Date:
15. June 2018 - 11:30
Speaker:
Akshay Rana (University of Delhi)
In General Relativity (GR), the graviton is massless. However, a common feature in several theoretical alter-
natives of GR is a non-zero mass for the graviton. These theories can be described as massive gravity theories.
Despite many theoretical complexities in these theories, on phenomenological grounds the implications of massive
gravity have been widely used to put bounds on graviton mass. One of the generic implications of giving a mass
to the graviton is that the gravitational potential will follow a Yukawa-like fall off. The use of this feature of
massive gravity theories to probe the mass of graviton by using the largest gravitationally bound objects, namely
galaxy clusters would be discussed. Further, an analysis would be shown where we use the mass estimates of
galaxy clusters measured at various cosmologically defined radial distances measured via weak lensing (WL) and
Sunyaev-Zeldovich (SZ) effect. We also uses the model independent values of Hubble parameter H(z) smoothed by
a non-parametric method, Gaussian process. This analysis improves the upper bound on graviton mass obtained
earlier from galaxy clusters.



