Lectures (PowerPoint presentations)

Gaseous phases in galaxies	Scuola Nazionale di Astrofisica,  Cetraro, 3 - 9 Giugnio, 2002
Future large radio telescopes	Scuola Nazionale di Astrofisica,  Cetraro, 3 - 9 Giugnio, 2002
Dwarf Galaxies: Building Blocks of the Universe	International Max-Planck Research School Bonn, 8 April, 2002
Merging galaxy clusters: radio and X-ray studies	International Max-Planck Research School Bonn, 8 April, 2002
Gefährdung der Erde durch Supernovae?	Öffentlicher Vortrag, Bad Neuenahr, 25. November 2002
Wundersames Weltall: Dunkle Materie und Dunkle Energie	Vortrag beim Lions-Club in Moers, 11. Juli 2005
LOFAR	Seminar given at RAIUB, November 9, 2005
High-Precision Rotation Curves of Disk Galaxies	Colloquium held at Univ. of Heidelberg, December 21, 2004, and at Univ. of Vienna, October 5, 2005
Rotation Curves of Disk Galaxies: New Perspectives	Colloquium held at Univ. Athens, April 6, 2006
Radio halos and relics in galaxy clusters	Seminar given at AIfA, May 22, 2006
LOFAR - ein Quantensprung in der Radioastronomie	Öffentlicher Vortrag am Planetarium Hamburg, June 8, 2007
Dark Matter in Gas-rich Galaxies	Lectures held at Novicosmo, September 2006, 2007
Leuchtende und Dunkle Materie in Galaxien	Public lecture held at AIfA-Konferenz, Bad Honnef, October 26, 2007
Dunkle Materie und Dunkle Energie	Ringvorlesung, Univ. Bochum, 21.4.2009