January 7, 16:30 hr: Dr. Michael EDMUNDS
Abstract Interest in the formation and evolution of interstellar dust has been hightened recently with the possibility that some high - redshift galaxies may be completely shrouded in dust, and with worries about the effects of dust on supernova distance-scale estimates. But dust formation and evolution is a complicated process, and rather poorly understood - indeed, we may not even know what the main source is! I will present a rather elementary new model, based on consideration of the abundances of the heavy elements, that provides a useful conceptual framework for understanding the evolution of dust masses in galaxies. Future observational tests, particularly at mm wavelengths, will be suggested.
January 9, 16:30 hr:Dr. Maarten BAES
Abstract Hierarchical models of galaxy formation and various observational evidence suggest that elliptical galaxies are, like disk galaxies, embedded in massive dark matter halos. Stellar kinematics are considered the most important tracer for this dark halo at a few effective radii. Stellar kinematical evidence for dark halos has recently been presented for a number of nearby ellipticals. In these analyses, dust attenuation has not been taken into account, although it is now accepted that elliptical galaxies also contain a multi-component ISM, including a significant dust medium. Through absorption and scattering, this dust will affect all observables, including the observed kinematics. We constructed a set of dynamical models for elliptical galaxies, in which dust attenuation is included through a Monte Carlo technique. We find that a dust component, shallower than the stellar distribution and with an optical depth of unity, affects the observed kinematics significantly, in the way that it mimics the presence of a dark halo. We are hence faced with a new mass-dust degeneracy, which seriously complicates the interpretation of stellar kinematical evidence for dark halos. Taking dust into account in dynamical modelling procedures will reduce or may even eliminate the need for a dark halo at a few effective radii.
January 10, 16:30 hr: Dr. Michael EDMUNDS
Abstract In 1900 divers in the Mediteranian Sea recovered an extraordinary archaeological artefact. Investigations during the 20th century have shown it to be a complex astronomical calculating mechanism of gears, dating from around 70 BC, and more complicated that anything that was to come for a thousand years afterwards. What was it for? Who made it? Why? This non-technical talk will review what is known about the mechanism, setting it in the context of the astronomical culture of the first century BC, and attempting to answer these fundamental questions.
January 11, 16:30 hr: Dr. Michael EDMUNDS
Abstract The observation and interpretation of the abundances of the chemical elements is a major tool in understanding the formation and evolution of galaxies. This talk will review some elementary models which help us understand the influence of gas flows into, out of and around galaxies. The implications for (i) mass-metallicity relations, abundance gradients, stellar populations and (ii) the abundances of carbon, nitrogen and deuterium will be discussed.
January 23, 16:30 hr:Dr. Georges MEYLAN
Abstract Were all globular clusters born in the same way? Are some of them the former nuclei of tidally destroyed dwarf elliptical galaxies? Are some of them linked to left-over dark matter fragments, as predicted by modern models of hierarchical galaxy formation? We shall present recent results illustrating the complexity of the answers to the above questions.
February 6, 16:30 hr:Dr. Jean-Philippe BEAULIEU
Abstract PLANET, the Probing Lensing Anomaly NETwork, is an international collaboration that makes coordinated observations of on-going gravitational microlensing events from four sites in the southern hemisphere. Our primary goals are to detect or to put constraints on sub-stellar companions, and do spectroscopic observations during caustic crossing to probe stellar atmospheres. I will take you to a visit of the zoo of caustic crossing microlensing due to binary lenses, and in particular EROS-2000-BLG-5 : It is the first time that a caustic crossing has been observed in spectroscopy (TOO on FORS), and the first direct mass measurement of a binary lens microlensing. So far no planets has been discovered by microlensing. I will present the refutation of the different claims made recently. I will present the constraints of the frequency of Jupiter mass planets via microlensing based on the observations of 43 intensively monitored microlensing. Less than 33% of M-dwarfs in the Galactic bulge have Jupiter-mass companions between 1.5 and 4 AU.
February 13, 16:30 hr: Dr. Markus NIELBOCK
Abstract The observational technology in the (sub)millimetre regime of the electromagnetic spectrum is currently undergoing a development probably only similar to the revolutionary breakthrough in the optical waveband, provided by the CCDs in the 1980s. A new and technically unique bolometer array has been successfully comissioned at the SEST in June 2001 and a second season of observations has already been carried out between October and December 2001. The number of proposals, which lifted the SEST to ESO's telescope most asked for, clearly demonstrate the great need for such an instrument in the southern hemisphere. This raises great expectations for the coming large submillimetre projects like APEX and ALMA. This talk gives an overview on SIMBA's technical specifications and its capabilities. It outlines the procedure of a typical observation run and summarises the research fields, which SIMBA can be used for. Finally, a couple of images from recent measurement camapigns are presented, some of which have been kindly provided by visiting observers.
February 20, 16:30 hr:Dr. Chris MULLIS
Abstract In the ROSAT All-Sky Survey, a region of 80.7 square degrees around the north ecliptic pole (NEP) constitutes the deepest X-ray observation ever achieved of such a large, contiguous area. Here 445 unique sources are detected with fluxes measured at greater than 4 sigma significance. We have identified the physical nature of 443 (99.6%) of these sources through a comprehensive program of imaging and spectroscopy with primarily the UH 2.2m, CFHT 3.6m, and Keck-II 10m telescopes. The main constituents of the resulting catalog are active galactic nuclei (AGN; 49%), galactic stars (34%), and clusters of galaxies (14%). We have used the complete samples of extragalactic X-ray sources to examine the evolution and distribution of large-scale structure in the universe. Measurements of the cluster X-ray luminosity function and integrated counts show negative evolution in the cluster population at high redshift and high luminosity. Our X-ray analysis of a previously known supercluster at z=0.087 greatly improves our understanding of this structure - doubling its spatial extent and tripling the cluster/group membership. Also relevant to large-scale structure, and in particular cluster formation, is the discovery of a distant, filamentary cluster at z=0.81. Working beyond coherent structures, we have measured the degree of clustering in the ROSAT NEP data by calculating the two-point spatial correlation function for soft X-ray selected AGN.
February 25, 16:30hr: Dr. Stuart RYDER
Abstract The serendipitous discoveries of a handful of low-surface brightness galaxies, having few stars but enormous amounts of hydrogen gas, have led to concerns that optical telescopes may be showing us just the "tip of the iceberg". Hydrogen gas is important as it provides much of the raw material for star formation in galaxies. Until recently, a complete survey for hydrogen gas in our local Universe would have taken decades to complete with a single radio telescope. The advent of the Parkes Multibeam Receiver, with its array of 13 independent receivers, has at last made such a survey feasible. The three-year HI Parkes All-Sky Survey (HIPASS) has recently been completed, and will provide the first inventory of all galaxy-sized clumps of gas within 500 million light years. In this talk, I shall present some of the early results from HIPASS, and discuss a few sources which appear to have no optical galaxy counterpart at all.
February 26, 11:30 hr: Nathan SMITH
Abstract The Homunculus reflection nebula around eta Carinae provides the rare opportunity to observe the spectrum of a star from more than one direction. We can infer how stellar-wind emission and absorption line profiles vary as a function of latitude, after correcting for Doppler shifts caused by the nebula's expansion. HST/STIS spectra of the star and several positions along the major axis of the bipolar Homunculus Nebula show directly that eta Carinae has an aspherical and axisymmetric stellar wind. The results imply that eta Car has a higher mass flux toward the poles, perhaps resulting from equatorial gravity darkening on a rotating star. The bipolar stellar-wind geometry may imply that the Homunculus Nebula was formed by asymmetric ejection, rather than by an externally constrained outflow. Extreme variability in the wind structure during eta Car's 5.5 year cycle is also surprising, and has some implications for the role of a hypothetical companion star.
March 5, 16:30 hr: Dr. Henrique SCHMITT
Abstract The orientation of a black hole rotation axis relative to its host galaxy rotation axis is an important diagnostic for the structure of the accretion disk and the nuclear region of the galaxy. Since jets are believed to be launched perpendicular to accretion disks, and the gas which fuels the nucleus is expected to originate in the galaxy disk, or if new gas is added to the galaxy it will end up in the disk, the simplest picture suggests that jets should be perpendicular to galaxy disks. However, observations show that this assumption is wrong. I will talk about the results obtained for Seyfert and Radio galaxies, their implications for the structure of accretion disks and host galaxy disks, as well as for the processes responsible for feeding the nucleus.
March 8, 11:30 hr: Maria Rosa CIONI
Abstract Large scale surveys towards the Magellanic Clouds recently provided an extremely useful set of data to study the red giant stellar population. In particular the analysis of 1.3 and 0.3 million DENIS (I, J, Ks) sources towards the Large Magellanic Cloud and the Small Magellanic Cloud, respectively, has allowed us to investigate several important issues: the distance, the morphology, the variability and the spectral type of asymptotic giant branch stars. Similar studies are foreseen in other galaxies in the local group.
March 13, 11:30 hr: Alessandro PIZZELLA
Abstract Preliminary results of the spectroscopic observations of a sample of 4 bulge-dominated Low Surface Brightness galaxies are presented. We measured the stellar and gaseous kinematics along their major and minor axis. Such combined information will allow us to accurately investigate the dark matter content within their optical regions, providing further constraints on cosmological models.
March 19 16:30 hr: Dr. Luis Felipe RODRIGUEZ
Abstract It is well known that most main-sequence stars are in binary or multiple systems. However, the implications of this multiplicity in the very youngest, deeply embedded stellar systems is just beginning to be understood. I will discuss recent examples of such systems, that are detected at radio wavelengths as binary or multiple on scales below one arcsec. These systems include L1551 IRS5, SVS 13, YLW 15, and HH 111, all key sources in the study of young stars. The finding that these sources are binary or multiple leads to a reinterpretation of their parameters and brings new possibilities to our understanding of the star formation phenomenon.
March 22 11:30 hr: Daisuke KINOSHITA
Abstract Wide-field imaging with moderate depth was carried out using Subaru telescope with the prime focus camera ``Suprime-Cam'' to search for the existence of minor bodies beyond 50 AU from the Sun. Total 1.4 deg^2 around ecliptic covering 2 degrees in ecliptic latitude (-1 beta 1 deg) was searched down to the R-band limiting magnitude of m_R = 26.1. This survey area is larger than any previous works of comparable depth. 15 TNOs were detected, and 9 of them having semimajor axes 39 a 45 AU received provisional designation from MPC. But none of them has the orbit beyond 50 AU, and the upper limit of the surface density of distant object is 3.3 deg^-2 for the limiting magnitude of m_R =25.2 at 95% confidence level. The detection efficiency of our detection programme for slow moving object was measured using implanted artificial objects, and the derived surface density of TNO brighter than m_R = 25.25 is Sigma = 33.89 +/- 16.91 deg^-2. The cumulative luminosity function was fitted by the single power-law distribution, and the obtained slope was alpha = 0.65. We will report the absence of objects beyond 50 AU in our datasets and note the structure of the outer belt in our solar system.
April 3 16:30 hr: Dr. Patrick PETITJEAN
Abstract Absorption lines observed in the spectra of remote (high-redshift) quasars reveal gas located on the line of sight anywhere between us and the quasar. Any intervening object, as tenuous as a diffuse intergalactic cloud or as dense as a galactic disk, located by chance in front of the quasar, produces a recognizable absorption in the spectrum of the quasar.It is therefore possible to study the physical characteristics of the intergalactic medium (density, temperature, ionization-state, chemical composition) and their cosmological evolution. A coherent picture has emerged recently from the comparison of observations with the outputs of large-scale N-body numerical simulations in which the diffuse intergalactic gas traces the filamentary structures of the dark-matter. Most of the baryons at high redshift are in this diffuse gas which is therefore the reservoir for galaxy formation. One of the most interesting project for the next few years in this field is to reconstruct the 3D spatial distribution of the gas and its connection to galaxies.
April 10, 16:30 hr:Dr. Richard DURISEN
Abstract My collaborators and I have been using 2D and 3D numerical hydrodynamics techniques to study gravitational instabilities (GI's) in disks around young stars. There are three general scientific questions of interest to us: 1) Can GI's in disks produce permanent bound objects, like planets or brown dwarfs? 2) Under what circumstances do GI's play a role in producing mass transport in young stellar disks? 3) What are the observable consequences of GI's in disks? The discovery of massive gas giant planets around nearby solar-type stars strains the standard core-accretion theory for gas giant planet formation, because disks do not last long enough for this mechanism to operate. Alan Boss (Carnegie Institute of Washington) has recently suggested that GI's can form such objects directly in a few orbit periods during an early phase of disk evolution when the disk is still massive. My talk will review some of the reseearch on GI's over the last decade. The main contribution of my own research group has been to demonstrate that proper treatment of the thermal physics of the disk is critical for determinng the outcome of GI's. I will then address all three questions above. It is premature to draw definitive conclusions about formation of planets by GI's, but it is clear that they have distinctive observable consequences. We may soon know whether they occur in real disks.
April 11 16:30 hr:Dr. Sabine Mengel
Abstract Star clusters are seen in all types of galaxies, which suggests that star formation in the form of clusters is a very common phenomenon. One question, however, is what circumstances trigger the formation of star clusters, and how they evolve once they are formed. Especially the latter question is closely related to cluster masses, because the survival rate depends - amongst other parameters - on mass, concentration and the initial mass function of stars in the cluster. Dynamical mass estimates are less model dependent than photometric masses, therefore we obtained high resolution spectra (using ISAAC/Antu and UVES/Kueyen) to determine those of a handful of clusters in NGC 4038/39, where hundreds of young star clusters were formed during the ongoing galaxy merger. Our results suggest that the clusters have masses and concentrations comparable to globular clusters, but that the content of low mass stars varies between the clusters, which might lead to early disruption of those which are weighted towards high-mass stars.
April 24, 16:30 hr: Dr. Armen GYULDUDAGHIAN
Abstract As a result of PSSP surveys which were done by me and with my colleagues, many different kinds of young non-stable objects were found. For example:more than 100 cometary nebulae, about 100 HH objects, about 20 radial systems of dark globules et cet. The investigation of some of these objects was provided and interesting phenomena, like connection with IRAS point sources, water masers, et cet. were discovered.
May 6, 16:30 hr: Dr. Patrick PETITJEAN
Abstract Amongst absorption systems seen in the spectra of quasars, the so-called damped Lyman-alpha systems are characterized by a very large Hsci column density Hsci ga210^20cm-2, similar to what is usually seen through local spiral disks. Although the nature of these systems is still controversial, they are probably related at high redshift to proto-galaxies. In particular, the presence of heavy elements Z sim 1/10 ~ Z_odot and the redshift evolution of metallicity suggest ongoing star formation activity in these systems. We have searched for molecular hydrogen in a number of damped Lyman-alpha systems. I will review the outputs of the survey and important "by-products" like the measure of the temperature of the microwave background or the constraints on the variation with time of the fundamental constants.
May 8, 16:30 hr:Dr. Tom MILLAR
Abstract It has been known for about 20 years that interstellar molecules contain deuterium in abundances enhanced over the cosmic D/H ratio. This fractionation was interpreted, rather successfully, as due to low-temperature ion-neutral gas-phase reactions. In recent years, fractionation has been discovered in high-temperature gas and multiply deuterated molecules, most notably ND3, have been detected with enhancements of factors of up to 10^12 - large even by astronomical standards. In this talk, I shall describe some of the recent observations of deuterated molecules and their use in probing the physics and chemistry of low and high-mass star formation. Connections between interstellar and cometary D/H ratios will be mentioned briefly.
May 22, 16:30 hr:Dr. Riccardo SCARPA
Abstract An experiment suitable to test the law of gravitation down to the regime of acceleration typical of galaxies and relevant to test MOND is proposed. The experiment uses stars in the extreme periphery of globular clusters, which are dark matter free, as test particles immersed in such weak gravitational field. Results for a pilot project for stars in the globular cluster \oc\ show the stellar velocity dispersion remains basically constant at large radii rather than decrease monotonically. This behaviour of the velocity dispersion is difficult to explain within the limits of Newtonian dynamics, and suggests Newton's law of gravity may not be applicable to such acceleration regimes.
May 29, 11:30 hr:Dr. Sara SEAGER
Abstract There are more than 70 known extrasolar giant planets orbiting single sun-like stars. Characterizing the planet atmospheres is difficult because the planet-star contrast is many orders of magnitude and the planet-star systems cannot be resolved with existing instruments. A subset of the known extrasolar planets are the close-in extrasolar giant planets (CEGPs), an unpredicted class of planets that orbit their stars with very short periods (~4 days). Seven times closer to their parent stars than Mercury is to our sun, the CEGPs are hot thermally and potentially bright in reflected light. Thus their atmospheric signatures should be detectable in the combined light of the planet-star system, and many observational programs are underway to do this. The recent detection of sodium in the atmosphere of the one known transiting extrasolar planet has provided a first observational constraint. I will present theoretical spectra and light curves of CEGPS, and discuss what current and future observations will tell us about extrasolar planets.
June 12, 11:30 hr: Dr. Leonardo VANZI
Abstract Blue Dwarf Galaxies include the most metal deficient and less evolved galaxies known. For this reason they are unique laboratories to study the primordial star formation and their study can provide very important clues on the galaxy formation process. Traditionally these objects have been studied mostly in the optical and UV. However recent observations in the infrared have provided a few surprises. I will present the general properties of Blue Dwarf Galaxies in the Infra-Red focusing on few particularly interesting examples. These new results will show how Infra-Red observations can provide crucial information on Blue Dwarf Galaxies.
July 3, 16:30 hr: Dr. Gaspare LO CURTO
Abstract I will briefly overview the theoretical foundation of the predicted new state of matter called Quark Gluon Plasma (QGP) and focus on the experimental signatures and the techniques to detect it, from ultra-relativistic heavy ion collisions in large particle colliders to observations of isolated neutron stars. Recent results will be discussed.
July 23, 16:30 hr: Dr. Markus KISSLER-PATIG
Abstract Euro3D is a newly sponsored Research Training Network (RTN) of the European commission. The talk is meant as a very informal opportunity to inform you about this new RTN at ESO and how you can participate or profit from it (e.g. it will offer 10 postdoc position over the next 4 years). I will briefly introduce integral field spectroscopy, before giving an overview of the RTN and describing its goals.
July 24, 16:30 hr: Dr. Duncan FORBES
Abstract In the first part of my talk I will summarise the observational situation for extragalactic globular clusters, drawing on observations from the Keck and Hubble Space Telescopes. One reoccuring theme is the general similarity of the globular cluster systems of spiral and elliptical galaxies. In the second part I will present a model for globular cluster formation within the hierarchical picture of galaxy formation.
August 7, 16:30 hr: Dr. Bruno SICARDY
Abstract Disk dynamics has a wide field of application: from galaxies to planetary rings, passing by proto-planetary disks around young stars. We review some problems of ring dynamics: resonances, spiral waves, confinement, showing how they may have important application to the formation of planetary systems. We also review important progresses brought by high resolution imaging, from the ground (adaptive optics) or space, of rings and disks.
August 19, 16:30 hr:Dr. John DAVIES
Abstract It is almost 10 years since the first trans-Neptunian object was discovered. Since then it has become clear that this "Edgeworth-Kuiper Belt" is far more complicated, both dynamically and chemically, than anyone suspected. I will review the evidence for multiple dynamical populations (possibly indicating that what we see today is a fossil disk contaminated by material ejected from closer to the Sun)and for a diverse, possibly bimodal, distribution of surface properties which may or may not be corelated with orbital parameters.
August 21, 11:30 hr: Dr. Bruno SICARDY
Abstract Stellar occultations are a powerful tool to detect material around the jovian planets and comets, and probe upper atmospheres of planets and satellites at very high spatial resolution (a few km or less). We review some of these observations, like the discovery of Neptune's rings from ESO and CTIO, the probing of Titan atmosphere, or the detection of Chiron's coma. The dynamical consequences of these observations are discussed. The atmospheric levels scanned by stellar occultations range from 100 to 1 microbars in pressure. These rarefied regions of planetary stratosospheres exhibit unexpected dynamical activities, like breaking gravity waves, auroral heating, etc.. all effects which may be important in the energetic budget of these layers.
August 26, 16:30 hr:Dr. Alan WHITING
Abstract I investigate the kinematics of galaxies within 10 Megaparsecs of the Milky Way, using published distances and radial velocities. With respect to the average Hubble flow (isotropic or simple anisotropic), there is *NO* systematic relation between peculiar velocity dispersion and absolute magnitude over a range of at least 12 magnitudes; neither is there any apparent variation with galaxy type or between field and cluster members. It appears that either there is no relationship between light and mass on these scales, or the peculiar velocities are not produced by gravitational interaction. Galaxies with a high (positive) radial velocity have clearly been selected against, biasing the numerical results for local calculations.
August 28, 16:30 hr:Dr. Montse VILLAR-MARTIN
Abstract Extended Lya regions are a common feature of high redshift radio galaxies (z>2, HzRG) and quasars. Most morphological and kinematic studies are based on the high surface brightness regions. These are clumpy, irregular, often aligned with the radio axis and show extreme kinematics. I will present the results on our recent work on high S/N Keck spectroscopy of a sample of 11 HzRG. We find that in addition to the typical high surface brightness regions, giant low surface brightness Lya halos (LSBHs hereafter)are often detected, which present quiescent kinematics consistent with gravitational motions. Such quiescent LSBHs are important since they show the gas properties unaffected by kinematic perturbations. I will discuss the origin of such halos. They could be similar in nature to the giant gaseous envelopes of chemically enriched gas discovered around galaxies of a wide range of luminosity and morphological types in studies of absorption line systems. I will also discuss alternative possibilities.
September 2, 16:30 hr: Dr. Montse VILLAR-MARTIN
Abstract The study of Seyfert galaxies and low redshift radio galaxies has revealed extended emission line properties which in general are well explained in terms of an illumination model, in which the ambient gas is illuminated and photoionized by active galactic nuclei (AGN) in the cores of the galaxies. However, AGN illumination is not the whole story. Both morphological and kinematic studies show that strong interactions take place between the radio-emitting plasma and the emission-line gas in some active galaxies which influence their observed properties in a very important way. Such interactions seem to be more frequent at high redshifts. In my talk I will discuss the evidence for such interactions and their dramatic effects on the morphological, kinematic and ionization properties of the extended gas in low and high redshift active galaxies.
September 6, 11:30 hr: Dr. Bahram MOBASHER
Abstract Estimates of star formation rate (SFR) in the local Universe (0 z 1) are still uncertain. This is mostly due to biases in selecting samples of star-forming galaxies, uncertainties in corrections for dust extinction and astrophysics of different star formation diagnostics. The most serious problem is that using different star formation diagnostic, one gets different SFRs, even for the same objects. In this talk I will address these problems by comparing SFRs estimated from a number of independent indicators, applied on the same sample of galaxies. This is expected to minimise sources of bias in measuring SFRs. Potential of multi-waveband surveys,used in this study, for finding new classes of objects is also discussed.
September 6, 16:30 hr:Dr. Guenther EICHHORN
Abstract The Astronomy Digital Library: A world-wide collaboration to provide access to the astronomical literature. The Astrophysics Data System (ADS) is the search system of choice for Astronomers world-wide. The database contains almost 3 million records. In addition the ADS has over 2 million scanned article pages from about 280,000 articles, dating back as far as 1829. The ADS provides a search capability for the astronomical literature that is freely available world-wide. More than 10,000 users query the ADS regularly (10 or more times per month). The ADS is accessed from almost 100 countries. In order to improve access from different parts of the world , we maintain 9 mirror sites of the ADS in Brazil, Chile, China, England, France, Germany, India, Japan, and Russia.
September 11, 16:30 hr:Dr. Grzegorz PIETRZYNSKI
Abstract OGLE is a long term observational program started in 1992 with the initial goal to detect dark matter using microlensing events based on photometry of millions of stars in the densest regions on the sky. However, the OGLE survey resulted not only in the detection of hundreds of microlensing events but also provided accurate BVI photometry for millions of stars including hundred thousands of variable stars and about thousand star clusters in the Magellanic Clouds. In early 2001, a new detector - an eight chip 8192 x 8192 pixels CCD mosaic, was mounted on 1.3 m Warsaw telescope starting the third phase of the OGLE project. The data flow was increased by an order of magnitude, reaching about 300 million photometric measurements per night. Longer exposures with a better scale (0.23 pix/arcsec) and the implementation of a new data reduction pipeline based on the image subtracting method allows us to reach a much better photometric accuracy. I will briefly discuss the main scientific achievements obtained from the OGLE project including the first results from the OGLE III phase.
A long term observational project called ARAUCARIA has been recently started at the Universidad de Concepcion, with the main goal to check on the systematics and true capabilities of several stellar methods for distance measurement, the using basic strategy to apply a variety of such techniques on a common sample of galaxies with widely different environmental properties, and to compare the results. This should finally lead to a clear picture about the true capabilities of the different methods, and their dependence on environmental properties like metallicity and age. I shall present the first results of two parts of this project: an optical search for Cepheids, and infrared photometry of red clump stars in nearby galaxies.
September 23, 11:30 hr:Dr. Pierre KERVELLA
Abstract Installed at the heart of the VLT Interferometer, the VINCI commissioning instrument combines coherently the infrared light coming from two telescopes. After more than one year of operation, it is now possible to evaluate its performances and characteristics. This is all the more important as since period 70, VINCI is open to shared-risk observation proposals. In addition to a large number of laboratory measurements, more than 3000 on-sky observations have been recorded using VINCI, giving a wide database of valuable scientific data. I will present examples of results that were obtained from this archived data on the luminous star Eta Carinae, Cepheid variables and red dwarfs.
September 25, 16:30 hr:Dr. Celine PEROUX
Abstract Quasar absorbers constitute powerful observational tools to measure the cosmological evolution of the neutral gas and metals. At z3.5, 90% of the HI mass is in damped Ly-alpha systems (DLAs). But it has been suggested that at z>3.5, 45% of the HI lies in systems below the traditional DLA definition, in ``sub-DLAs'' with 1019 N(HI) 2 * 1020 cm^-2. We took advantage of the ESO-UVES archive quasar spectra to build a homogeneous sample of sub-DLAs. These data are used to measure the sub-DLA number density redshift evolution and to directly establish the column density distribution function down to N(HI) = 1019 cm^-2. Detailed metal abundance analyses of this class of absorbers, including a full treatment of the ionisation correction, are made. I will discuss how these new results affect the cosmological evolution of metals as traced by quasar absorbers.
October 9, 16:30 hr: Dr. Remi CABANAC
Abstract The technology of the liquid mirrors has now reached a level which make them an attractive alternative to traditional optical instruments in various fields. My talk will focus on technical aspects of the technology, on the use of liquid mirrors to LIDARs, astronomy and the future.
October 16, 16:30 hr: Dr. Marguerite PIERRE
Abstract The XMM-LSS is the largest medium X-ray survey to date. With a sensitivity of 5E-15 erg/s/cm2 it is designed to investigate the evolution of structures traced by clusters of galaxies out to a redshift of 1. This will provide cosmological constrains complementary to those given by CMB and supernova studies. It is associated with an extensive multi-wavelength follow-up (CFHLS, UKIDSS, VLA) and with several other space missions like SIRTF and Galex. We shall give an overview of the scientific applications of the entire project which not only involves cluster science but also, AGN, weak lensing, star formation as a function of environment, etc... We 'll make a demonstration of our cluster database - the only XMM serendipitous cluster sample. We hope this seminar will initiate fruitful discussions and further collaboration as ESO/Santiago and PUC are full members of the XMM-LSS consortium which involves 15 institutions in total.
October 18, 10:30 hr: Dr. Therese ENCRENAZ
Abstract Water is ubiquitous in the Universe and, in particular, in the solar system. We find it in comets, but also in the giant planets and their systems, and in the telluric planets. In the case of comets, H2O observations bring information about their formation temperature, through the measurement of their ortho/para ratio. In the case of the giant planets, the recent unexpected detection of stratospheric water vapor shows evidence for an external oxygen source, possibly connected to an interplanetary micrometeoritic flux. Saturn's rings and bare satellites are mostly made of water ice, as well as the Galilean satellites (apart from Io, too cose to Jupiter). In the case of Europa, an ocean of liquid water might exist under the surface, which leads to new perspectives for exobiology.
The measurement of the D/H ratio in water brings important constraints on formation mechanisms of solar-system objects. As an example, the D/H ratio in comets is significantly larger than the terrestrial one, which implies that the terrestrial water cannot come entirely from comets. In the case of terrestrial planets, the very large deuterium enrichment (especially in the case of Venus) is probably the signature of an early outgassing of the atmosphere, primarily rich in water as in the case of Mars. The history of the Martian atmosphere is especially fascinating. Several discoveries seem to indicate that Mars once had liquid water on its surface, and even probably a water ocean. Could life have appeared on Mars at that time, and if so, could we find fossil signatures of it? This will be a major challenge for the future space exploration of Mars.
Liquid water is also the key signature which will be searched for in the quest for extraterrestrial life outside the solar system. Only giant exoplanets can be now discovered with the presentinstrumental means, but terrestrial exoplanets should become detectable in the forthcoming years, especially with the COROT mission.
October 21, 16:30 hr:Dr. Andreas KORN
Abstract Latest efforts in wide-angle objective prism surveys for finding very metal-poor halo stars are presented. The HES (Hamburg-ESO survey) is pushing the limit deeper by substantially increasing the number of stars with metallicities below 1/1000th the metal content of the Sun. Apart from their identification, the analysis of such objects constitutes a major challenge. Conventional spectroscopic methods for deriving stellar parameters become inapplicable and/or produce results which are in disagreement with established standards.
I will review a set of tools developed by the cool-star group at the Observatory Munich (USM) which allows these stars to be tackled. Exciting results on newly identified stars will be given.
November 4, 11:30 hr:Dr. Tommy WIKLIND
Abstract The use of two different bands in the Rayleigh-Jeans part of the dust continuum spectral energy distribution as a redshift indicator of distant far infrared lumninous objects is discussed. Based on a sample of low redshift ULIRGs, including both pure starbursts and AGN dominated sources, it is shown that the shape of the FIR and submm SED is remarkably uniform. The flux ratio of two submm bands at 850 and 450 microns, is sensitive to the redshift of the source in the range 1 z 5. A comparison with submm flux ratios for a sample of high-z AGNs (gravitationally lensed) shows that this technique is accurate enough to allow a redshift determination to within 30%. With the advent of new submm telescopes and instruments, capable of operating up to 325 microns, such as APEX and ALMA, the use of submm flux ratios is foreseen to become a technique to quickly estimate the redshifts of large numbers of submm detected sources.
November 6, 16:30 hr:Dr. Marc SAUVAGE
Abstract With the advent of either sensitive space-born infrared cameras, or their high-resolution ground-based siblings, we are uncovering a new category of star clusters: the dust-enshrouded super-star clusters. These manifest themselves only beyond a few microns, as their shroud of dust is able to block all light emitted by the stars themselves. Here we present our results on the spectacular cluster in SBS 0335-052, a very metal-poor galaxy. We also point to the growing number of galaxy analogs to sbs 0335-052, revealing the possibility that these clusters signal a major mode of star formation in starbursts. We conclude by listing a number of open points these clusters raise, in particular with respect to high-redshift counterparts.
November 8, 16:30 hr: Dr. Christian HUMMEL
Abstract The US Naval Observatory in Washington, DC, has been involved with the Mark III Stellar Interferometer on Mount Wilson, California, and is currently building the Navy Prototype Optical Interferometer (NPOI) at Lowell Observatory in Flagstaff, Arizona, in collaboration with the Naval Research Lab. Based on our experience with the Mark III, the NPOI was designed as a six-station reconfigurable array optimized for imaging multiple stellar systems and stellar surfaces with baselines of up to 430 m. After observing double stars, stellar diameters and limb darkening with three stations for several years, the NPOI achieved simultaneous six-station combination earlier this year 2002.
I will describe both the technical and scientific highlights of our research into optical long baseline interferometry which brought us to this point, and discuss our current endeavors to make imaging of complex structures with milliarcsecond resolution a reality. I will thus touch upon areas of mutual interest to the NPOI and VLTI interferometers, and, as a matter of fact, to any modern interferometry project.
November 12, 16:30 hr: Dr. Andrew BUNKER
Abstract I will talk about CIRPASS - the first near-infrared integral field spectrograph on an 8-m telescope. We have recently successfully commissioned CIRPASS on Gemini-South. I will describe our demonstration science programme, which highlights the many advantages of "3D" area spectroscopy over traditional techniques. I will show our first results on studies of the kinematics and star formation in z~1 galaxies, as well as spatially-resolved spectroscopy of Galactic and low-redshift targets obtained during the commissioning this August.
December 6, 11:30 hr: Dr. Stefan WAGNER
Abstract While jets in active galactic nuclei have been identified as the most powerful accelerators in the universe several decades ago, several basic characteristics remain unknown. The advent of large optical telescopes, new X-ray instrumentation and a revolution in gamma-ray astrophysics shed new light on long standing questions concerning the acceleration, matter content and power budget of large-scale jets.
December 16, 16:30 hr: Dr. Daniel KUNTH
Abstract I review the impact of a starburst event into the interstellar medium as deduced from the observational properties of HII galaxies (massive stars, metallicity studies, Lyalpha studies etc...)and the intergalactic medium. Inferences about the halos of gas rich galaxies will be discussed. Finally I'll examine the extent to which Lyalpha can be used to derive the cosmic star formation rate and to constrain the search for high redshift galaxies. Ongoing program on HST-ACS will be presented.