Le 28 octobre 2014
De 14h00 à 15h00
Mariya LYUBENOVA
Kapteyn Astronomical Institute, Groningen
Observations made over the last few decades have shown that nucleation is a common phenomenon in the centres of all types of galaxies, with a minimum 65% hosting nuclear star clusters (NSCs) in their photometric and kinematic centres. Many of these NSCs are believed to co-exist with super massive black holes and it was suggested that the former might be the precursors of the latter. Although still very limited in number, detailed studies of galactic nuclei in nearby spiral galaxies have revealed a plethora of phenomena: NSCs appear to be flattened, embedded in stellar or gaseous disks, contain multiple stellar populations, and co-rotate with respect to the main body of the host galaxy. How were such complex structures formed and how did they evolve? Did NSCs form in situ via dissipational sinking of gas to the galactic centre and subsequent star formation? Or did they migrate towards the centre of the galaxy due to dynamical friction? I will review our ongoing studies of NSCs in particular of early-type galaxies using Adaptive Optics assisted integral field spectroscopy in a combination with HST imaging and long-slit spectroscopy. Our first findings suggest that NSCs are not a single class of objects with each observed cluster displaying a variety of properties in terms of kinematics and stellar populations.