Strong Gravitational Lensing as a Probe of Gravity, Dark-Matter and Super-Massive Black Holes

Understand

Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still ill-defined.

• Strong gravitational lensing furnishes a powerful method to probe gravity in the central regions of galaxies.
• It can (1) provide a unique detection-channel of dark-matter substructure beyond the local galaxy group, (2) constrain dark-matter physics, complementary to direct-detection experiments, as well as metric theories of gravity, (3) probe central super-massive black holes, and (4) provide crucial insight into galaxy formation processes from the dark matter point of view, independently of the nature and state of dark matter.
• To seriously address the above questions, a considerable increase in the number of strong gravitational-lens systems is required.