean copper - will hit Comet Tempel 1 nucleus at a velocity of 10 km/s. A crater will be formed, possibly 200m wide and 30m deep, and materials will be ejected. Astronomers all around the world are on the watch: amongst them, Heike Rauer, at Paranal, and Hans-Ulrich Kaeufl, at La Silla. They will address such questions as: What is a comet? What do astronomers hope to learn from such a mission? What observations will be carried out at ESO?
July 11, 11:30 hr: Dr. Ray JAYAWARDHANA
Abstract Recent findings by our group and others provide compelling evidence that young sub-stellar objects undergo a T Tauri-like phase similar to that of low-mass stars, possibly suggesting a common formation mechanism. The supporting evidence includes infrared and millimeter observations of disk emission as well as high-resolution optical and infrared spectra with signatures of accretion. Moreover, there are now indications of disk locking and outflows/winds in objects close to or below the sub-stellar limit, further strengthening the analogy with T Tauri stars. The timescale for (inner) disk evolution does not appear to be vastly different between the stellar and sub-stellar regimes. I will review recent findings, present new results --including the first comprehensive study of emission line variability of an accreting brown dwarf-- and discuss prospects for the near future.
July 18, 16:30 hr: Dr. Gerhard SCHWEHM
Abstract I will give an overview of where we are, the Cosmic Vision exercise proper, and an outlook on the implementation.
July 20, 16:30 hr: Dr. Romain PETROV
Abstract We describe the VLTI instrument AMBER, its main science programs, characteristics and measures. We present its status and performances around the middle of its commissioning and we discuss the preliminary results on emission line hot massive stars such as gamma Velorum, Eta Car or the Be star kappa CMa.
July 22, 11:30 hr: Christophe COURONNE and Dr. Cédric FOELLMI
Abstract PyQuick is a Python/PyRAF quick-look software currenly installed in La Silla at the NTT for EMMI. It allows to reduce easily and flawlessly any EMMI long-slit and echelle spectrum. Its current infrastructure however does not allow easily to extend it to other spectrographs. This is the work that has been done by Christophe Couronne. We will therefore present the new version: PyQuick 2.0 and its functionalities. A demo will be done on some VLT/La Silla data. Since PyQuick 2.0 has the potentiality to become a very efficient quick-look, approaching pipeline capabilities, we will conclude by a discussion on the interest of such software, and its potential uses by the ESO astronomers and visitors.
July 25, 11:30 hr: Dr. Florentin MILLOUR
Abstract Since the first commissionning run of AMBER, we began to compare what was really observed on the sky to what was expected by simulations and laboratory experiments on the instrument. The unexpected differences were the beginning of discoveries of the VLTI infrastructure vibrations and thinking about different data processing techniques to get partly rid of these fringe-killing problems. I will present here the general scheme of the AMBER data processing and also some techniques we use that are mostly non sensible to the VLTI vibrations.
July 26, 16:30 hr: Dr. Margrethe WOLD
Abstract We present a high resolution [NeII]12.8 micron spectrum, and a [NeII] narrow-band image, of the central kpc of NGC7582. The data show the structure and the rotation of the circum-nuclear star forming disk at a diffraction limited resolution of 0.4 arcsec (~40 pc), allowing us to probe the dynamics and the rotation of the gas close to the black hole.
July 27, 16:30 hr: Dr. Leonardo PELLIZZA
Abstract The availability of large, precise samples of pulsar proper motions triggered a lot of research regarding the kinematics of these objects. These studies were mainly aimed at finding pulsar-supernova remnant associations, determining pulsar birth velocity and kick distributions and establishing the pulsar progenitor region in the galaxy. Nevertheless, the unavailability of pulsar radial velocities (and consequently of the 3D velocity vectors) posess some limits to these studies. Recently, the discovery and high resolution imaging of several bow shock nebulae around pulsars opened a possibility of overcoming these limits by inferring the pulsar directions of motion (and hence their radial velocities) from the inclination angle of their bow shocks. In this talk I'll present the first results obtained from this technique and discuss the new insights in pulsar birth properties obtained from them.
July 29, 16:30 hr: Dr. Nicola MASETTI
Abstract One main objective of the INTEGRAL mission is a regular survey of the Galactic Plane complemented by a deep exposure of the Galactic Centre. The unique imaging capability of the IBIS instrument onboard INTEGRAL allows detecting hard X-ray sources with localization accuracy of 2-3 arcmin permitting, for the first time, to resolve crowded regions such as the Galactic Centre and the spiral arms. In the 1st IBIS survey 123 sources between 20 and 100 keV were detected, 28 of which (i.e. about 23% of the sample) have no obvious conterpart at other wavelengths and therefore cannot yet be associated with any known class of high-energy emitting objects. Although the cross-correlation with catalogues or surveys in other bands (especially soft X-rays, optical and radio) is of invaluable help in pinpointing the putative optical candidates, only accurate optical spectroscopy can confirm the association and reveal the nature of the object. Following this approach, I will present the status of the optical campaign, performed by our IBIS Survey group, on the determination of the true nature of the still unidentified hard X-ray sources.
August 1, 16:30 hr: Dr. Sperello DI SEREGO ALIGHIERI
Abstract In the 3D space which has as coordinates the effective radius R_e (in log), the velocity dispersion (in log), and the average surface brightness within R_e (in mag/arcsec2) early-type galaxies set on a plane, called the Fundamental Plane (FP). This interesting property has been known for almost 20 years, but its reasons are not yet completely understood. Using VLT spectroscopy and HST imaging of an almost complete sample of 18 early-type galaxies with 0.88<z<1.3 selected from the K20 survey, we study the FP, the Faber--Jackson and the Kormendy relations at z ~ 1, and compare them with the local ones. The FP at z~1 keeps a remarkably small scatter, and shows both an offset and a rotation, which we interpret in terms of evolution of the mass--to--light ratio, and possibly of the size. We show evidence that the evolution rate depends on galaxy mass, being faster for less massive galaxies. We discuss the possible factors driving the evolution of spheroids and compare our results with the predictions of the hierachical models of galaxy formation.
August 3, 16:30 hr: Dr. Christophe DUMAS
Abstract Yepun is now operating two instruments (NACO and SINFONI) equipped with adaptive optics, making this telescope the sharpest eye on Earth to look at the sky. SINFONI is an integral-field spectrograph working in the near-infrared. It's been installed on Yepun since June 2004 and was offered for general observing proposals starting period 75. In this talk, I will describe the observational capabilities of the
instrument and will review the first science results obtained.
August 5, 16:30 hr: Dr. Brett GLADMAN
Abstract Since 2003, the 1-degree FOV Megaprime mosaic has been acquiring observations along the ecliptic plane to perform discovery and tracking observations of trans-neptunian objects. I will describe the survey strategy, which is heavily influenced by the desire to have a well-characterized survey with detections biases sufficiently well understood that a survey simulator can test a theoretical model underlying structure of the Kuiper Belt against the observations, something which has been impossible with the currently available data. The first discoveries of this survey are just now arriving at the point where their orbits are well-determined. I will show the analysis of the limited 2002 pre-survey acquired using the same strategy as the ecliptic plane survey.
August 10, 16:30 hr: Dr. Julia SCHARWÄCHTER
Abstract The hypothesis that ultra-luminous infrared galaxies (ULIRGs) and quasi-stellar objects (QSOs) represent successive stages of a merger-driven evolution (Sanders et al. 1988) is still a matter of debate. As putative transition objects between the ULIRG- and the QSO-stage, I Zw 1 and 3C 48 play an interesting role for testing the evolutionary scenario in a case study approach. I will present our case studies of I Zw 1 and 3C 48, which comprise data from near-infrared imaging and spectroscopy with ISAAC, from millimeter line- and continuum-observations with the BIMA millimeter interferometer and the Plateau de Bure interferometer, and from numerical multi-particle simulations. A particular aim is to clarify the merger histories of the two QSO host galaxies, since galaxy mergers are the prime requisite of the evolutionary scenario.
August 23, 16:30 hr: Dr. Kim-Vy TRAN
Abstract I summarize results from our multi-wavelength studies of two rich galaxy clusters at z=0.59 & 0.83, and a unique protocluster at z=0.37. Using wide-field imaging from HST, extensive spectroscopy from the VLT and Keck, and deep X-ray imaging from Chandra, I illustrate the important roles galaxy accretion and galaxy-galaxy merging play in cluster assembly and early-type formation. Combining our results with studies at lower redshifts enables us to better trace the lineage of early-type galaxies in nearby clusters such as Coma.
August 24, 16:30 hr: Dr. Katherine BLUNDELL
Abstract SS433 is the paradigmatic jet-producing microquasar in our Galaxy. It persistently ejects radio-emitting plasma at a speed of 0.26c, along a direction which precesses every 162 days. I will present new results on the mass loss from this object via its jets, and also via its wind, and its influence on its surroundings.
September 1, 16:30 hr: Dr. Ricardo SCARPA
Abstract By the time, in 1937, the Swiss astronomer Zwicky measured the velocity dispersion of the Coma cluster of galaxies, astronomers somehow accepted the idea that the universe is filled by some kind of dark matter. After almost a century of investigations, we have learned two things about dark matter, (i) it has to be non-baryonic -- that is, made of something new that interact with normal matter only by gravitation-- and, (ii) that its effects are observed in stellar systems when and only when their internal acceleration of gravity falls below a fix value a0=1.210-8 cm s-2. Being completely decoupled dark and normal matter can mix in any ratio to form the objects we see in the universe, and indeed observations show the relative content of dark matter to vary dramatically from object to object. This is in open contrast with point (ii). In fact, there is no reason why normal and dark matter should conspire to mix in just the right way for the mass discrepancy to appear always below a fixed acceleration. This systematic, more than anything else, tells us we might be facing a failure of the law of gravity in the weak field limit rather then the effects of dark matter. Thus, in an attempt to avoid the need for dark matter many modifications of the law of gravity have been proposed in the past decades. The most successful - and the only one that survived observational tests - is the Modified Newtonian Dynamics. MOND posits a breakdown of Newton's law of gravity (or inertia) below a0, after which the dependence with distance became linear. Despite many attempts, MOND resisted stubbornly to be falsified as an alternative to dark matter and succeeds in explaining the properties of an impressively large number of objects without invoking the presence of non-baryonic dark matter. This suggests MOND is telling us something important about gravity in the weak field limit. In this talk, I will review the basics of MOND and its ability to explain observations without the need of dark matter.
September 7, 16:30 hr: Dr. Matt LEHNERT
Abstract I present the results of a systematic effort to understand the properties of high redshift Lyman break galaxies (z>5) using rest-frame UV spectroscopy and UV/optical imaging of large representative samples of Lyman Break galaxies at 4.8<5.8. Based on their rest-frame UV/optical spectral energy distributions, Ly-alpha emission, and sizes, I discuss the physical characteristics of such sources, the most fundamental of which are their masses, star formation rates and histories, and their likely contribution to the meta-galactic background at z~5 and early metal enrichment of the IGM.
September 9, 11:30 hr: Dr. Nicole NESVADBA
Abstract Recent cosmological simulations suggest that the feedback of powerful AGN at high redshift have played a major role in the evolution of the most massive galaxies we observe today. Thanks to the new generation of integral-field spectrographs, such as SINFONI, it is now possible to directly investigate the gas dynamics of high redshift galaxies. In the nebulosity around the powerful z=2.2 radio galaxy MRC1138-262, we find extreme gas kinematics and outflows that can plausibly only be attributed to efficient AGN feedback. I will present this pilot study, and discuss the cosmological consequences, if this source really is the "smoking gun" of AGN feedback. Intriguingly, the observed outflow naturally explains the oddities of massive galaxies in the local universe: Why are they "old, red, and dead"?
September 14, 16:30 hr: Dr. Maarten BAES
Abstract Interstellar dust is present in almost all types of galaxies. As a result of absorption, scattering and thermal emission, even modest amounts of interstellar dust can strongly affect the observed properties of galaxies. I present our Monte Carlo radiative transfer code SKIRT, designed to handle a variety of continuum radiative transfer problems in dusty galaxies. I will focus on the effects of dust on the observed
kinematics of galaxies. Our models show that dust can seriously complicate the detection of dark matter in elliptical galaxies from stellar kinematics and affect the shape of rotation curves of spiral galaxies.
September 15, 16:30 hr: Dr. Lars-Åke NYMAN
Abstract I will describe some of the projects done during science verification with APEX and show some of the results.
September 21, 16:30 hr: Dr. Werner WEISS
Abstract Space experiments and observatories were developed and run in the past by two quite diverse communities. Scientific communication between the parties was also rather limited to exchanging final results. This deficit of immediate collaboration has been changing significantly over the last decades, and even more recently with the availability of mini- and nanosatellites with high pointing stability.
In this context the examples of MOST (operational since 2003), COROT (to be launched in the summer of 2006) and BRITE (2007) will be discussed, and their achievements and potentials, in particular for asteroseismology will be addressed.
September 26, 16:30 hr: Dr. Dante MINNITI
Abstract Why search for extrasolar planets? What is the best way to do it? What fraction of stars have planetary systems? What kinds of extrasolar planets are there? What do the latest results mean? Where is the field going?
The simple answer to all these questions will be discussed.
September 28, 16:30 hr: Dr. Giovanni CARRARO
Abstract The third Quadrant of the Milky Way is receiving nowadays more and more attention. It is the direction of the Galaxy where the maximum warp is located and where the lively debated Canis Major/Argus overdensity has been recently discovered. Since long time it is known that a reddening window exists in this direction, which allows us to see very deep inside the disk. A few years ago we started a new observational campaign of open star clusters located in this part of the Galaxy with the aim to better trace the spiral arm development and to study the star formation history and the chemical evolution of the Milky Way up to the extreme disk periphery.
In my talk I shall highlight the status of this project, and discuss the use of open clusters to probe not only the properties of the Milky Way disk, but also the features and (non)existence of the Canis Major Galaxy.
October 5, 16:30 hr: Dr. Stefan GILLESSEN
Abstract We present the proposal for the infrared adaptive optics (AO) assisted, two-object, high throughput, multiple-beam-combiner GRAVITY for the VLTI. This instrument will be optimized for phase-referenced interferometric imaging and narrow-angle astrometry of faint, red objects. Following the scientific drivers, we analyze the VLTI infrastructure, and subsequently derive the requirements and concept for the optimum instrument. The analysis can be summarized with the need for highest sensitivity, phase referenced imaging and astrometry of two objects in the VLTI beam, and infrared wavefront-sensing. Consequently our proposed instrument allows the observations of faint, red objects with its internal infrared wavefront sensor, pushes the optical throughput by restricting observations to K-band at low and medium spectral resolution, and is fully enclosed in a cryostat for optimum background suppression and stability.
Our instrument will thus increase the sensitivity of the VLTI significantly beyond the present capabilities. With its two fibers per telescope beam, GRAVITY will not only allow the simultaneous observations of two objects, but will also push the astrometric accuracy for UTs to 10 micro-arcsec, and provide simultaneous astrometry for up to six baselines.
October 11, 15:30 hr: Dr. Dante MINNITI
Abstract Why search for extrasolar planets? What is the best way to do it? What fraction of stars have planetary systems? What kinds of extrasolar planets are there? What do the latest results mean? Where is the field going?
Following the introductory talk, here I will go into some detail in a few points, ending with some suggestions.
October 12, 16:30 hr: Dr. Nissim KANEKAR
Abstract Astrophysical studies of redshifted spectral lines provide a powerful probe of putative changes in fundamental constants across a large lookback time. After reviewing the current status of this field, I will describe a new technique to measure such changes, using multiple radio OH lines. This allows a simultaneous measurement of changes in the fine structure constant alpha, the proton g-factor, g_p, and the electron-proton mass ratio m_e/m_p, using OH lines from a single cosmologically distant object. This has the advantage that all lines arise in the same species, allowing a relatively clean comparison between the measured redshifts. I will also present the first detections of the 18cm OH satellite lines at cosmological distances, from the z = 0.25 source PKS 1413+135 and the z = 0.765 gravitational lens towards PMN J0134-0931. Remarkably, the 1720 MHz and 1620 MHz profiles are conjugate in both cases, with the sum of their optical depths consistent with noise; this implies that the lines arise in precisely the same gas. A comparison between the line redshifts can thus be used to test for any changes in the above constants, over a large fraction of the age of the Universe.
October 17, 16:30 hr: Dr. Alan WHITING
Abstract I present the results of a deep, all-sky search for previously overlooked Local Group dwarf galaxies. Candidate objects were produced by visual examination of ESO/SRC and POSS-II survey plates, followed up by imaging at CTIO and KPNO. Based on internal and external comparisons, we conclude that the Local Group census is essentially complete over that part of the sky not hidden by the Milky Way down to a surface brightness limit of about 26 magnitudes per square arc second. No more than one or two remain to be found, along with roughly a dozen behind Galactic obscuration.'
November 2, 16:30 hr: Dr. Lise CHRISTENSEN
Abstract Damped Lyman-alpha (DLA) lines seen in quasar spectra belong to neutral hydrogen clouds with high column densities and likely originate in galaxy disks. It is known that a large fraction of the neutral gas throughout the Universe is contained in DLAs, and hence they serve as reservoirs for formation of stars. Yet the galaxies in which the DLA clouds reside remain to a large degree undetected. Our current understanding of galaxy evolution at high redshifts is mostly based on galaxies selected from flux limited samples. However, this picture is largely incomplete, because at high redshifts most of the baryons in galaxies were in gas. I will present results of an integral field spectroscopic survey aimed towards detecting these absorption selected DLA galaxies in emission. The sample has 8 possible detection of Lyman alpha emission lines in a sample of 20 DLAs at 2<4. The Lya lines detected indicate that the galaxies in which the DLAs reside are large disks, but the star formation rates are not extreme. These emission lines from the DLA galaxies allow to place them in relation to other high redshift galaxies, and provide a complimentary picture of galaxy formation.
November 3, 16:30 hr: Dr. Georges MICHAUD
Abstract The atomic diffusion equation will be derived intuitively from first principles. The calculation of important coefficients will be sketched. Important time scales, scale heights and other physical properties will be described. Applications will be made to the Sun and Open Clusters.
November 7, 16:30 hr: Dr. Georges MICHAUD
Abstract A and B stars are those that show most prominently the effects of atomic diffusion. We will review the models proposed to explain those anomalies and propose steps to arrive at a satisfactory picture. It is when atmospheric phenomena play an important role that there are the larger uncertainties. In so far as the effects of accretion, mass loss, turbulence and meridional circulation may be neglected in their evolutionary models, the effects of atomic diffusion in them have now been calculated from first principles and will be presented. Abundance anomalies are not only superficial but extend over a significant fraction of the stellar radius.
November 9, 16:30 hr: Dr. Cesare CHIOSI
Abstract The advent of modern infrared astronomy has brought into evidence the role played by the interstellar dust in the subject of galaxy formation and evolution. Among other effects, dust absorbs the UV-optical light emitted by stars and returns it into the mid and far infrared (MIR and FIR). Therefore, to fully exploit modern data,
models of galactic population synthesis must include this important component. Existing literature models are limited to a few pioneer studies and need to be upgraded by taking into account recent advancements in the theory of stellar evolution and population synthesis. In this talk, I would describe the models of spectra of galaxies of different morphological type in presence of the interstellar dust that we developed in a series of two papers (Piovan, Tantalo & Chiosi, 2005a,b, MNRAS in press).
November 16, 16:30 hr: Dr. Andreas LUNDGREN
Abstract The barred spiral galaxy M83 (NGC5236) has been observed in the 12CO J=1-0 and J=2--1 millimetre lines with the Swedish-ESO Submillimetre Telescope (SEST). Using these data we have in detail investigated the
distribution, kinematics and star forming properties of the molecular gas in this galaxy. The pattern speed is determined from the residual velocity pattern, and the locations of various resonances will be discussed. A mass surface density map is presented, and compared to the critical density for star formation of an isothermal gaseous disk. The star formation rate (SFR) in the disk is estimated using data from various star formation tracers (FUV, B, Ha, FIR, and 6cm radio). The different SFR estimates agree well when corrections for extinctions, based on the total gas mass map, are made.
November 23, 16:30 hr: Dr. Michael DAHLEM
Abstract Understanding the rules governing disk-halo interactions is important to understand the chemical evolution of galaxies. Based on data of two L_* edge-on spiral galaxies we derived in 1995 a threshold value for the average energy input rate into the disk ISM to initiate disk-halo interactions and thereby the creation of gaseous halos. Now, 10 years later, we have new datasets available that allow us to search for further dependences of gaseous halos on the galaxies' properties. We find a clear trend of changing threshold energy input rates with total galaxy mass, explaining why some low-mass systems with relatively low star formation rates do have gaseous halos, while others with higher energy input rates don't.
November 24, 16:30 hr: Dr. Georges MICHAUD
Abstract Evolutionary models taking into account diffusive processes for all important atomic species (28) have been computed for stars of Pop II. I will briefly present them and will use them to discuss a number of properties of globular clusters (turnoff, horizontal branch, ages). Applications will be made to interpretation of results from WMAP on lithium.
November 28, 16:30 hr: Dr. Dante MINNITI
Abstract NGC 5128 - Centaurus A is the nearest giant elliptical galaxy. It contains a large system of globular clusters. It shows the closest spectacular past merger event. It is the most nearby radio galaxy with prominent jets. It also harbours the nearest supermassive black hole. In this lecture I will give an overview of the importance of recent research on this galaxy.
November 29, 15:30 hr: Prof. Stanley OWOCKI
Abstract The purpose of this mini-workshop is to confront recent results of the theory and observations (spectroscopy, interferometry) of circumstellar disks/structures around hot stars, mainly Be stars and magnetic stars and to stimulate related VLTI projects.
15:30 opening talk: Stan Owocki: Launching Hot-Star Disks
Abstract: Unlike the accretion disks of protostars or mass-exchange binary systems, the evolved and generally single or wide-binary status of hot-stars with disks seems to require that they must form from mass ejection (a.k.a. decretion) from the star itself. This talk will review recent efforts to develop dynamical models of such decretion disks, focusing on the role of rapid (perhaps near-critical) stellar rotation acting in combination with radiative driving, pulsation, and/or magnetic fields.
16:15 Swetlana Hubrig: Measurements of magnetic fields in early type stars (brief summary of observational results)
16:25 Christian Hummel: Circumstellar disk models used in interferometry (brief overview of the models used in interpretation of interferometric observations)
16:40 Discussion. Proposed topics:
- observational test of disk models
- how can models of circunstellar disks influence the interpretation of interferometric observations
- possibilities of VLTI to test the disk models, observational limits
- what model parameters should be tested from the theoretical point of view
November 30, 16:30 hr: Dr. Aleks SCHOLZ
Abstract Variability studies are an important tool to investigate key properties of stars and brown dwarfs. From photometric monitoring we are able to obtain information about rotation and magnetic activity, which are expected to change in the mass range below 0.3 solar masses, since these fully convective objects cannot host a solar-type dynamo. On the other hand, spectroscopic variability information can be used to obtain a detailed view on the accretion process in very young objects. In this talk, I will report about our observational efforts to use variability information to constrain rotation, activity, and accretion brown dwarfs and very low mass stars.
December 14, 16:30 hr: Prof. Stanley OWOCKI
Abstract One of the most fundamental tenets in astronomy is the Eddington limit, at which the radiative force from electron scattering equals the binding force of gravity. Luminous Blue Variable (LBV) stars observed near this limit often show evidence of unstable episodes of extensive mass loss, with the most extreme example being the 1840-60 giant eruption of eta Carinae, which resulted in ejection of ca. 10 solar masses in a bipolar outflow seen today as the Homunculus nebula. This talk will discuss how a super-Eddington luminosity can lead to such extreme mass loss, through continuum driving moderated by the "porosity" associated with structure arising from instabilities in the star's envelope and atmosphere. I will conclude with a brief discussion of the broad implications of such episodes of super-Eddington mass loss for massive star evolution, including progenitors of gamma-ray bursts, and even the first stars in the universe.
December 16, 11:45 hr: Marco GULLIEUSZIK
Abstract Heavy elements in the intergalactic medium (IGM) could have their origins in dwarf galaxies. Metal-enriched galactic winds are observed in dwarf galaxies, and one of the classical ways to explain the L-Z relation is through preferential loss of metals in less massive galaxies. If loss of metals does occur, its signature will be imprinted in the chemical evolution history of a galaxy, since the measured abundances will be lower than those predicted by closed-box models. In this framework, in the past years we have been carrying out a detailed study of the stellar content of LeoI through photometry, and we are adding another piece of information by presenting our measurements of its metallicity via the CaII triplet method. With this information we can build the star formation history and chemical evolution history of the galaxy, to be compared with models. This will tell us what is the extent of the contamination of the IGM by a dwarf galaxy like Leo I. Abundance determinations in these extragalactic systems have become possible only with the advent of 10-m class telescopes. Here we present new VLT/FORS2 data for red giant stars in Leo I.