演講資訊

摘要：

The dark matter, or more accurately “missing mass”, problem could well be the most important and most long standing issue in astrophysics. In this work, we review this problem from the galaxies scale to the cosmology. Then, we focus on the alternative solution “Modified Newtonian Dynamics” (MOND) which interprets “missing mass” as “acceleration discrepancy”. We also introduce relativistic gravity theories in MOND. Our work focuses especially on gravitational lensing and time delay within the relativistic version of MOND. We derive the lensing formulation in relativistic MOND and test it on strong lensing cases. Although the results are preliminary for the spherically symmetric case, the lens mass of an elliptical galaxy in lensing and the Hubble constant in time delay are still consistent within the relativistic MOND paradigm. Moreover, the masses of lens galaxies estimated from dynamics and from gravitational lensing are also consistent in our study.