Seminar 1:  Bulk flow measurement and Hubble tension

Parinaz Sheikhansari

Department of Physics, Sharif University of Technology

Seminar 2: Mergers of primordial black holes in extreme clusters and the H0 tension

Yasaman Khalaj Masoumi

Department of Physics, Sharif University of Technology

 

Abstract 1: The standard cosmological model has been successful in describing many observations from widely different epochs of the Universe, from primordial nucleosynthesis to the accelerating expansion of the present day. With the improvement of the number and the accuracy of observations, some inconsistencies among key cosmological parameters of the model have emerged. One of these discrepancies is between the early and late time measurements of H0.

Some alternative models are proposed to alleviate H0. The question is how these models predict other cosmological observations. In this work, we measured bulk flow in the LCDM model and the uLCDM model to see how bulk flow changes in uLCDM and investigate whether it can reconcile H0 tension.

Abstract 2: The simplest ΛCDM model provides a good fit to a large span of cosmological data. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the model have emerged. The most statistically significant tension is the 4σ to 6σ disagreement between predictions of the Hubble constant. There are many proposals beyond the ΛCDM model to reconcile the tension, like early dark energy (EDE model), primordial magnetic field, mergers of primordial black holes in extreme clusters. The model which we have been focused on is the mergers of primordial black holes in extreme clusters. In this talk, I will discuss several models which proposed PBHs are clustered, therefore, the gravitational waves emitted by collisions of such PBH binaries could resolve the Hubble tension

 

 

یکشنبه 31 مرداد 1400، ساعت 19:00

Sunday 22 August 2021 – 19:00 Tehran Time

اتاق سمینار مجازی –Virtual Seminar Room

https://vc.sharif.edu/ch/cosmology

گزینه ورود به صورت مهمان – Enter as a Guest