Abstract Details

Name: Kamal Bora
Affiliation: Indian Institute of Technology, Hyderabad
Conference ID: ASI2021_546
Title : Constraints on the variation of fine structure constant from joint SPT-SZ and XMM-Newton observations
Authors and Co-Authors : Kamal Bora(Indian Institute of Technology, Hyderabad), Dr. Shantanu Desai(Indian Institute of Technology, Hyderabad)
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : We search for a variation of the electromagnetic fine structure constant (α ≡ e^2/ℏc) using a sample of 58 SZ selected clusters in the redshift range (0.2 < z < 1.5) detected by the South Pole Telescope, along with X-ray measurements using the XMM-Newton observatory. We use the ratio of the integrated SZ Compto-ionization to its X-ray counterpart as our observable for this search. We first obtain a model-independent constraint on α of about 0.7%, using the fact that the aforementioned ratio is constant as a function of redshift. We then look for logarithmic dependence of α as a function of redshift: ∆α/α = −γ ln(1 + z), as this is predicted by runaway dilaton models. We find that γ = −0.046 ± 0.1, which indicates that there is no logarithmic variation of α as a function of redshift. We also search for a dipole variation of the fine structure constant using the same cluster sample. We do not find any evidence for such a spatial variation.