Archives Séminaires 2019-2020

Séminaire

Séminaire IRAM/IPAG de Jonathan Freundlich (Université Hébraïque de Jerusalem), jeudi 5 septembre 2019 à 11h00, IRAM seminar room

Galaxy history is marked by a peak of star formation ten billion years ago and a subsequent drop of the star formation rate (SFR) by an order of magnitude. To understand this evolution, it is crucial to probe the gas reservoirs from which stars are formed.
With programs observing the molecular gas phase in typical star-forming galaxies at different epochs, I will present how the cosmic evolution of the SFR is mainly driven by that of the molecular gas fraction.
The depletion time (…)

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Séminaire IPAG de Sibylle Anderl (Frankfurter Allgemeine Zeitung), jeudi 12 septembre 2019 à 11h00, IPAG seminar room

Today, we live in times when science seems increasingly under attack in public : Scientific expertise and the validity of scientific knowledge is being questioned by many holding populist views. At the same time, science is key for many of the central future-challenges we face as human beings. In this situation, scientific popularization seems particularly important and very much needed. But the intention to communicate scientific topics gives rise to many questions : Who should do the job (…)

Séminaire exceptionnel

Séminaire IPAG de Bo Reipurth (University of Hawaii), vendredi 13 septembre 2019 à 14h, IPAG Seminar room

George Herbig, one of the giants of 20th century astronomy, almost singlehandedly founded the study of young stars, a subject on which he worked for more than 60 years.
In this presentation I will briefly talk about Herbig’s life, but the emphasis will be on the scientific results that Herbig achieved, first at Lick Observatory and later at the University of Hawaii.
In addition to his work on star formation, Herbig became the leader in the study of diffuse interstellar bands, and he had (…)

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Séminaire IPAG de William Chantereau (Liverpool John Moore University), jeudi 19 septembre 2019 à 11h00, IPAG seminar room

Globular clusters are among the oldest and brightest structures in the Universe, and are therefore witnesses of processes from the early up to the present-day Universe. In turn, they play a major role in the benchmark for stellar evolution theory and they are used to constrain the assembly histories of galaxies.
Over the last decades, several pieces of ground-breaking observational evidence were accumulated pointing out the presence of multiple stellar populations with different chemical (…)

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Séminaire IPAG de Nicolas Cuello (Université Catholique du Chili), jeudi 26 septembre 2019 à 11h00, IPAG seminar room

Three facts : stellar multiplicity is high during early stellar evolution, planet formation occurs early on, and planets are detected in multiple stellar systems.
Three consequences : planet formation does not occur in isolation, planet formation is resilient, and the environment of stellar formation affects the final planetary architecture.
In this talk we explore circumbinary discs dynamics and also discs affected by stellar flybys, mainly through 3D SPH hydrodynamical simulations. (…)

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Séminaire IPAG de Bernard Schmitt (IPAG), jeudi 3 octobre 2019 à 11h00, IPAG seminar room

Après le survol de Pluton et ses 5 lunes le 14 Juillet 2015, la sonde New Horizons a été très légèrement déviée pour poursuivre son périple vers les confins du Système Solaire avec pour but la première exploration d’un objet de la Ceinture de Kuiper, au-delà de l’orbite de Neptune.
Le survol de cet objet, surnommé Ultima Thulé, a eu lieu le premier Janvier 2019 à une altitude de 3500km et a dévoilé un objet bilobé de forme et géologie assez inattendue. Les observations effectuées apportent (…)

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Séminaire IPAG de Junko Isa (IPAG), jeudi 10 octobre 2019 à 11h00, IPAG seminar room

The origin of the solar system and subsequent processes governing the production and evolution of organic matter are still not well understood. The fact that the vast majority of organic compounds are subject to reactions that lead to synthesis, degradation, and alteration confuses the overall distribution and diversity of organics. Among the complex organic compounds in the universe, soluble organic compounds, SOCs, such as the ones that are essential for life have been identified in (…)

Séminaire exceptionnel

Séminaire IPAG de Thierry Montmerle (IAP), vendredi 11 octobre 2019 à 9h30, IPAG seminar room

It is well known that supernova remnants (SNR) can accelerate particles. While indirect evidence for acceleration of protons is found in the gamma-ray domain when SNR shocks interact with nearby molecular clouds (pi-0 devay), direct evidence for electron acceleration is found from radio and X-ray observations (synchrotron emission). But SNR are not the only source of shock waves in the Galaxy : the so-called "runaway stars", resulting mainly from ejection from a close binary system or a (…)

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Séminaire IPAG de Monika Moscibrodzka (Radboud University), jeudi 17 octobre 2019 à 11h00, IPAG seminar room

One and three millimeter Very Long Baseline Interferometry experiments are constructing the images of the plasma flows in the immediate vicinity of the supermassive black holes at the centers of Milky Way and M87 galaxies. A detailed theoretical understanding of black hole astrophysics is now very crucial to interpret these observations.
The focus of the talk is on modeling total intensity and polarimetric properties of light produced in synchrotron processes and inverse-Compton process in (…)

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Séminaire IPAG de Niranjan Thatte (University of Oxford), jeudi 7 novembre 2019 à 11h00, IPAG seminar room

ESO’s Extremely Large Telescope (ELT) is set to become the world’s largest optical-infrared telescope in a few years’ time. With its enormous collecting area (nearly 1000 m^2), and with an adaptive mirror built-in to routinely achieve diffraction limited resolution (0.01 arcseconds), the ELT is set to transform observational astrophysics in the next decade.
HARMONI will be the “work-horse” first-light integral field spectrograph, fully equipped with multiple flavours of adaptive optics, (…)