Title: Can ΛCDM model reproduce MOND-like behavior?

Speaker: 戴德昌 特别研究员
Institute: 上海交通大学(SJTU)
Time: 2018.03.08（Thursday） 14:30
Place: Physics Building 573, Haiyun Campus, Xiamen University

Abstract: It is usually believed that MOND can describe the galactic rotational curves with only baryonic matter and without any dark matter very well, while the ΛCDM model is expected to have difficulty in reproducing MOND-like behavior. Here, we use EAGLE's data to learn whether the ΛCDM model can reproduce MOND-like behavior. EAGLE's simulation result clearly reproduces the MOND-like behavior for a_b   10^{−12}m/s^2 at z = 0, although the acceleration constant, a_0, is a little larger than the observational data indicate. We find that a_0 increases with the redshift in a way different from what Milgrom proposed (a_0 ∝ H). Therefore, while galaxy rotation curves can be fitted by MOND's empirical function in the ΛCDM model, there is no clear connection between a0 and the Hubble constant. We also find that a_0 at z>   1 is well separated from a_0 at z = 0. Once we have enough galaxies observed at high redshifts, we will be able to rule out the modified gravity model based on MOND-like empirical function with a z-independent a_0.