Archives Séminaires 2014-2015

Séminaire

Séminaire IPAG de Kevin Heng (University of Bern), jeudi 18 décembre 2014 à 11h00, IPAG seminar room

Understanding the atmospheres of exoplanets is the next frontier of exoplanet science. I will review the physics and chemistry associated with exoplanetary atmospheres. My focus is on the assumptions and techniques associated with theory and simulation and how they may influence (or even mislead) our interpretation of the data. First, I will discuss atmospheric radiative transfer and inversion (retrieval) techniques, reviewing the progress made in the field so far and critiquing the (...)

Séminaire

Séminaire IPAG de Natalie Webb (IRAP), jeudi 8 janvier 2015 à 11h00, IPAG seminar room

Ultra Luminous X-ray (ULX) sources are defined as off-nuclear point-like X-ray sources with X-ray luminosities that exceed the Eddington limit for a 10 solar mass black hole. Their nature is still unclear, but it has been proposed that these objects may be stellar mass black holes accreting above the Eddington limit, although a mechanism is yet to be identified for exceeding this theoretical limit. Alternatively, they may be the much sought after intermediate mass black holes, that are (...)

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Séminaire IPAG de Cyril Szopa (LATMOS), jeudi 8 janvier 2015 à 11h00, IPAG seminar room

Detection, identification and quantification of volatile materials present in alien worlds are key measurements to characterize the nature, the origin, and the evolution of these environments, as well as their potential connection to the origin of life in the solar system. These volatiles can exist in various states (gases in atmospheres, condensates in cold worlds, components of inorganic (e.g. rocks) or organic (e.g. organic aerosols) matrixes…) and they can be distributed in a variety (...)

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Séminaire IPAG de Alexandre Santerne (Universidade do Porto), jeudi 22 janvier 2015 à 11h00, IPAG seminar room

The Kepler space telescope has observed hundred of thousands of stars continuously during the four years of the prime mission. It has detected thousands of potential transiting planets up to 1AU and down to the size of the Earth. These detections provide new constraints to the theories of planet formation, migration, and evolution, at a level never reached before. However, transit signals could be mimicked by other, non-planetary scenarios. These other scenarios, the so-called false (...)

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Séminaire IPAG de Patrick Hennebelle (CEA/Saclay), jeudi 29 janvier 2015 à 11h00, IPAG seminar room

While the existence of massive filaments is known since several decades, the Herschel Space Observatory has revealed that filaments are ubiquitous in the ISM and has permitted to quantify their properties. Interestingly, many of them do not appear to be self-gravitating implying that self-gravity cannot be the only mechanism at the origin of their existence. Deciphering the various regimes and processes at play in this context, is important. First of all, filaments could possibly have an (...)

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Séminaire IPAG de Barbara Comis (LPSC), jeudi 5 février 2015 à 11h00, IPAG seminar room

As the last step of the hierarchical structure formation process, clusters of galaxies represent the largest gravitationally bound objects that we can observe in our Universe. Since they formed all along the cosmic history, they contain plenty of information about the evolution of our Universe, and can then provide a strong tool for cosmological investigation, complementary to CMB.
Clusters are dominated by dark matter (85% of their total masses), while most of their baryons are present as (...)

Séminaire exceptionnel

Séminaire IPAG de Jacques Lepine (Université de Sao Paulo), vendredi 6 février 2015 à 11h00, IPAG seminar room

LLAMA is a collaboration between Argentina and Brazil to install a 12m radiotelescope in the Andes, at 4800m altitude, and at 150 km in straight line from ALMA. Thanks to the high altitude and the dry atmosphere of the site, the atmospheric transmission, permits molecular line observations up to ≈ 800 GHz. The telescope will be equipped with several heterodyne, broad-band receivers covering the spectral windows from millimetre to submillimeter wavelength, between 100 and 800 GHz, coupled (...)

Séminaire

Séminaire IPAG de Matthieu Tristram (LAL), jeudi 26 février 2015 à 11h00, IPAG seminar room

Planck is the ESA telescope launched in 2009 that surveyed with unprecedented precision the Cosmic Microwave Background (CMB), providing with the highest resolution measurements so far of the CMB temperature and polarization anisotropies. The first Planck release happened in 2013. The second Planck data release that includes the full mission and the first Planck polarization data has just become available. In this talk I will give an overview of the new Planck results, focusing on the (...)

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Séminaire IPAG de Jose Cernicharo (CSIC/INTA, Spain), jeudi 5 mars 2015 à 11h00, IPAG seminar room

Evolved stars are the factories of cosmic dust. This dust is made of tiny grains that are injected into the interstellar medium and plays a key role in the evolution of astronomical objects from galaxies to the embryos of planets. However, the fundamental processes involved in dust formation and evolution are still a mystery.
The aim of the NANOCOSMOS project is to take advantage of the new generation telescopes and simulation experiments to progress in our understanding of the dust (...)

Séminaire

Séminaire IPAG de Dimitrios Gouliermis (MPIA), jeudi 12 mars 2015 à 11h00, IPAG seminar room

Stars are born in groups of various shapes, sizes and degree of "boundness". Different types of stellar systems, from compact dense clusters to extended stellar associations, are not however independent to each other, but manifestations of the same hierarchy in the star formation process. This is supported from observations of resolved star-forming regions, where compact stellar clusters seem to represent the centers of recent star formation within larger loose stellar structures of older (...)