LAM - Laboratoire d’Astrophysique de Marseille

Abstract : TBD

Abstract : I will describe the first detection of a Super Massive Black Hole revealed by its Einstein Ring, in Hubble Frontier Field data, and also in the same data I will show three individual stars detected at high redshift that are magnified 100,000 times as they cross the lensing caustic of a moving cluster (predicted by Jordi Miralda Escude, 1991). These events we see are modulated by microlensing, consistent with the level predicted by the intra cluster light, and thoroughly exclude cluster dark matter comprised of 30M_sun black holes suggested by Bird etal on the basis of the first LIGO event. An alternative lower mass, higher redshift lensed solution for the first LIGO detection is also presented, incidentally.

Abstract : I will first summarize what we learned from HI observations using KAT-7, the precursor array of MeerKAT, the South African pathfinder for the SKA. I will then examine what we expect to be able to achieve, in the near future, with MeerKAT, MeerKAT+ FAST, SKA1 and SKA2.

NO Seminar — National Holiday

Abstract : Au cours de cet exposé, je montrerai comment l’étude des inclusions réfractaires et notamment des chondres, constituants principaux des météorites primitives, nous renseigne sur les conditions ayant régné au sein du disque protoplanétaire lors des 10 premiers millions d’années de notre système solaire.

Abstract : TBD

Abstract : Understanding the process responsible for transforming star forming galaxies into passive and quiescent systems is currently one of the hottest topics in astronomy. I will discuss recent observational results probing different mechanisms at work in different galaxies and at different epochs. I will present multi-wavelength observations providing evidence that powerful starburst-driven and AGN-driven outflows have a profound impact on the evolution of galaxies, both locally and at high redshift, by removing huge amount of gas. However such massive outflows may not be able to completely quench star formation in galaxies and actually, in some cases, such outflows can even boost star formation. I will show that the analysis of the stellar metallicities in large samples of local galaxies reveals that “starvation” ( i.e. the lack of gas inflows) is actually responsible for quenching star formation in most galaxies (at least in intermediate/low-mass galaxies). I will discuss the possible mechanisms responsible for galaxy starvation. I will also present some recent results from the ongoing Manga-SDSSIV survey, which is delivering integral field spectroscopy for thousands of galaxies and providing precious spatially resolved information of the quenching processes on different galactic scale.