Cafe-Club, Michal BILEK (LERMA, Observatoire de Paris; Collège de France; Université de Strasbourg): « What is the origin of the different kinematic morphologies of early-type galaxies? ».

Michal BILEK (LERMA, Observatoire de Paris; Collège de France; Université de Strasbourg), who will talk about « What is the origin of the different kinematic morphologies of early-type galaxies? ».

You can find the schedule of upcoming café-clubs and the video of old ones at http://wiki.lam.fr/geco/CafeClub

Take care,
Carlo, Meriam, Mathilde

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ABSTRACT

Early-type galaxies (i.e. elliptical and lenticular) are divided into slow and fast rotators according to the appearance of their maps of
line-of-sight velocity. Fast rotators show clear ordered rotation, while slow are supported mostly by velocity dispersion. I will speak about our work on investigation of the origin of this diversity. Inspired by cosmological simulations, we assumed that galaxies first form as fast rotators and then mergers transform some of them to slow rotators. We investigated the correlations of a measure of rotational support with various properties of galaxies that are sensitive to mergers. These include stellar ages, the presence of tidal features, and kinematically distinct cores. Each of these parameters is sensitive to a different type of merger and has a different lifetime. The found correlations, or their lack, together with observations of high-redshift universe, are explained the easiest, if the rotation support of early-type galaxies was decreased by multiple minor wet mergers more than 10 Gyr ago. Moreover, galaxies with a low rotational support continue accreting more satellites until today.