Modified gravity from astrophysical observations

Series: 
Astronomy Unit Seminars
Speaker: 
Dr. Carlos Hidalgo (University of Portsmouth)
Date: 
September 28th, 2012 at 14:30
Room: 
GO Jones Room 410
Abstract: 

Dark matter in astrophysics is indirectly detected through its gravitational effects in luminous matter. However, its elusive nature has so far prevented a direct observation. This opens the alternative interpretation of astrophysical phenomena as the manifestation of modified gravity (MG).

In this talk I will review the set of astrophysical and cosmological observations, usually attributed to the dark sector, from the perspective of modified gravity. I will highlight the achievements of MG theories and the drawbacks for a complete theory. The main motivation of this work are recent analyses of the dynamics of wide binary star systems and clusters of stars. Both seem to favour a modified gravitational dynamics and challenge the dark matter picture instead. A phenomenological MG theory fitting these observations is finally put forward.