BEGIN:VCALENDAR VERSION:2.0 X-WR-TIMEZONE:Europe/Paris CALSCALE:GREGORIAN PRODID:-//SPIP/Plugin Agenda//NONSGML v1.0//FR X-WR-CALNAME;VALUE=TEXT:LAM - Laboratoire d’Astrophysique de Marseille -- Agenda X-WR-RELCALID: BEGIN:VEVENT SUMMARY:Séminaires : Teresa Antoja UID:evenement346 @ DTSTAMP:20200114T125951Z DTSTART:20200626T090000Z DTEND:20200626T100000Z CREATED:20200114T125951Z LAST-MODIFIED:20200114T125951Z LOCATION:Amphi CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Sandrine Codis UID:evenement345 @ DTSTAMP:20200114T125914Z DTSTART:20200619T090000Z DTEND:20200619T100000Z CREATED:20200114T125914Z LAST-MODIFIED:20200114T125914Z LOCATION:Amphi CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Guy Perrin UID:evenement344 @ DTSTAMP:20200114T125817Z DTSTART:20200612T090000Z DTEND:20200612T100000Z CREATED:20200114T125817Z LAST-MODIFIED:20200114T125817Z LOCATION:Amphi CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Sylvestre Lacour UID:evenement343 @ DTSTAMP:20200114T125743Z DTSTART:20200605T090000Z DTEND:20200605T100000Z CREATED:20200114T125743Z LAST-MODIFIED:20200114T125743Z LOCATION:Amphi CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Oliver Hahn UID:evenement342 @ DTSTAMP:20200114T125246Z DTSTART:20200529T090000Z DTEND:20200529T100000Z CREATED:20200114T125246Z LAST-MODIFIED:20200114T125246Z LOCATION:Amphi CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Georgios Magdis UID:evenement341 @ DTSTAMP:20200114T125201Z DTSTART:20200515T090000Z DTEND:20200515T100000Z CREATED:20200114T125201Z LAST-MODIFIED:20200114T125201Z LOCATION:Amphii CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaires : Michel Gonin UID:evenement340 @ DTSTAMP:20200114T125008Z DTSTART:20200403T090000Z DTEND:20200403T100000Z CREATED:20200114T125008Z LAST-MODIFIED:20200114T125008Z CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaire : Nicolas Prantzos UID:evenement339 @ DTSTAMP:20200114T124909Z DTSTART:20200327T100000Z DTEND:20200327T110000Z CREATED:20200114T124909Z LAST-MODIFIED:20200114T124909Z CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaire : B. Vollmer UID:evenement338 @ DTSTAMP:20200114T124753Z DTSTART:20200320T100000Z DTEND:20200320T110000Z CREATED:20200114T124753Z LAST-MODIFIED:20200114T124753Z CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaire : Elise Vernet (ESO) UID:evenement337 @ DTSTAMP:20200114T124545Z DTSTART:20200214T100000Z DTEND:20200214T110000Z CREATED:20200114T124545Z LAST-MODIFIED:20200114T125037Z LOCATION:Amphi DESCRIPTION:Design and performance of the ESO ELT adaptive and fast steering mirrors CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Gaitee Hussain (ESO) "The evolution of magnetic activity in solar-type stars" UID:evenement347 @ DTSTAMP:20200127T160217Z DTSTART:20200131T100000Z DTEND:20200131T110000Z CREATED:20200127T160217Z LAST-MODIFIED:20200127T160217Z DESCRIPTION:Solar-type stars display signs of magnetic activity at all wavelengths\, from energetic X-ray and UV flares to photometric variability caused by the presence of large cool spots. The magnetic activity in solar-type stars evolves as they age\, affecting the environment in which planets themselves form and evolve. Over the past two decades Doppler imaging techniques have allowed us to detect and map the surface magnetic fields of solar-type stars over a wide range of evolutionary states. In this talk I will explain how we derive and interpret magnetic field maps of solar-type stars and review what they have taught us about the evolution of magnetic activity from the PMS stage through to our own Sun. CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Séminaire : S.Basa & L.Martin UID:evenement336 @ DTSTAMP:20200113T122033Z DTSTART:20200117T100000Z DTEND:20200117T110000Z CREATED:20200113T122033Z LAST-MODIFIED:20200113T122033Z LOCATION:Amphi DESCRIPTION:Séminaire : S.Basa & L.Martin CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Programme des séminaires UID:evenement335 @ DTSTAMP:20191210T111430Z DTSTART:20191220T100000Z DTEND:20191220T110000Z CREATED:20191210T111430Z LAST-MODIFIED:20191210T111430Z LOCATION:Amphi DESCRIPTION:Friday Seminar Florence Durret - (IAP and Sorbonne Universite) "Galaxy clusters and their environment" CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Bruno Sicardy "Stellar occultations of TNOs" UID:evenement334 @ DTSTAMP:20190903T155902Z DTSTART:20190927T090000Z DTEND:20190927T100000Z CREATED:20190903T155902Z LAST-MODIFIED:20190903T155902Z CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Christophe Dumas "The Thirty Meter Telescope" UID:evenement333 @ DTSTAMP:20190903T155720Z DTSTART:20190913T090000Z DTEND:20190913T100000Z CREATED:20190903T155720Z LAST-MODIFIED:20190903T155720Z CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Annie HUGHES "PHANGS : Star formation\, feedback and chemical enrichment in nearby galaxies" UID:evenement332 @ DTSTAMP:20190903T155447Z DTSTART:20190906T090000Z DTEND:20190906T100000Z CREATED:20190903T155447Z LAST-MODIFIED:20190903T155447Z DESCRIPTION:The Physics at High Angular resolution in Nearby Galaxies (PHANGS) project is pursuing thee major observing programmes with ALMA\, VLT/MUSE and the HST in order to study the interplay of the small-scale physics of gas and star formation with galactic structure and galaxy evolution across a representative sample of star-forming main sequence galaxies in the local Universe (d<20Mpc). With observations at high angular resolution (<100pc)\, the PHANGS legacy datasets provide a detailed\, panchromatic view of ionised gas\, stellar light\, and the cold molecular gas in nearby galaxies and enable statistical studies of star formation\, feedback\, and chemical enrichment across different galaxy environments. In this talk\, I will give an overview of the PHANGS project\, and highlight our latest results for the physical conditions in the molecular gas reservoir\, the star formation activity and chemical enrichment in PHANGS galaxies. CATEGORIES:Programme des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Joss Bland-Hawthorn UID:evenement331 @ DTSTAMP:20190702T204749Z DTSTART:20190711T090000Z DTEND:20190711T100000Z CREATED:20190702T204749Z LAST-MODIFIED:20190702T204749Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Joss Bland-Hawthorn UID:evenement330 @ DTSTAMP:20190702T204650Z DTSTART:20190705T090000Z DTEND:20190705T100000Z CREATED:20190702T204650Z LAST-MODIFIED:20190702T204715Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Peter Capack (Caltech) - Developing a Standard Model of Galaxies UID:evenement321 @ DTSTAMP:20190128T092821Z DTSTART:20190628T090000Z DTEND:20190628T100000Z CREATED:20190128T092821Z LAST-MODIFIED:20190621T102310Z DESCRIPTION:In this presentation Peter Capak will argue that a combination of large galaxy surveys and the latest machine learning techniques are allowing astrophysicists to develop a robust statistical model of the extra-galactic universe. If optimally constructed\, this model would encapsulate all available information on the likelihood of observing a given type of galaxy as well as its distribution in space and cosmic epoch. The initial motivation for developing elements of this model was improved constraints on dark energy and dark matter\, but it also contains significant information on how galaxies form and evolve. He will show how early version of this model have significantly improved photometric redshifts for weak lensing and can be used for spectroscopic target selection. He will conclude with examples of how he is using his models to optimally design observation with facilities in high demand such as Keck\, ALMA\, and the future JWST and what future techniques need to be developed. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Hendrik Hildebrandt (Alfa-Bonn) - Cosmological Weak Gravitational Lensing UID:evenement327 @ DTSTAMP:20190326T103700Z DTSTART:20190621T090000Z DTEND:20190621T100000Z CREATED:20190326T103700Z LAST-MODIFIED:20190614T081913Z DESCRIPTION:Gravitational lensing represents a unique tool to study the dark Universe. Small distortions in the images of galaxies caused by the gravitational lensing effect of the matter distribution in the Universe can be detected over the whole sky. Measuring these coherent distortions makes dark matter structures "visible"\, allows us to study their growth over cosmic time\, and yields cosmological insights complementary to other probes like the cosmic microwave background (CMB). Ongoing wide-field imaging surveys exploit this weak gravitational lensing technique to come up with competitive constraints on important cosmological parameters and insights on fundamental physics. In this talk I will first introduce the basic concepts of weak gravitational lensing\, review the history and challenges of weak lensing measurements\, and then concentrate on recent results from the ongoing European Kilo Degree Survey (KiDS) and VISTA Kilo-degree Infrared Galaxy Public Survey (VIKING) projects. These KiDS/VIKING measurements show some tension with CMB measurements from the Planck mission when the standard cosmological model is assumed. The results will be put into context and compared to findings from the two other big cosmic shear experiments (HSC and DES). I will also present brand-new results from a Self-Organised-Map-based calibration of the KiDS+VIKING redshifts and how this influences the cosmological conclusions. Through a careful re-assessment of the HSC and DES results I will show that the discrepancies in large-scale-structure parameters we are seeing today are approaching a level of significance that is similar to the tension in the Hubble constant. Taken together this might hint at a serious problem of the standard ΛCDM paradigm in simultaneously explaining early- and late-time cosmic structure formation. I will conclude with an outlook towards the big experiments of the next decade in this field of research\, Euclid and the Large Synoptic Survey Telescope that have the potential to yield some definitive answers to these questions. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Vianney Lebouteiller (Laboratoire AIM - CEA Saclay) - The interstellar medium of nearby primitive galaxies UID:evenement324 @ DTSTAMP:20190128T093216Z DTSTART:20190614T090000Z DTEND:20190614T100000Z CREATED:20190128T093216Z LAST-MODIFIED:20190612T075904Z DESCRIPTION:The lack of detection of cold molecular gas in blue compact dwarf (BCD) galaxies is at variance with their intense star-formation episode. In particular\, CO\, often used a tracer of H2 through a conversion function\, is selectively photodissociated in dust-poor environments. A potentially large fraction of H2 is thus expected to reside in the so-called CO-free gas\, where it could be traced by neutral gas observed with infrared cooling lines [CI]\, [CII]\, and [OI]. Although the fraction of CO-free gas to total molecular gas is expected to be relatively large in metal-poor galaxies\, a definite evidence is still lacking because of the difficulty in associating cooling lines with any given heating mechanism. The main issue at stake is to understand the role of molecular gas in the star formation process. I will first show that the heating mechanism in the neutral gas cannot be dominated by the photoelectric effect on dust grains below a threshold metallicity due to a low abundance of dust and polycyclic aromatic hydrocarbons. I will then present results from a study on the dwarf galaxy IZw18 ( 2% solar metallicity) recently published in Lebouteiller et al. (2017). Optical and infrared lines are used to constrain the physical conditions in the HII region + HI region within a consistent photoionization and photodissociation model. We show that the HI region is entirely heated by a single ultraluminous X-ray source with important consequences on the applicability of [CII] to trace the star-formation rate and to trace the CO-free gas. We derive stringent upper limits on the size of H2 clumps that may be detected in the future with JWST and IRAM/NOEMA. We also show that the nature of the X-ray source can be constrained through the use of our models. I will conclude by proposing that star formation may be quenched in extremely metal-poor dwarf galaxies due to X-ray photoionization. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Nicolas Prantzos (IAP) - L'énergie des étoiles (une brève histoire d'astrophysique nucléaire) UID:evenement323 @ DTSTAMP:20190128T093145Z DTSTART:20190607T090000Z DTEND:20190607T100000Z CREATED:20190128T093145Z LAST-MODIFIED:20190528T085454Z DESCRIPTION:je présenterai les différentes étapes qui ont mené à notre compréhension de la source de l'énergie stellaire\, depuis les premières idées d'une origine gravitationnelle (19ème siècle)\, en passant par les apports de la mécanique quantique dans les années 1920 et les découvertes de la physique nucléaire dans les années 1930 qui ont finalement permis d'élucider le problème. J'essaierai de placer ces développements et leurs protagonistes dans le contexte (politique et culturel) de leur époque. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Lutz Wisotzki (Leibniz Institut für Astrophysik Potsdam AIP) - The high-redshift universe in Lyman-alpha emission UID:evenement322 @ DTSTAMP:20190128T093008Z DTSTART:20190524T090000Z DTEND:20190524T100000Z CREATED:20190128T093008Z LAST-MODIFIED:20190520T151705Z DESCRIPTION:Lyman-alpha radiation is a natural signature of star-forming galaxies and has been used since long to identify high-redshift objects. I present observations with the MUSE instrument at the ESO-VLT that have revealed more than 1000 Lyman-alpha emitters\, some of them extremely faint. Moreover\, we find ubiquitous extended Ly-alpha emitting envelopes around individual normal (non-AGN) galaxies at redshifts z > 3. These Ly-alpha haloes indicate huge reservoirs of cold gas in the circumgalactic medium. At the sensitivity level reached by MUSE\, a large fraction of the field of view is actually covered with Lya emission from redshifts 3 < z < 6. The corresponding cross-sections are comparable to those of high-column density hydrogen absorbers\, suggesting that most atomic hydrogen at these redshifts has now also been detected in emission. Our observations provide direct insights into the spatial distribution of at least partly neutral gas in the circumgalactic medium of low mass galaxies at z > 3. I also discuss some implications for the demographics of high-redshift galaxies. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Francesco Pepe (Geneva) - ESPRESSO - High-fidelity spectroscopy with the VLT UID:evenement329 @ DTSTAMP:20190515T071702Z DTSTART:20190517T090000Z DTEND:20190517T100000Z CREATED:20190515T071702Z LAST-MODIFIED:20190515T071702Z DESCRIPTION:ESPRESSO has started operations at the VLT on October 2018. It is the first HARPS-like spectro-velocimeter installed on a 10-m class telescope and able to collect incoherently the light of up to 4-UTs simultaneously\, exploiting thus the collecting area of an equivalent 16-m telescope. ESPRESSO is designed for ultra-precise Doppler measurements and high-fidelity astronomical spectroscopy\, and aims at searching and characterizing rocky extra-solar planets in the habitable zone of solar-type stars. The planet Proxima Cen b\, which was recently discovered with HARPS\, is a foretaste of what may be possible with ESPRESSO\, but the high spectroscopic fidelity of ESPRESSO will also allow us to do transit spectroscopy of exoplanets\, study the RM effect on faint objects\, performing stellar spectroscopy in the milky way and in neighbouring galaxies\, study the variability of physical constants\, etc. In my talk I will describe the ESPRESSO instrument\, its science drivers\, and preliminary performances and results from the Commissioning and the first observation period. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Serena Viti (UCL) - Characterizing the dense gas in galaxies UID:evenement326 @ DTSTAMP:20190326T103610Z DTSTART:20190510T090000Z DTEND:20190510T100000Z CREATED:20190326T103610Z LAST-MODIFIED:20190405T080817Z DESCRIPTION:It is now well established that chemistry in external galaxies is rich and complex. In this talk I will give an overview of the field of Astrochemistry\, with special emphasis on its relevance to extragalactic studies. I will show how molecules play a key role in the formation and shaping of galaxies. By using examples from different regions of space\, from starburst regions\, to gas surrounding AGNs\, I will demonstrate how important molecules are for the characterization of galaxies. Finally I will present a new approach for the interpretation of molecules using Bayesian and Machine Learning techniques. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:John Carter (Institut d'Astrophysique Spatiale) - The water story of Early Mars through compositional remote sensing : lessons learned and future prospects for exploration UID:evenement328 @ DTSTAMP:20190429T132056Z DTSTART:20190503T090000Z DTEND:20190503T100000Z CREATED:20190429T132056Z LAST-MODIFIED:20190429T132056Z DESCRIPTION:Water on early Mars has left chemical fingerprints which survive today as secondary "aqueous" minerals : clays\, salts and other species. Their study allows piecing together the geochemical conditions on early Mars\, to trace the potential past habitability of the planet and its ability to have sequestered organic matter over geologic time scales. The pervasive processes of water - rock interactions preserved at Mars are also a window into Hadean Earth\, a period when conditions are thought to have been conducive to life but of which the record has been obliterated. Aqueous minerals are also prospective resources for future human missions to Mars. Since their discovery 15 years ago\, a large diversity of mineral phases and geologic contexts have been found\, but Mars has been slow to reveal its secrets. It is still not understood what the dominant mode of alteration was\, if it was connected to a hydrological cycle as on Earth\, and its potential for organic matter evolution and preservation. Future missions and instrument concepts are being prepared which will allow refined in-situ studies of the aqueous mineralogy and search for associated organics. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Roser Juanola-Parramon (NASA Goddard / UMBC) - Detecting exoplanets with the next generation of space telescopes : a technical perspective UID:evenement325 @ DTSTAMP:20190326T103451Z DTSTART:20190405T090000Z DTEND:20190405T100000Z CREATED:20190326T103451Z LAST-MODIFIED:20190326T133226Z DESCRIPTION:Direct imaging of exoplanets in their habitable zone is extremely challenging due to two main factors : the proximity of the planet to the parent star and the flux ratio between the planet and the parent star\, usually to the order of 10^-10 in the visible. In January 2016\, NASA commissioned four Mission Concept Studies for the next Decadal Survey\, which will decide which kind of mission will follow the steps of extremely successful telescopes like Hubble\, and the future JWST and WFIRST. Of these four studies\, two of them have as a primary scientific goal to detect and characterize exoplanets in their habitable zone. These two missions are the Large UV-Optical-Infrared (LUVOIR) Surveyor and the Habitable exoplanet Imaging Mission (HabEx)\, which require large apertures and coronagraphs with active wavefront control to be able to suppress the starlight so faint planets can be detected and characterized adjacent to their parent star. The Extreme Coronagraph for Living Planet Systems (ECLIPS) is the coronagraph instrument on the LUVOIR Surveyor mission concept. It is split into three channels : UV (200 to 400 nm)\, optical (400 nm to 850 nm)\, and NIR (850 nm to 2.0 microns)\, with each channel equipped with two deformable mirrors for wavefront control\, a suite of coronagraph masks\, a low-order/out-of-band wavefront sensor\, and separate science imagers and spectrographs. The Apodized Pupil Lyot Coronagraph (APLC) is one of the baselined mask technologies to enable 10^-10 contrast observations in the habitable zones of nearby stars. The LUVOIR concept uses a large\, segmented primary mirror (8- 15 meters in diameter) to meet its scientific objectives. For such an observatory architecture\, the coronagraph performance depends on active wavefront sensing and control and metrology subsystems to compensate for errors in segment alignment (piston and tip/tilt)\, secondary mirror alignment\, and global low-order wavefront errors. For the LUVOIR-A architecture (15m obscured telescope)\, we evaluate the sensitivity to segment-to-segment tip/tilt\, piston\, power (focus)\, astigmatism\, coma\, trefoil and spherical errors\, and to errors induced by misalignment of the secondary mirror. I will present the latest results of the simulation of these effects and discuss the achieved contrast for exoplanet detection and characterisation under these circumstances. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:David Ehrenreich (U. Geneva) - Exoplanetary atmospheres at high spectral resolution UID:evenement320 @ DTSTAMP:20190128T092729Z DTSTART:20190329T100000Z DTEND:20190329T110000Z CREATED:20190128T092729Z LAST-MODIFIED:20190326T103517Z DESCRIPTION:Observing transits of exoplanets with the Hubble Space Telescope in the ultraviolet has revealed spectacular atmospheric escape of strongly irradiated gas giants. This atmospheric photo-evaporation could explain the dearth of intermediate-mass planets close to their stars\, as well as the valley separating two populations of super-Earths. The deposition of a tremendous amount of high-energy irradiation in the outer atmospheric layers of exoplanets should also impact their physical and chemical properties. I will review recent observations obtained wh ground-based\, high-resolution spectrographs\, that unveil the extreme conditions reigning in the upper atmospheres of exoplanets. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Coralie Neiner (LESIA\, Observatoire de Meudon\, France) - Space UV spectropolarimetry UID:evenement317 @ DTSTAMP:20190117T113811Z DTSTART:20190322T100000Z DTEND:20190322T110000Z CREATED:20190117T113811Z LAST-MODIFIED:20190312T090756Z DESCRIPTION:In many domains of astrophysics\, the study of magnetism and polarized light has become a new and essential tool. This has however never been done in the UV as it requires to go into space. I will present recent R&D work on UV polarimeters and current studies of space mission projects equipped with a high-resolution UV spectropolarimeter\, such as Pollux for LUVOIR\, Arago\, or Lodestar. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Sebastian Kamann (Liverpool John Moores University) - Dynamical clues to the formation of star clusters UID:evenement316 @ DTSTAMP:20190117T113708Z DTSTART:20190315T100000Z DTEND:20190315T110000Z CREATED:20190117T113708Z LAST-MODIFIED:20190305T081347Z DESCRIPTION:The star cluster population of the Milky Way provides a unique window to study the formation history of our Galaxy. The conditions of the epochs when the Milky Way built up most of its stellar mass are preserved in the star clusters we observe to date. However\, the physics governing the formation of star clusters are still not entirely understood. For example\, ancient globular clusters show subtle differences in the chemical compositions of their stars which appear to be absent in the clusters forming today. Does this suggest that cluster formation varies with mass or cosmic age ? In my presentation\, I want to show how we can use the stellar dynamics of the clusters to answer such questions. Thanks to satellites such as Hubble or Gaia and powerful spectrographs we can nowadays study the motions of representative samples of stars in clusters of all ages. Using data from the MUSE spectrograph\, we could already show that rotation played a crucial role in the formation of globular clusters and that they harbour larger populations of black holes than previously thought. We are further using the data to search for differences in the kinematics of their stellar populations. If detected\, such differences put stringent constraints on the mechanisms that led to the formation of multiple populations in globular clusters. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Martin Crocce (IEEC-CSIC) - Accelerated Cosmic Expansion and the Dark Energy Survey UID:evenement319 @ DTSTAMP:20190128T092544Z DTSTART:20190308T100000Z DTEND:20190308T110000Z CREATED:20190128T092544Z LAST-MODIFIED:20190305T081302Z DESCRIPTION:The striking discovery that the Cosmic expansion is not slowing down but accelerating has turned into one of the puzzles in Cosmology sparking large observational campaigns to map the Large Scale Structure and geometry of the Universe across cosmic time. I will briefly review this effort and then discuss The Dark Energy Survey (DES)\, a state-of-the-art large-scale galaxy survey designed to understand such acceleration by mapping 5000 deg2 measuring the positions and shapes for 300 million galaxies up to redshift 1\, the light-curves of several thousand supernovae\, and the masses of tens of thousands of galaxy clusters. I will present the latest cosmological results from the first year of observations\, in particular those related to the combination of large-scale structure and weak gravitational lensing\, how they compare with those from other datasets\, and what to expect in the near future. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:NISP team (LAM) - NISP/EUCLID technical presentation and status. UID:evenement318 @ DTSTAMP:20190128T092455Z DTSTART:20190301T100000Z DTEND:20190301T110000Z CREATED:20190128T092455Z LAST-MODIFIED:20190221T115524Z DESCRIPTION:The NISP (Near Infrared Spectrometer and Photometer) is one of the two instruments to fly on the ESA Euclid spacecraft mid 2022. It operates in the near-IR spectral region (900-2000nm) as a photometer and spectrometer. The instrument is composed of : a cold (135K) optomechanical subsystem consisting of a Silicon carbide structure\, an optical assembly\, a filter wheel mechanism\, a grism wheel mechanism\, a calibration unit and a thermal control system a detection system based on a mosaic of 16 H2RG with their front-end readout electronic. a warm electronic system (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data We will present : the Euclid spacecraft the NISP final architecture\, the different subsystems and the main performances the NISP development plan\, the test plan and the schedule the NISP EM and FM integration CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Erika Hamden (U. Arizona) - TDB UID:evenement315 @ DTSTAMP:20190117T113554Z DTSTART:20190208T100000Z DTEND:20190208T110000Z CREATED:20190117T113554Z LAST-MODIFIED:20190117T113554Z DESCRIPTION:TBD CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Sera Markoff (API/GRAPPA\, University of Amsterdam) - Imaging (and imagining) Black Holes UID:evenement314 @ DTSTAMP:20190117T113344Z DTSTART:20190201T100000Z DTEND:20190201T110000Z CREATED:20190117T113344Z LAST-MODIFIED:20190117T171942Z DESCRIPTION:Black holes are one of the most exotic consequences of Einstein’s General Relativity\, yet they are also very common players in the Universe\, existing on scales ranging from the stellar up to beasts over a billion times more massive than our sun. Contrary to their reputation as cosmic vacuum cleaners\, they actually serve as engines for extremely energetic processes\, playing a major role in regulating the growth of galaxies. Some black holes also launch enormous jets of relativistic plasma that accelerate particles to energies millions of times higher than the Large Hadron Collider at CERN. Astronomers\, astrophysicists and physicists all have reasons for wanting to understand black holes\, yet we have been limited by the resolution of our telescopes from actually seeing one directly. This situation has changed dramatically with the coming of the Event Horizon Telescope\, an Earth-sized array operating in the millimeter wavelength regime\, that can actually make pictures of a couple of nearby supermassive black holes such as the one in our Galactic centre\, Sgr A*\, and the active galactic nucleus M87. I will briefly introduce the phenomenology of black hole accretion\, and discuss some of the key problems we are still facing in terms of building a working model for these processes\, and show some examples of the current cutting edge in modelling and interpretation. Along the way I will explain what the Event Horizon Telescope is\, and how we anticipate the groundbreaking data from the first full run in April 2017 (note : I will not be able to show the results yet !) will help revolutionise our field and shed light on these complex environments. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Licia Verde (ICCUB) - The importance of bias UID:evenement313 @ DTSTAMP:20180904T143731Z DTSTART:20190125T100000Z DTEND:20190125T110000Z CREATED:20180904T143731Z LAST-MODIFIED:20190117T154751Z DESCRIPTION:In cosmology bias is used in two different contexts. In one case it refers to systematic errors in a measurement or a determination of model’s parameters. In the other case it refers to the relation between the clustering of mass and that of observable tracers such as galaxies. I will touch upon both aspects. I will highlight the importance of considering and modelling the effect of systematic errors and I will present a model of the halo bias in massive neutrinos cosmologies. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Mark Sargent (Sussex) - Environment and interactions - How (not) to produce a starburst galaxy UID:evenement312 @ DTSTAMP:20180904T143656Z DTSTART:20190118T100000Z DTEND:20190118T110000Z CREATED:20180904T143656Z LAST-MODIFIED:20190109T095209Z DESCRIPTION:Over the last 10 billion years the typical activity level of star-forming galaxies has decreased by more than an order of magnitude. Observations reveal that\, at both low and and high redshift\, there is a population of ‘starburst’ galaxies that are significantly more active than the bulk of the rest of the population. Despite being comparatively rare\, these starbursts are among the most popular targets for detailed studies of astrophysical processes\, by virtue of being bright and thus readily observable. But what does it take to produce a starburst event during the peak epoch of galaxy formation at z 2\, when even the average star-formation rate of the star-forming galaxy population was as high as locally observed only for the most extreme starbursting systems ? In my talk I will present new measurements of the composition of the starburst population at z<2\, in terms of its split into ‘normal’ and interacting or merging galaxies. I will also review how a high star-formation efficiency - one of the trademarks of starburst events - is linked to galaxy environment based on the increasing body of literature on the interstellar medium in high-z galaxy clusters. Finally\, I will discuss how measurements of host galaxy star-formation efficiency can provide clues on the interplay between starburst and AGN activity. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Pierre Beck (IPAG) - Shedding light on the darkest Solar System objects UID:evenement311 @ DTSTAMP:20180904T143613Z DTSTART:20181207T100000Z DTEND:20181207T110000Z CREATED:20180904T143613Z LAST-MODIFIED:20181128T154552Z DESCRIPTION:Comets and most asteroids are extremely dark objets. They typically reflect only a few percent of the incoming light. I will discuss the nature of dark Solar System small bodies based on ground-based observations\, in situ observation (i.e. VIRTIS / ROSETTA) and laboratory measurements. I will discuss in particular the case of C-type near-Earth asteroids\, which are being targetted by two sample-return missions and how they might (or not) be representative of the main-belt population. Finally\, I will discuss the case of cometary nuclei\, possessing a peculiar absorption around 3-µm as observed by VIRTIS/ROSETTA. I will discuss how cometary nuclei relate to asteroid spectral-type and the nature of this spectral feature. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Chiara Caprini (APC Paris) - Cosmology with LISA UID:evenement310 @ DTSTAMP:20180904T143540Z DTSTART:20181130T100000Z DTEND:20181130T110000Z CREATED:20180904T143540Z LAST-MODIFIED:20181112T101829Z DESCRIPTION:Gravitational waves can constitute a unique probe of both the early and late-time universe. After a general introduction to the subject\, this seminar focuses on the potential of the space-based interferometer LISA to test cosmology. In particular\, two aspects will be discussed : the stochastic gravitational wave background generated by sources in the very early universe\, and the use of compact binaries\, emitting gravitational waves\, as standard sirens\, i.e. to probe the energy content and the acceleration of the late-time universe. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Ferrara (SNS\, Pise) - The Interstellar Medium of High Redshift Galaxies UID:evenement309 @ DTSTAMP:20180904T143457Z DTSTART:20181123T100000Z DTEND:20181123T110000Z CREATED:20180904T143457Z LAST-MODIFIED:20181011T161502Z DESCRIPTION:In the last decade we have explored the cosmic depths and found a statistically significant number of galaxies well into the Epoch of Reionization. However\, our physical knowledge of these pristine objects remains very scant. Investigating the internal structure\, interstellar medium and evolution of early galaxies is the next challenge to understand key processes as the cosmic history of baryons\, feedback\, reionization and metal enrichment of the intergalactic medium\, This ambitious plan can be tackled by combining a new generation of physically-rich\, high resolution\, zoom simulations with data in the sub-mm bands provided by ALMA. This approach will be soon strengthened by the forthcoming JWST power. I will review the present status and the open questions in the field. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Joel Vernet (ESO) - A multi-phase study of the Circum Galactic Medium in High-z radio galaxies with MUSE and ALMA UID:evenement308 @ DTSTAMP:20180904T143415Z DTSTART:20181116T100000Z DTEND:20181116T110000Z CREATED:20180904T143415Z LAST-MODIFIED:20181112T101440Z DESCRIPTION:Radio galaxies (radio loud type-2 AGN) are among the most massive and luminous galaxies known at any redshift. They are found in high density environments (proto-clusters) and since the 1990s\, it is known that they are surrounded by massive haloes extending to 150-200 kpc. These emission-line haloes extend well beyond the boundaries of the host galaxy\, and form the link between its inter-stellar medium and the intra-cluster gas in the proto-cluster environment\, i.e. the Circum Galactic Medium (CGM). They may well represent the accretion flows feeding the host galaxies with primordial gas from filamentary large-scale structures. The AGN is the flashlight illuminating and revealing these structures which play a crucial role in the galaxy formation process. In this talk\, I will present the results of an on-going VLT/MUSE and ALMA study of a sample of radio galaxies at 3 2) are starting to confirm the importance of massive stars in shaping galaxy emission and evolution. The intense starbursts common at high redshift\, are rare but identifiable in local analogue galaxies. Understanding these populations\, and their evolution with age and heavy element content is likely to be key to interpreting processes such as supernova and gamma-ray burst rates\, cosmic reionization and the chemical enrichment of the Universe through galaxy-scale winds. It can even be important for the history of habitability on galaxy scales. One avenue of exploring these populations is through the study of local galaxies which share the star formation properties of the distant Universe. A second\, overlapping\, approach is through modelling. Distant stellar populations are unresolved\, and the limited data available must be interpreted in the context of stellar population models. With the upcoming launch of JWST and the promise of observations of galaxies within a billion years of the Big Bang\, the uncertainties in modelling massive stars are becoming increasingly important to our interpretation of the high redshift Universe. In turn\, these observations of distant stellar populations will provide ever stronger tests against which to gauge the success of\, and flaws in\, current massive star models. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Michael Gillon (Liège) - The SPECULOOS transit survey : hunting for red worlds UID:evenement298 @ DTSTAMP:20180122T153001Z DTSTART:20180608T090000Z DTEND:20180608T100000Z CREATED:20180122T153001Z LAST-MODIFIED:20180604T091234Z DESCRIPTION:The thorough characterization of temperate terrestrial exoplanets holds the promise of revolutionizing our understanding of rocky worlds by enabling us to assess their diversity at the galactic scale\, not only in terms of orbits\, but also in terms of atmospheric compositions\, surface conditions\, and habitability. In this context\, the 1000 brightest ultracool (M7-type and latter) dwarf stars are particularly interesting targets for a transit search\, as their proximity combined to their small size and faint luminosity should make possible the characterization of a transiting temperate planet as small as the Earth -and even smaller- with upcoming facilities. In this talk\, I will present SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars)\, a new photometric survey that aims to explore for transits these faint nearby stars. It is based on a network of 1m-class robotic telescopes whose main nodes will be the SPECULOOS-South and SPECULOOS-North Observatories\, each composed of four 1m telescopes optimized for high-precision photometry in the very-near-infrared (0.7 to 1 microns). While the installation of SPECULOOS-North has just been initiated at Teide Observatory (Tenerife)\, SPECULOOS-South is under commissioning at Paranal Observatory (Chile) and should be fully operational for the end of the year. The high scientific potential of the project was recently established by its discovery of the amazing TRAPPIST-1 (aka SPECULOOS-1) system\, of which I will review the ongoing characterization and its exciting perspectives. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:George Ellis - On the philosophy of cosmology UID:evenement297 @ DTSTAMP:20180122T152840Z DTSTART:20180601T090000Z DTEND:20180601T100000Z CREATED:20180122T152840Z LAST-MODIFIED:20180528T094200Z DESCRIPTION:This talk will summarise what we presently know and don’t know about the physical universe\, and consider limits to what we probably ever will know due to the unique nature of the universe and existence of observational horizons. It will discuss problems with our current model such as the unknown nature of dark energy and the mechanism of inflation\, and the consequent importance of investigating alternative models of the universe and effects such as the backreaction of structure on its evolution. Finally it will consider whether multiverse proposals should be considered as scientific or philosophical proposals. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Jayne Birkby (University of Amsterdam) - New Frontiers in Exoplanet Characterization UID:evenement296 @ DTSTAMP:20180122T152412Z DTSTART:20180525T090000Z DTEND:20180525T100000Z CREATED:20180122T152412Z LAST-MODIFIED:20180522T082828Z DESCRIPTION:Exoplanet characterization is undergoing a rapid evolution\, especially in the study of exoplanet atmospheres. I will discuss the very latest results from both space and ground-based observations and highlight how they are helping us to understand exoplanet origins and diversity. I will focus part of my talk on high-resolution spectroscopy\, which is a robust and powerful tool in exoplanet characterization. It uses changes in the Doppler shift of a planet to disentangle its spectrum from the glare of its host star. The technique is sensitive to the depth\, shape\, and position of a planet’s spectral lines\, and thus reveals information about the planet’s composition\, atmospheric structure\, mass\, global wind patterns\, and rotation. I will present some exciting preliminary results from MEASURE : the MMT Exoplanet Atmosphere SURvEy. This 40 night survey is the largest high-resolution study of exoplanet atmospheres to date\, containing day and night side spectra of transiting and non-transiting hot Jupiters and Saturns. Its goal is to provide a homogenous dataset to perform comparative exoplanetology\, and provide complementary high-resolution spectra for exoplanets observed with HST and Spitzer. The combination of high and low-resolution spectroscopy can provide stringent constraints on planet metallicity and C/O ratios\, and signifies the next step in the detailed characterization of exoplanet atmospheres. I will also discuss how the study of exoplanet atmospheres in reflected light\, and over time\, can help reveal their formation pathways and evolutionary history. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Ravit Helled (Zurich) - The fuzziness of Jupiter's core UID:evenement295 @ DTSTAMP:20180122T152309Z DTSTART:20180518T090000Z DTEND:20180518T100000Z CREATED:20180122T152309Z LAST-MODIFIED:20180514T094540Z DESCRIPTION:Giant planets are thought to have cores in their deep interiors\, and the division into a heavy-element core and hydrogen-helium envelope is applied in both formation and structure models. I will briefly discuss the standard model for giant planet formation\, and will show that the primordial internal structure of giant planets depends on their growth history\, in particular\, the ratio of heavy element accretion to gas accretion. I will present the expected primordial internal structure of Jupiter and show that its core might not be well-defined. I will also show that Jupiter's deep interior is likely to have an inhomogeneous structure as suggested by new Juno data. Finally\, I will discuss the importance of these results for analyzing the gravity data of the NASA Juno mission\, and their effect on the characterization of giant exoplanets. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar - LAM closed UID:evenement294 @ DTSTAMP:20180122T152208Z DTSTART:20180511T090000Z DTEND:20180511T100000Z CREATED:20180122T152208Z LAST-MODIFIED:20180122T152208Z DESCRIPTION:No seminar CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar - spring holidays UID:evenement293 @ DTSTAMP:20180122T152128Z DTSTART:20180504T090000Z DTEND:20180504T100000Z CREATED:20180122T152128Z LAST-MODIFIED:20180122T152128Z DESCRIPTION:No seminar CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar - spring holidays UID:evenement292 @ DTSTAMP:20180122T151925Z DTSTART:20180427T090000Z DTEND:20180427T100000Z CREATED:20180122T151925Z LAST-MODIFIED:20180122T151925Z DESCRIPTION:No seminar CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Anne Verhamme (Obs. Genève) - Indirect probes of the escape of ionizing radiation from galaxies to unveil the nature of the sources of Cosmic Reionization UID:evenement290 @ DTSTAMP:20180122T151821Z DTSTART:20180420T090000Z DTEND:20180420T100000Z CREATED:20180122T151821Z LAST-MODIFIED:20180417T103827Z DESCRIPTION:Cosmic reionization corresponds to the period in the history of the Universe during which the predominantly neutral intergalactic medium was ionised by the emergence of the first luminous sources. Young stars in primeval galaxies may be the sources of reionization\, if the ionising radiation\, called Lyman continuum (LyC)\, that they produce can escape their interstellar medium : the escape fraction of LyC photons from galaxies is one of the main unknowns of reionization studies. The increasing opacity of the intergalactic medium with redshift renders direct LyC detections impossible during reionisation. Indirect methods are the only probes of LyC leakage in the distant Universe. I will discuss three indirect diagnostics of LyC leakage that were recently reported in the literature. The first diagnostic for LyC leakage relates the escape of the strongly resonant Lyman-alpha radiation from galaxies to the LyC escape (Verhamme et al. 2015)\, and was recently validated by observations (Verhamme et al. 2017). The second diagnostic proposes that the strength of Oxygen lines ratios can trace density-bounded interstellar regions. It was the selection criterion for the successful detection of 6 strong Lyman Continuum Emitters from our team (Izotov 2016a\,b\, 2018). The third diagnostic relates the metallic absorption line strengths to the porosity of the absorbing interstellar gas in front of the stars. These diagnostics will soon become observables at the redshifts of interest with JWST. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Gabriel Pratt (CEA Saclay) - The Advanced Telescope for High-Energy Astrophysics UID:evenement289 @ DTSTAMP:20180122T151628Z DTSTART:20180413T090000Z DTEND:20180413T100000Z CREATED:20180122T151628Z LAST-MODIFIED:20180409T160915Z DESCRIPTION:The Advanced Telescope for High-Energy Astrophysics (ATHENA) is ESA’s second Large mission\, expected to launch in 2030. An observatory mission combining a telescope with large collecting area and state of the art imaging and high resolution spectroscopic capabilities\, Athena is expected to give rise to a transformational leap in our understanding of hot cosmic plasmas. I will describe the current mission design and give an overview of some of the scientific goals\, with an emphasis on large scale structure science. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Eiichiro Komatsu (MPA) - Finding Cosmic Inflation UID:evenement288 @ DTSTAMP:20180122T151535Z DTSTART:20180406T090000Z DTEND:20180406T100000Z CREATED:20180122T151535Z LAST-MODIFIED:20180404T072108Z DESCRIPTION:The cosmic microwave background (CMB) research told us a remarkable story : the structure we see in our Universe such as galaxies\, stars\, planets\, and eventually ourselves originated from tiny quantum fluctuations generated in the early Universe. With the WMAP we have confirmed many of the key predictions of inflation including flatness and statistical homogeneity of our Universe\, Gaussianity and adiabaticity of primordial density fluctuations\, and a small but non-zero deviation from the scale-invariant spectrum of density fluctuations. Yet\, the extraordinary claim requires extraordinary evidence. The last prediction of inflation that is yet to be confirmed is the existence of primordial gravitational waves whose wavelength can be as big as billions of light years. To this end we have proposed to JAXA a new satellite mission called "LiteBIRD"\, whose primary scientific goal is to find signatures of gravitational waves in the polarisation of the CMB. In this presentation we describe the current state of affairs regarding our understanding of the early Universe\, physics of polarisation of CMB\, and the LiteBIRD proposal. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Pratika Dayal (Groningen) - The first billion years of galaxy formation UID:evenement287 @ DTSTAMP:20180122T151325Z DTSTART:20180330T090000Z DTEND:20180330T100000Z CREATED:20180122T151325Z LAST-MODIFIED:20180326T083250Z DESCRIPTION:Galaxy formation in the first billion years mark a time of great upheaval in the history of the Universe : as the first sources of light\, these galaxies ended the 'cosmic dark ages' and produced the first photons that could break apart the hydrogen atoms suffusing all of space starting the process of cosmic reionization. As the earliest building blocks\, the shapeless ellipticals galaxies that formed in the first billion years also determine the physical properties of all subsequent galaxy populations. At the forefront of astronomical research\, the past few years have seen cutting-edge instruments provide tantalising glimpses of such galaxies chaotically assembling in an infant Universe. I will show how this data has provided an unprecedented opportunity to pin down the reionization state of the Universe (at least in its last stages)\, understand their physical properties\, and study the key physics driving their formation and evolution. Finally\, I will try to give a flavour of how the assembly of early galaxies\, accessible with the forthcoming James Webb Space Telescope and the associated reionization history\, can provide a powerful testbed for Warm Dark Matter models. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Olivier Witasse (ESTEC) - JUICE : A European Mission to Jupiter and its Icy Moons UID:evenement286 @ DTSTAMP:20180122T151222Z DTSTART:20180323T100000Z DTEND:20180323T110000Z CREATED:20180122T151222Z LAST-MODIFIED:20180313T102550Z DESCRIPTION:JUICE - JUpiter ICy moons Explorer - is the first large mission in the ESA Cosmic Vision programme. JUICE is due to launch in May 2022. It will arrive at Jupiter in October 2029\, and will spend three years characterizing the Jovian system\, the planet itself\, its giant magnetosphere\, and the giant icy moons Ganymede\, Callisto and Europa. The spacecraft will then orbit Ganymede for a few months. One of the main goals of JUICE is to explore the habitable zone around Jupiter. Ganymede is a high-priority target because it provides a unique laboratory for analyzing the nature\, evolution and habitability of icy worlds\, including the characteristics of subsurface oceans. The payload consists of 10 instruments plus a ground-based experiment using the VLBI network. The speaker is the JUICE project scientist and he will explain the mission\, the science\, the challenges (technical\, human)\, with the help of short videos and animations. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Frans Snik (Leiden) - HIGH-CONTRAST IMAGING WITH LIQUID CRYSTALS UID:evenement285 @ DTSTAMP:20180122T151102Z DTSTART:20180316T100000Z DTEND:20180316T110000Z CREATED:20180122T151102Z LAST-MODIFIED:20180221T084405Z DESCRIPTION:To directly image and characterize exoplanets\, we need advanced optical systems on current Very Large and future Extremely Large telescopes that can suppress the bright glare of stars by 6-10 orders of magnitude\, and analyze the feeble light of potential planetary companions. Such high-contrast imaging systems consist of advanced adaptive optics and associated wavefront sensing techniques\, coronagraphy to (locally) suppress the diffracted starlight\, contrast-enhancing techniques like angular/spectral/polarimetric differential imaging\, and diagnostic capabilities like (high-resolution) spectroscopy and (spectro)polarimetry. In our group in Leiden we cover all these different aspects of high-contrast imaging\, with the aim to achieve the ultimate contrast performance and characterization potential with a complete\, integrated end-to-end system for ground-based telescopes. We are currently exploiting brand-new liquid-crystal technologies that offer important performance benefits for many components in a high-contrast imaging instrument\, and for the system as a whole. We have introduced the “vector-APP” coronagraph that has currently been successfully commissioned at MagAO\, LBT\, and SCExAO\, and are developing versions for several other telescopes and instruments\, including a stratospheric balloon telescope. We apply lessons learnt from the vector-APP to the Vector Vortex Coronagraph to enhance its spectral range and suppression. Novel versions of the vector-APP now have several methods for focal-plane wavefront sensing built in\, and we are currently also testing versions of Pyramid and Zernike wavefront sensors with enhanced performance thanks to liquid-crystal implementations. As vector-APP coronagraphs are broadband\, we are applying them for integral-field spectroscopy\, and developing versions that are optimally matched to fiber-fed spectrographs. And as the vector-APP is based on polarization tricks\, we are extending it with polarimetric implementations. We are currently even playing with crazy liquid-crystal-based Sparse Aperture Masking concepts that are heavily multiplexed\, and can include achromatic nulling. I will provide an overview of these projects\, and an outlook for implementing such techniques at the VLT and the ELT to ultimately characterize rocky planets in the habitable zones of nearby stars. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar - winter holidays UID:evenement284 @ DTSTAMP:20180122T151002Z DTSTART:20180309T100000Z DTEND:20180309T110000Z CREATED:20180122T151002Z LAST-MODIFIED:20180122T152014Z DESCRIPTION:No seminar CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar - winter holidays UID:evenement283 @ DTSTAMP:20180122T150917Z DTSTART:20180302T100000Z DTEND:20180302T110000Z CREATED:20180122T150917Z LAST-MODIFIED:20180122T151948Z DESCRIPTION:No seminar CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Fabrice Madec (LAM) - Zoom sur les intégrations et les tests du spectrographe de l'instrument PFS UID:evenement282 @ DTSTAMP:20180122T150720Z DTSTART:20180223T100000Z DTEND:20180223T110000Z CREATED:20180122T150720Z LAST-MODIFIED:20180214T141859Z DESCRIPTION:L'instrument Prime Focus Spectrograph (PFS) du projet Subaru Measurement of Images and Redshifts (SuMIRe) est développé par un large consortium international pour le télescope japonais SUBARU à Hawaii. Ce spectrographe multi-objet de 2400 fibres est dédié à la cosmologie\, l'étude de l'énergie et de la matière noire ainsi qu'à l'évolution des galaxies et l'archéologie galactique. Nous commencerons par une présentation générale de l'instrument\, les spécificités du projet\, les interfaces. Ensuite\, nous entrerons plus dans le détail des activités d'intégration et de test du spectrographe qui sont faites au LAM. Enfin\, nous finirons par une présentation des futures étapes de l'instrument. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Philippe Andre (CEA Irfu) - From Filamentary Networks to Protostellar Cores in Giant Molecular Clouds : Toward a Unified Picture for Star Formation in Galaxies UID:evenement281 @ DTSTAMP:20180122T150612Z DTSTART:20180216T100000Z DTEND:20180216T110000Z CREATED:20180122T150612Z LAST-MODIFIED:20180214T142132Z DESCRIPTION:I will review recent progress in our observational understanding of the link between the structure of molecular clouds and the formation of low-to intermediate-mass stars. In particular\, I will describe the low-mass star formation scenario favored by Herschel studies of the nearest molecular clouds of the Galaxy which point to the key role of the quasi-universal filamentary structure pervading the cold ISM. The Herschel results support a picture in which molecular filaments and prestellar cores represent two fundamental steps in the star formation process : First\, large-scale compression of interstellar material in supersonic MHD flows generates a cobweb of 0.1 pc-wide filaments in the ISM ; second\, the densest filaments fragment into prestellar cores (and subsequently protostars) by gravitational instability\, while simultaneously growing in mass and complexity through accretion of background cloud material. This filamentary paradigm provides new insight into the origin of the stellar initial mass function and the efficiency of star formation in the dense molecular gas of galaxies. I will end with several open issues and future directions. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Frederique Motte (Université Grenoble Alpes) - High-mass star and cluster formation in the Milky Way : the Herschel/HOBYS\, IRAM/W43-HERO and ALMA-IMF view UID:evenement280 @ DTSTAMP:20180122T145359Z DTSTART:20180209T100000Z DTEND:20180209T110000Z CREATED:20180122T145359Z LAST-MODIFIED:20180207T133222Z DESCRIPTION:The physical process by which stars inherit their properties\, especially their mass\, from those of their parental cloud is the fundamental issue that guides all star formation studies. Our knowledge of this legacy has profound implications for many areas of astrophysics\, including the cosmic history of star formation in galaxies. The star-formation recipes commonly used\, among which the origin of the initial mass function (IMF) and star formation rates (SFR)\, are considered to be universal and thus independent of galactic environments. Our recent studies challenge these recipes\, which are related to our understanding of star formation. I will present the Herschel discovery of high-density cloud filaments\, which are forming clusters of OB-type stars. Given their high star formation activity\, these so-called mini-starburst clouds/ridges could be seen as “miniature and instant models” of starburst galaxies. The characteristics of mini-starburst ridges investigated with the NOEMA and ALMA interferometer challenge star formation models and shed light on the origin of massive clusters. In one of these ridges\, the measured star formation rates (SFR) contradicts statistical models of star formation rates. Moreover\, its measured core mass distribution suggests that the stellar initial mass function (IMF) may not be determined\, in these extreme environments\, at the prestellar stage. These results motivated the setting up the ALMA-IMF Large Program\, project\, which was accepted for Cycle 5 and whose source sample and main objectives will be presented. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Michèle Péron (ESO) — Diversité et inclusion en ingénierie et astronomie (grand public) UID:evenement279 @ DTSTAMP:20180117T155211Z DTSTART:20180202T100000Z DTEND:20180202T110000Z CREATED:20180117T155211Z LAST-MODIFIED:20180122T144938Z LOCATION:Amphi DESCRIPTION:Une main-d'¦uvre diversifiée est essentielle à la satisfaction au travail\, à l¹innovation et à la capacité d'une organisation d'attirer et de retenir les talents. Pour assurer un environment diversifié et créatif\, il est important d¹éliminer non seulement les barrières systémiques (manque de femmes qui s¹engagent dans des études scientifiques) mais également les barrières comportementales comme par example les préjugés inconscients. Cette présentation donnera un aperçu des résultats de la recherche sur l¹impact de ses préjugés inconscients dans le monde du travail. Elle mettra également en lumière diverses initiatives qui existent pour améliorer la diversité et l'inclusion en ingénierie. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Louis le Sergeant d'Hendecourt (PIIM) — From Astrochemistry to Astrobiology : the role of extraterrestrial ices in the build-up of a prebiotic chemistry on telluric planets UID:evenement268 @ DTSTAMP:20170822T162122Z DTSTART:20180126T100000Z DTEND:20180126T110000Z CREATED:20170822T162122Z LAST-MODIFIED:20180111T171147Z LOCATION:Amphi DESCRIPTION:Extraterrestrial ices are observed in many astrophysical environments linked to the formation of stars and planetary systems but also disks and various debris such as comets and asteroids. The chemical evolution of these ices following photo- and thermo-chemistry is routinely simulated in the laboratory. These simulations always end up with the building up of organic materials (semi refractory residues) that show the presence of many molecular bricks of life such as amino acids\, nucleobases and sugars\, including ribose\, a key constituent of RNA. These organics do show also similarities with carbonaceous chondrites and thus suggest an astrophysical scenario in which the delivery of these materials on the primitive Earth may be important\, if not essential to prebiotic chemistry. A general view of these processes will be discussed. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Don Pollacco (Warwick) — Transit surveys of the past\, present and future : the search for Earth 2 UID:evenement267 @ DTSTAMP:20170822T161502Z DTSTART:20180119T100000Z DTEND:20180119T110000Z CREATED:20170822T161502Z LAST-MODIFIED:20180111T171055Z LOCATION:Amphi DESCRIPTION:Twenty years ago the first exoplanet transit was detected. Whilst rare events\, transits are important as they give (accurate) information that cannot be obtained by any other means. In this talk i will review the status of transit surveys by looking at the original ground based surveys and how they have evolved to become state of the art with data approaching that of the quality of space based surveys. In addition I will examine the fundamental discoveries that have come from Space surveys and look forward to exciting results expected over the next decade. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Bernard Marty (CRPG Nancy) — CANCELLED UID:evenement266 @ DTSTAMP:20170822T161426Z DTSTART:20180112T100000Z DTEND:20180112T110000Z CREATED:20170822T161426Z LAST-MODIFIED:20180111T171022Z LOCATION:Amphi DESCRIPTION:Comets are among the most pristine solar system materials. Their abundant volatile species\, mainly in the form of ices\, are intimately mixed with refractory silicate-rich phases and organics\, the origins of which - either in the protosolar disk or the molecular cloud/interstellar medium - are actively debated. The origin of cometary matter and the potential contribution of comets to inner planet atmospheres are long-standing problems that were central in the definition of the ESA Rosetta mission exploring Comet 67P/Churyumov-Gerasimenko (67P/C-G). Noble gases are key tracers for the origin(s) and processing of volatile elements in the nascent solar system and in planetary atmospheres. The analysis of argon in Comet 67P/C-G has shown that comets are rich in noble gases\, suggesting that a significant fraction of these elements in the terrestrial atmosphere could be cometary. The Double Focusing Mass Spectrometer ROSINA DFMS has detected during a dedicated period in May 2016 not only argon\, but also krypton and xenon. In this talk we will present the results with special emphasis on Xe\, and discuss the implications for solar system formation scenarios\, as well as for the origin of volatile species on inner planets. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — Christmas break UID:evenement265 @ DTSTAMP:20170822T161357Z DTSTART:20180105T100000Z DTEND:20180105T110000Z CREATED:20170822T161357Z LAST-MODIFIED:20170822T161357Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — Christmas break UID:evenement264 @ DTSTAMP:20170822T161321Z DTSTART:20171229T100000Z DTEND:20171229T110000Z CREATED:20170822T161321Z LAST-MODIFIED:20170822T161321Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — Christmas break UID:evenement263 @ DTSTAMP:20170822T161251Z DTSTART:20171222T100000Z DTEND:20171222T110000Z CREATED:20170822T161251Z LAST-MODIFIED:20170822T161251Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Firas Mazyed (LAM) — PhD defence UID:evenement278 @ DTSTAMP:20171212T162722Z DTSTART:20171219T130000Z DTEND:20171219T140000Z CREATED:20171212T162722Z LAST-MODIFIED:20171212T162722Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Daisuke Kawata (UCL) — Thick and thin disk formation and evolution in the Milky Way UID:evenement262 @ DTSTAMP:20170822T161055Z DTSTART:20171215T100000Z DTEND:20171215T110000Z CREATED:20170822T161055Z LAST-MODIFIED:20171121T132622Z LOCATION:Amphi DESCRIPTION:Spectroscopic studies of the abundances of the Galactic disk stars clearly revealed two metal abundance sequences\, at high-[alpha/Fe] and low-[alpha/Fe]\, and high-[alpha/Fe] stars are generally older than low-[alpha/Fe] stars. These old high-[alpha/Fe] and young low-[alpha/Fe] populations are often considered as the thick and thin disk components\, respectively. Based on the results of the Auriga cosmological simulations\, we demonstrate that two pathways of the disk formation scenarios can naturally explain the observed distribution of these chemically distinct thick and thin disk stars in the Milky Way. We then discuss that the thin disk formation drives the radial migration of stars due to the development of the bar and the spiral arms\, and the vertical metallicity gradients for the mono-age populations\, which we observed in the Gaia DR1+RAVE data\, provide strong constraints on the radial migration and the structure of the Galactic thin disk. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — CANCELLED UID:evenement261 @ DTSTAMP:20170822T161032Z DTSTART:20171208T100000Z DTEND:20171208T110000Z CREATED:20170822T161032Z LAST-MODIFIED:20171206T132435Z LOCATION:Amphi DESCRIPTION:TBD CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Wilfried Jahn (LAM) — PhD defence UID:evenement276 @ DTSTAMP:20171128T171410Z DTSTART:20171205T130000Z DTEND:20171205T140000Z CREATED:20171128T171410Z LAST-MODIFIED:20171128T171410Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Joop Schaye (Leiden) — Simulating the formation of galaxies UID:evenement260 @ DTSTAMP:20170822T161002Z DTSTART:20171201T100000Z DTEND:20171201T110000Z CREATED:20170822T161002Z LAST-MODIFIED:20171128T182735Z LOCATION:Amphi DESCRIPTION:The realism of hydrodynamical simulations of the formation and evolution of populations of galaxies has improved considerably in recent years. I will try to give some insight into the reasons behind this success\, focusing in particular on the importance of subgrid models and the associated limitations. I will also present recent results from the cosmological EAGLE simulations as well as from other projects. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Sara Pipien (LAM) — PhD defence UID:evenement275 @ DTSTAMP:20171122T160147Z DTSTART:20171130T140000Z DTEND:20171130T160000Z CREATED:20171122T160147Z LAST-MODIFIED:20171122T160320Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:PhD Day UID:evenement277 @ DTSTAMP:20171128T171508Z DTSTART:20171130T080000Z DTEND:20171130T120000Z CREATED:20171128T171508Z LAST-MODIFIED:20171128T171508Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Romain Alata (LAM) — PhD defence UID:evenement274 @ DTSTAMP:20171122T160040Z DTSTART:20171127T133000Z DTEND:20171127T153000Z CREATED:20171122T160040Z LAST-MODIFIED:20171122T160308Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Olivier Absil (Liege) — Five years of harvest with the vortex coronagraph UID:evenement259 @ DTSTAMP:20170822T160820Z DTSTART:20171124T100000Z DTEND:20171124T110000Z CREATED:20170822T160820Z LAST-MODIFIED:20171024T155228Z LOCATION:Amphi DESCRIPTION:While the concept of vortex coronagraphy dates back to 2005\, the first science-grade Annular Groove Phase Masks (AGPM)\, working in the thermal infrared regime\, have been installed at the VLT only in 2012. They are now also equipping the Keck telescope and the Large Binocular Telescope\, and will soon be at the core of more ground-based high-contrast imaging instruments. In this seminar\, I will shortly review the technology development undertaken over the last 12 years\, and describe the on-sky operations and performance of the vortex coronagraph. I will then present the main scientific results obtained since 2012\, and explain how we have recently adapted deep learning techniques to the problem of post-processing in high-contrast imaging. I will finally discuss the perspectives with new instruments\, including the Breakthrough Watch project. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Mathieu Puech (GEPI) — Rotating discs vs. mergers at z 1 : is there really a disc survival issue in LCDM ? UID:evenement258 @ DTSTAMP:20170822T160754Z DTSTART:20171117T100000Z DTEND:20171117T110000Z CREATED:20170822T160754Z LAST-MODIFIED:20171026T132828Z LOCATION:Amphi DESCRIPTION:Discs represent 70% of local massive spirals. Such a large fraction has been suggested to be in tension with the relatively high occurrence rate of major mergers at higher redshifts in LCDM\, which has been dubbed as the "disc survival issue". Observations of the spatially-resolved kinematics and the high resolution morphology of their progenitors at z=0.6-1.2 suggest that gas-rich mergers is a viable solution to this issue. I will review observational evidences for this with a particular focus on the counter-arguments that have been discussed in the community\, e.g.\, the existence of a main sequence of star forming galaxies\, the large fraction of (U)LIRGs with spiral morphologies\, the low fraction of the SFR attributed to major mergers\, or the large fraction of spiral galaxies with no classical bulges (ie\, pseudo-bulges and bulgeless). I will show that none of these arguments are actually valuable counter-proofs of the prominent role of gas-rich major mergers in shaping a large fraction of local spiral galaxies. Finally\, I will discuss the current and future reliability of rotation curve measurements in distant galaxies\, focusing in particular on MOSAIC\, the future ELT multi-object spectrograph. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Jens Chluba (Manchester) — Cosmology Beyond Thermal Equilibrium : Future Steps with CMB spectral distortions UID:evenement257 @ DTSTAMP:20170822T160725Z DTSTART:20171110T100000Z DTEND:20171110T110000Z CREATED:20170822T160725Z LAST-MODIFIED:20171024T155127Z LOCATION:Amphi DESCRIPTION:Since the measurements with COBE/FIRAS in the mid-90’s we know that the energy spectrum of the cosmic microwave background (CMB) is extremely close to that of a perfect blackbody. However\, a number of early Universe processes should create spectral distortions at a level within reach of present day technology. I will give a broad-brush overview of recent theoretical and experimental developments\, explaining why future measurements of the CMB spectrum will open an unexplored new window to early-universe and particle physics. This provides an exciting new path forward in CMB cosmology which is complementary to planned and ongoing searches for primordial B-mode polarization signals. I will also highlight some of the challenges due to foregrounds. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — Fall break UID:evenement256 @ DTSTAMP:20170822T160651Z DTSTART:20171103T100000Z DTEND:20171103T110000Z CREATED:20170822T160651Z LAST-MODIFIED:20170822T160651Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Anaïs Bernard (LAM) — PhD defence UID:evenement269 @ DTSTAMP:20171024T155447Z DTSTART:20171027T120000Z DTEND:20171027T130000Z CREATED:20171024T155447Z LAST-MODIFIED:20171025T150007Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — Fall break UID:evenement255 @ DTSTAMP:20170822T160622Z DTSTART:20171027T090000Z DTEND:20171027T100000Z CREATED:20170822T160622Z LAST-MODIFIED:20170822T160622Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar — CANCELLED UID:evenement254 @ DTSTAMP:20170822T160543Z DTSTART:20171020T090000Z DTEND:20171020T100000Z CREATED:20170822T160543Z LAST-MODIFIED:20171024T155034Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Carlos Frenk (Durham) — A conclusive test of Cold Dark Matter UID:evenement253 @ DTSTAMP:20170822T160514Z DTSTART:20171013T090000Z DTEND:20171013T100000Z CREATED:20170822T160514Z LAST-MODIFIED:20171024T155005Z LOCATION:Amphi DESCRIPTION:The "Lambda cold dark matter’’ (LCDM) cosmological model is one of the great achievements in Physics of the past thirty years. Theoretical predictions formulated in the 1980s turned out to agree remarkably well with measurements\, performed decades later\, of the galaxy distribution and the temperature structure of the microwave background radiation. Yet\, these successes do not inform us directly about the nature of the dark matter. Indeed\, there are competing (and controversial) claims that the dark matter might have already been discovered\, either through the annihilation of cold\, or the decay of warm\, dark matter particles. In astrophysics the identity of the dark matter manifests itself clearly in the properties of dwarf galaxies\, such as the satellites of the Milky Way. I will discuss predictions from cosmological simulations assuming cold and warm (in the form of sterile neutrinos) dark matter and show how astronomical observations can conclusively distinguish between the two. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Paolo Padoan (Barcelona) — Supersonic Turbulence and Star Formation UID:evenement252 @ DTSTAMP:20170822T160417Z DTSTART:20171006T090000Z DTEND:20171006T100000Z CREATED:20170822T160417Z LAST-MODIFIED:20171024T154859Z LOCATION:Amphi DESCRIPTION:Supersonic turbulence and star formation are intimately linked. On the one hand\, the ubiquity of supersonic turbulence in the cold interstellar medium can be explained as the consequence of star formation\, because massive stars explode as supernovae\, releasing enough energy to sustain the turbulence. On the other hand\, star formation can be viewed as the consequence of supersonic turbulence\, because protostellar cores originate from random density enhancements caused by shocks in the turbulent flow. This direct link between turbulence and star formation is the fundamental reason why the star formation process may self-regulate at large scales ; it is also the fundamental reason for the apparent universality of the star formation rate and of the stellar mass distribution. Having unveiled the statistical properties of supersonic turbulence\, primarily through numerical studies\, we are now able to derive a statical theory of star formation where both the star formation rate and the initial mass function of stars can be predicted as a function of the fundamental non-dimensional parameters of star-forming regions\, such the ratios between kinetic\, gravitational\, magnetic and thermal energies. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Sara Jamal (LAM) — PhD defence UID:evenement273 @ DTSTAMP:20171025T150142Z DTSTART:20171002T120000Z DTEND:20171002T130000Z CREATED:20171025T150142Z LAST-MODIFIED:20171025T150151Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar UID:evenement251 @ DTSTAMP:20170822T160238Z DTSTART:20170929T090000Z DTEND:20170929T100000Z CREATED:20170822T160238Z LAST-MODIFIED:20170822T160238Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Anna Niemiec (LAM) — PhD defence UID:evenement272 @ DTSTAMP:20171025T150100Z DTSTART:20170926T120000Z DTEND:20170926T130000Z CREATED:20171025T150100Z LAST-MODIFIED:20171025T150100Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Ana Acebron (LAM) — PhD defence UID:evenement271 @ DTSTAMP:20171025T145932Z DTSTART:20170925T120000Z DTEND:20170925T130000Z CREATED:20171025T145932Z LAST-MODIFIED:20171025T145932Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:No seminar UID:evenement250 @ DTSTAMP:20170822T160057Z DTSTART:20170922T090000Z DTEND:20170922T100000Z CREATED:20170822T160057Z LAST-MODIFIED:20170822T160057Z CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Miguel Figueira (LAM) — PhD defence UID:evenement270 @ DTSTAMP:20171025T145852Z DTSTART:20170920T120000Z DTEND:20170920T130000Z CREATED:20171025T145852Z LAST-MODIFIED:20171025T145952Z LOCATION:Amphi CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Eric Prieto (LAM) — Tests d'intégration de NISP au LAM UID:evenement249 @ DTSTAMP:20170822T160018Z DTSTART:20170915T090000Z DTEND:20170915T100000Z CREATED:20170822T160018Z LAST-MODIFIED:20171024T154752Z LOCATION:Amphi DESCRIPTION:1. Présentation générale du NISP (Performance) 2. Présentation de la structure (par T. Pamplona) 3. Présentation du plan focal (par A. Bonnefoi) 4. Présentation du grism (par A. Costille) 5. Présentation des AIV/T CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Olivier Fauvarque (LAM) — PhD defence UID:evenement248 @ DTSTAMP:20170822T155916Z DTSTART:20170911T120000Z DTEND:20170911T130000Z CREATED:20170822T155916Z LAST-MODIFIED:20171025T145652Z LOCATION:Amphi DESCRIPTION:Optimization of Fourier based wave front sensors CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Roland Bacon (Lyon) — The MUSE Hubble Deep Field Survey UID:evenement247 @ DTSTAMP:20170822T155700Z DTSTART:20170908T090000Z DTEND:20170908T100000Z CREATED:20170822T155700Z LAST-MODIFIED:20170822T155700Z LOCATION:Amphi DESCRIPTION:The MUSE Hubble Deep Field Survey is deepest spectroscopic survey ever performed over the entire Ultra Deep Field (UDF) area. It provides 1700 spectroscopic redshifts\, an order of magnitude more compared to the data that has been accumulated on the UDF over the past decade\, up to AB 30 in magnitude and 6.7 in redshift. The depth and high quality of the data enables new and detailed studies of the physical properties of the galaxy population and their environments over a large redshift range. In this talk I will show in advance of publication a number of important results achieved by the survey on a diversity of topics : investigation of bias in photometric redshift\, spatially resolved stellar kinematics at z 1\, properties of CIII emitters\, FeII emission in stellar forming galaxies\, Lya luminosity function and its impact for reiniozation\, Lya extreme EW objects undetected in UDF\, Lya extended halos\, evolution of the galaxy major merger rate with redshift\, etc. CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT SUMMARY:Julien Girard (ESO) — VLT(I) Adaptive Optics Review : AO science machines from NACO to SPHERE and beyond UID:evenement246 @ DTSTAMP:20170426T134918Z DTSTART:20170707T090000Z DTEND:20170707T100000Z CREATED:20170426T134918Z LAST-MODIFIED:20170704T165651Z LOCATION:Amphi DESCRIPTION:Abstract : During this talk I will review past\, current and future adaptive optics fed instruments at the Very Large Telescope\, the challenge they represent from a science operations perspective. How do we maintain\, calibrate and sometimes improve them ? What diagnostics tools and metrics are key ? How can we best prepare the 3rd generation VLT instruments and the ELT ? I will focus on NACO and SPHERE\, the two instruments I supported as Instrument Scientist between 2009 and 2017. I will show some of their scientific highlights as well as original operations modes which can be game changers and open new parameter spaces\, new science niches and opportunities ! CATEGORIES:Présentation des séminaires URL: STATUS:CONFIRMED END:VEVENT END:VCALENDAR