|Time：1121212 (Tue.) 12:00~14:00
Speaker：二間瀬 敏史(Toshifumi Futamase)
Professor Emeritus, Astr, Tohoku University
Title：A possible interpretation of Hubble tension by the observed inhomogeneous matter density
Abstract：Hubble parameter describes the expansion rate of the universe and is one of the most important parameter to characterize our universe. Thus the measurement has been a major topic in the observational cosmology. Recently there has been a significant discrepancy in the measured value depending on the method of the observation. This is called as the Hubble tension. If the discrepancy is real, it will cause a revolutionary change in the standard cosmology. I show that the inhomogeneous matter distribution observed by K-band luminosity density naturally explain the tension without introducing artificial change in dark energy. For this purpose Einstein equation is averaged over an arbitrary finite region to construct local Friedman universe, and the relation between local and horizon scale cosmological parameters. This relation can explain the observed discrepancy of Hubble parameter. For students who are not familiar with cosmology, I give a brief introduction of the necessary knowledge on cosmology and astronomy such as the Hubble parameter and distance-redshift relation.
Place：F104, Gongguan Campus, NTNU